Item 1. Business

General

We are a Delaware limited partnership formed by Westlake in March 2014 to operate, acquire and develop ethylene production facilities and related assets. On August 4, 2014, we completed our initial public offering (the "IPO") of 12,937,500 common units representing limited partner interests. In connection with the IPO, we acquired a 10.6% interest in OpCo and a 100% interest in OpCo GP, which is the general partner of OpCo. On April 29, 2015, we purchased an additional 2.7% newly-issued limited partner interest in OpCo, resulting in an aggregate 13.3% limited partner interest in OpCo effective April 1, 2015. Effective August 30, 2017, the subordination period for the 12,686,115 subordinated units owned by Westlake ended and the subordinated units converted into common units on a one-for-one basis and thereafter participate on terms equal with all other common units in distributions of available cash. On September 29, 2017, we completed a secondary offering of 5,175,000 common units at a price of $22.00 per unit and purchased an additional 5.0% newly-issued limited partner interest in OpCo, resulting in an aggregate 18.3% limited partner interest in OpCo, effective as of July 1, 2017.

Our business and operations are conducted through OpCo. Because we own OpCo's general partner, we have control over all of OpCo's assets and operations. As of December 31, 2017, Westlake held an 81.7% limited partner interest in OpCo and held a 43.8% limited partner interest in us (consisting of 14,122,230 common units), our general partner interest and our incentive distribution rights.

OpCo's assets are comprised of three ethylene production facilities, which primarily convert ethane into ethylene and have an aggregate annual capacity of approximately 3.7 billion pounds, and a 200-mile ethylene pipeline. OpCo derives substantially all of its revenue from these ethylene production facilities. Ethylene is the world's most widely used petrochemical in terms of volume and is a key building block used to produce a number of key derivatives, such as polyethylene ("PE") and polyvinyl chloride ("PVC"), which are used in a wide variety of end markets including packaging, construction and transportation. Westlake's downstream PE and PVC production facilities consume a substantial majority of the ethylene produced by OpCo. OpCo generates revenue primarily by selling ethylene to Westlake and others, as well as through the sale of co-products of ethylene production, including propylene, crude butadiene, pyrolysis gasoline and hydrogen. Our sole revenue generating asset is our 18.3% limited partner interest in OpCo.

Our assets and operations are organized into a single reportable segment and are all located and conducted in the United States. See "Item 8. Financial Statements and Supplementary Data" for financial information on our operations and assets; such information is incorporated herein by reference.

Among other agreements entered into in connection with the closing of the IPO, OpCo entered into a 12-year ethylene sales agreement with Westlake, under which Westlake agreed to purchase 95% of OpCo's planned ethylene production each year, on a cost-plus basis that is expected to generate a fixed margin per pound of $0.10 (the "Ethylene Sales Agreement"). Any ethylene not sold to Westlake and all co-products that are produced by OpCo will be sold to third parties on either a spot or contract basis. OpCo also entered into a feedstock supply agreement with Westlake that supplies OpCo with all of the ethane (and any other feedstocks) required for OpCo to produce ethylene under the Ethylene Sales Agreement (the "Feedstock Supply Agreement").

OpCo primarily uses ethane (a component of natural gas liquids, or NGLs) to produce ethylene. OpCo completed an upgrade and capacity expansion of its Petro 1 ethylene unit at our Lake Charles site in 2016. The Petro 1 expansion project increased OpCo's ethylene capacity by approximately 250 million pounds annually. OpCo completed an expansion project to increase the ethylene capacity at our Calvert City facility in the second quarter of 2017. The expansion, along with other initiatives, increased ethylene capacity by approximately 100 million pounds annually.

Ownership of Westlake Chemical Partners LP

The following simplified diagram depicts our organizational structure as of December 31, 2017 :

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Our Assets and Operations

Our sole revenue generating asset is our 18.3% limited partner interest in OpCo. We also own the general partner interest of OpCo. OpCo owns:

As the owner of the general partner interest of OpCo, we control all aspects of the management of OpCo, including its cash distribution policy. See "—OpCo's Assets."

OpCo's Assets

Ethylene Production Facilities . OpCo operates three ethylene production facilities that are situated on real property leased to OpCo by Westlake pursuant to two 50-year site lease agreements. See "Our Agreements with Westlake—Site Lease Agreements" for a description of the site leases. Ethylene can be produced from either NGL feedstocks, such as ethane, propane and butane, or from petroleum-derived feedstocks, such as naphtha. Lake Charles Olefins and Calvert City Olefins use primarily ethane as their feedstock. Calvert City Olefins can also use propane as a feedstock and Petro 2 can also use an ethane/propane mix, propane, butane or naphtha as a feedstock.

The following table provides information regarding OpCo's ethylene production facilities as of December 31, 2017 :

Lake Charles Olefins

Two of OpCo's ethylene production facilities, which we refer to as Petro 1 and Petro 2 and, collectively, as Lake Charles Olefins, are located at Westlake's Lake Charles site. The combined capacity of these two ethylene production facilities is approximately 3.0 billion pounds per year.

Within Westlake's Lake Charles site, Petro 1 and Petro 2 are connected by pipeline systems to Westlake's polyethylene plants. Westlake may use the ethylene it purchases from OpCo at its Lake Charles facility or transfer it to its Geismar facility or its Longview facility, either through physical transportation or via exchange transactions. Westlake may also use the ethylene it purchases from OpCo with chlorine to produce ethylene dichloride and transport it via barge to Westlake's Calvert City site.

In addition, OpCo produces ethylene co-products including chemical grade propylene, crude butadiene, pyrolysis gasoline and hydrogen. OpCo sells its output of these co-products to external customers.

Calvert City Olefins

One of OpCo's ethylene production facilities is located at Westlake's Calvert City site, which we refer to as Calvert City Olefins. The capacity of Calvert City Olefins is approximately 730 million pounds per year.

Pipeline

OpCo owns a 200-mile 10-inch diameter ethylene pipeline system that connects the Equistar Pipeline, the Flint Hills Pipeline and the Lone Star Storage Facility in Mont Belvieu to the Longview, Texas chemical site, which includes Westlake's Longview PE production facility. The system has a capacity of 3.5 million pounds per day of ethylene and is operated as a common carrier pipeline by Buckeye Development & Logistics I LLC. As a common carrier intrastate pipeline in Texas, the

system is subject to rate regulation under the Texas Utilities Code, as implemented by the Texas Railroad Commission, or the TRRC, and has a tariff on file with the TRRC.

Technology

OpCo has perpetual and paid-up licenses for steam cracking and process recovery technology used at its ethylene plants.

Our Agreements with Westlake

Except as otherwise indicated, the agreements described below became effective on August 4, 2014, concurrent with the closing of the IPO.

Ethylene Sales Agreement

OpCo and Westlake entered into the Ethylene Sales Agreement, which has an initial term through December 31, 2026 and automatic 12-month renewal periods until terminated at the end of the initial term or any renewal term on 12-months' notice. The Ethylene Sales Agreement requires Westlake to purchase OpCo's planned ethylene production each year, subject to certain exceptions and a maximum commitment of 3.8 billion pounds per year, less product sold by OpCo to third parties equal to approximately 5% of the annual output. If OpCo's actual production is in excess of planned ethylene production, Westlake has the option to purchase up to 95% of production in excess of planned production. Westlake's purchase price for ethylene under the Ethylene Sales Agreement includes a $0.10 per pound margin, the total costs incurred by OpCo for the feedstock and natural gas to produce each pound of ethylene (subject to a usage cap and a floor), and estimated operating costs, maintenance capital expenditures and other turnaround expenditures, less net proceeds from co-products sales. This purchase price is not designed to cover capital expenditures for expansion. Variable costs not incurred by OpCo due to a deficiency in takes are rebated to Westlake. Under specified circumstances, unrecovered costs may be carried forward for recovery in subsequent years.

On August 4, 2016, OpCo and Westlake entered into an amendment to the Ethylene Sales Agreement in order to provide that certain of the pricing components that make up the price for ethylene sold thereunder would be modified to reflect the portion of OpCo's production capacity that is used to process Westlake's purge gas instead of producing ethylene and to clarify that costs specific to the processing of Westlake's purge gas would be recovered under the Services and Secondment Agreement, and not the Ethylene Sales Agreement.

Feedstock Supply Agreement

OpCo and Westlake entered into the Feedstock Supply Agreement, which has an initial term through December 31, 2026 and automatic 12-month renewal periods until terminated at the end of the initial term or any renewal term on 12-months' notice. Under the Feedstock Supply Agreement, Westlake agrees to sell OpCo ethane and other feedstock in amounts sufficient for OpCo to produce the ethylene to be sold under the Ethylene Sales Agreement. The price at which ethane and feedstock is sold includes an indexed price for spot gas liquids at Mont Belvieu and applicable transportation, storage and other costs.

Services and Secondment Agreement

OpCo and Westlake entered into the Services and Secondment Agreement, pursuant to which OpCo will provide Westlake with various utilities and utility services and in exchange for Westlake providing OpCo with various utility services, comprehensive operating services for OpCo's units, services for the maintenance and operation of the common facilities and seconded employees to perform all services required under the agreement.

Site Lease Agreements

OpCo and Westlake entered into two 50-year site lease agreements (the "Site Leases"). Under the Site Leases, OpCo leases the real property underlying Calvert City Olefins and Lake Charles Olefins and is granted certain use and access right related thereto, for a base rental amount of $1 per year per site. Each of the Site Leases is terminable by the lessor upon the occurrence of certain events of default or by OpCo if Calvert City Olefins or Lake Charles Olefins, as applicable, is destroyed by casualty. Pursuant to the Site Leases, the lessor has the right to restore and repurchase the units for fair market value if OpCo fails to expeditiously restore Calvert City Olefins or Lake Charles Olefins, as applicable, following a casualty loss. Subject to the foregoing repurchase right, OpCo may remove its ethylene production facilities and other related improvements for up to one year after expiration or termination of the applicable Site Lease, so long as such removal can be accomplished without material damage or harm to the lessor's property or operations; provided that any assets that are not timely removed by OpCo will be deemed to have been surrendered to the lessor.

Omnibus Agreement

We entered into the Omnibus Agreement with Westlake and OpCo, pursuant to which we granted Westlake, among other things, a right of first refusal on any proposed transfer of (1) our equity interests in OpCo, (2) the ethylene production facilities that serve Westlake's other facilities or (3) certain other assets we may acquire from Westlake. The Omnibus Agreement also provides for reimbursement to Westlake for the provision of various administrative services and direct expenses incurred on our behalf and in connection with the operation of our business. Under the Omnibus Agreement, Westlake will indemnify us against certain environmental and other losses, and we will indemnify Westlake against certain environmental and other losses for which Westlake is not otherwise obligated to indemnify us and certain other losses and liabilities to the extent resulting from the provision of services by Westlake to us.

Exchange Agreement

OpCo and Westlake entered into an exchange agreement, which had an initial term through August 1, 2015 and is continuing year to year thereafter, unless and until terminated by either party. Under the exchange agreement, OpCo may require Westlake to deliver up to 200 million pounds of ethylene for OpCo per year from the Site Leases to an ethylene hub in Mt. Belvieu, Texas, for which OpCo would be required to pay Westlake an exchange fee of $0.006 per pound.

OpCo Partnership Agreement

We, OpCo GP and Westlake entered into an agreement of limited partnership for OpCo (the "OpCo LP Agreement"). The OpCo LP Agreement governs the ownership and management of OpCo and designates OpCo GP as the general partner of OpCo. OpCo GP generally has complete authority to manage OpCo's business and affairs. We control OpCo GP, as its sole member, subject to certain approval rights held by Westlake.

Investment Management Agreement

On August 1, 2017, the Partnership, OpCo and Westlake executed an Investment Management Agreement that authorized Westlake to invest the Partnership and OpCo’s excess cash with Westlake for a term of up to a maximum of nine months. Per the terms of the Investment Management Agreement, the Partnership earns a market return plus five basis points and Westlake provides daily availability of the invested cash to meet any liquidity needs of the Partnership or OpCo.

See "Liquidity and Capital Resources" in Item 7. "Management's Discussion and Analysis" for discussions of the Partnership's and OpCo's debt agreements with Westlake and "Interest Rate Risk" in Item 7A. "Quantitative and Qualitative Disclosures about Market Risk" for the Partnership's interest rate contract with Westlake.

Environmental

As is common in our industry, we and OpCo are subject to environmental laws and regulations related to the use, storage, handling, generation, transportation, emission, discharge, disposal and remediation of, and exposure to, hazardous and non-hazardous substances and wastes in all of the countries in which we do business. National, state or provincial and local standards regulating air, water and land quality affect substantially all of our manufacturing locations.  Compliance with such laws and regulations has required and will continue to require capital expenditures and increase operating costs. Pursuant to our arrangement with Westlake, Westlake will indemnify us for liabilities that occurred or existed (in connection with compliance with such laws and regulations) prior to August 4, 2014.

It is our policy to comply with all environmental, health and safety requirements in the jurisdictions in which we and OpCo operate and to provide safe and environmentally sound workplaces for our employees. In some cases, compliance can be achieved only by incurring capital expenditures. In 2017 , OpCo incurred capital expenditures of $1.3 million related to environmental compliance. We estimate that OpCo will make capital expenditures of approximately $1.2 million in 2018 and $2.2 million in 2019 , respectively, related to environmental compliance.

Potential Flare Modifications . For several years, the Environmental Protection Agency ("EPA") has been conducting an enforcement initiative against petroleum refineries and petrochemical plants with respect to emissions from flares. On April 21, 2014, Westlake received a Clean Air Act Section 114 Information Request from the EPA which sought information regarding flares at the Calvert City and Lake Charles facilities. The EPA has informed Westlake that the information provided leads the EPA to believe that some of the flares are out of compliance with applicable standards. The EPA has indicated that it is seeking a consent decree that would obligate Westlake to take corrective actions relating to the alleged noncompliance. The Partnership believes the resolution of these matters may require the payment of a monetary sanction in excess of $100,000 .

Risk Management Program Investigation . Region 4 of the EPA has conducted inspections and information requests to assess compliance with Risk Management Program requirements under the Clean Air Act at the Calvert City, Kentucky facility.

EPA Region 4 has identified concerns with the facility’s compliance under the Risk Management Program and Release Prevention regulations in connection with certain emissions release events between 2011 and 2015. Westlake has engaged in communications with EPA Region 4 to resolve these concerns. The Partnership believes the resolution of these matters may require the payment of a monetary sanction in excess of $100,000.

Kentucky Notices of Violation . In October 2017, the Enforcement Division of Kentucky Department of Environmental Protection (KDEP) indicated that it intended to proceed with enforcement on two Notices of Violation (NOVs) received by the Calvert City, Kentucky facility in December 2016 and May 2017. The NOVs allege violations of state and federal air requirements in connection with the operation of the olefins unit at the facility. Westlake has engaged in negotiations with KDEP to resolve these alleged violations. The Partnership believes the resolution of these matters may require the payment of a monetary sanction in excess of $100,000.

In addition to the matters described above, the Partnership is involved in various legal proceedings incidental to the conduct of its business. The Partnership does not believe that any of these legal proceedings will have a material adverse effect on its financial condition, results of operations or cash flows.

Also, see the discussion of our environmental matters contained in Item 1A. "Risk Factors" and Item 3"—Legal Proceedings" below.

Employees

Neither we nor OpCo has any employees. Under the Services and Secondment Agreement with Westlake, Westlake seconds employees to OpCo to allow OpCo to operate its facilities. Such seconded employees are under OpCo's control while they work on OpCo's facilities. As of December 31, 2017 , 119 employees were seconded to OpCo. Of these, 21 are covered by collective bargaining agreements that expire on November 1, 2019. There have been no strikes or lockouts, and neither OpCo nor Westlake has experienced any work stoppages throughout its history. We believe that Westlake's relationship with the local union officials and bargaining committees is open and positive.

Legal Proceedings

In the ordinary conduct of our business, we and Westlake and our and Westlake's subsidiaries, including OpCo, are subject to periodic lawsuits, investigations and claims, including environmental claims and employee related matters. Although we cannot predict with certainty the ultimate resolution of lawsuits, investigations and claims asserted against us, we do not believe that any currently pending legal proceeding or proceedings to which we or Westlake or any of our or Westlake's subsidiaries, including OpCo, are a party will have a material adverse effect on our business, results of operations, cash flows or financial condition.

Competition

Due to the Ethylene Sales Agreement and integration with Westlake, OpCo does not directly compete with other ethylene producers for 95% of the planned volumes it produces. It is only on the 5% of planned ethylene volumes not sold to Westlake where OpCo competes with other regional merchant ethylene producers, including LyondellBasell Industries, N.V., Royal Dutch Shell, Williams Companies, BASF Corporation and Flint Hills Resources.

Available Information

We file annual, quarterly and current reports and other documents with the SEC under the Securities Exchange Act of 1934 (the "Exchange Act"). You may read and copy any materials we file with the SEC at the SEC's Public Reference Room at 100 F Street, NE, Washington, DC 20549. You may obtain information on the operations of the Public Reference Room by calling the SEC at (800) SEC-0330. In addition, the SEC maintains a website at www.sec.gov that contains reports and other information regarding issuers that file electronically with the SEC.

We also make available free of charge our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and any amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act, simultaneously with or as soon as reasonably practicable after filing such materials with, or furnishing such materials to, the SEC, and on or through our website, www.wlkpartners.com . The information on our website, or information about us on any other website, is not incorporated by reference into this report.

Item 1A. Risk Factors

Limited partner interests are inherently different from the capital stock of a corporation, although many of the business risks to which we are subject are similar to those that would be faced by a corporation engaged in a similar business. Security

holders and potential investors should carefully consider the following risk factors together with all of the other information included in this report. If any of the following risks were actually to occur, our business, financial condition, results of operations or cash flows could be materially adversely affected.

Risks Inherent in Our Business

We are substantially dependent on Westlake for our cash flows. If Westlake does not pay us under the terms of the Ethylene Sales Agreement or if our assets fail to perform as intended, we may not have sufficient cash from operations following the establishment of cash reserves and payment of costs and expenses, including cost reimbursements to our general partner and its affiliates, to enable us to pay the minimum quarterly distribution to our unitholders.

Currently, all of our cash flow is generated from cash distributions from OpCo, and a substantial majority of OpCo's cash flow is generated from payments by Westlake under the Ethylene Sales Agreement. Westlake's obligations to purchase ethylene under the Ethylene Sales Agreement may be temporarily suspended to the extent OpCo is unable to perform its obligations caused by any of certain events outside the reasonable control of OpCo. Such events include, for example, acts of God or calamities which affect the operation of OpCo's facilities; certain labor difficulties (whether or not the demands of the employees are within the power of OpCo to concede); and governmental orders or laws. In addition, Westlake is not obligated to purchase ethylene with respect to any period during which OpCo's facilities are not operating due to scheduled or unscheduled maintenance or turnarounds (which occur approximately every five years) other than under certain circumstances relating to the occurrence of force majeure. We expect that each of OpCo's facilities will have a turnaround once every five years and will not operate for typically between 25 and 45 days during each turnaround by itself. However, the duration of a turnaround by itself may be longer than expected or may cost more than originally estimated. Furthermore, expansions may also coincide with turnarounds, which may complicate and delay the completion of such turnarounds. A suspension of Westlake's obligations under the Ethylene Sales Agreement, including during periods where OpCo's facilities are not operating due to scheduled or unscheduled maintenance or turnarounds, would reduce OpCo's revenues and cash flows, and could materially adversely affect our ability to make distributions to our unitholders.

Westlake may be unable to generate enough cash flow from operations to meet its minimum obligations under the Ethylene Sales Agreement if its business is adversely impacted by competition, operational problems, general adverse economic conditions or the inability to obtain feedstock. For example, sustained lower prices of crude oil, such as the prices experienced since the third quarter of 2014 and continuing through 2017 (as of December 31, 2017, approximately 44% lower than their 2014 peak levels) may lead to lower margins for Westlake in the United States. If Westlake were unable to meet its minimum payment obligations to OpCo as a result of any one or more of these factors, our ability to make distributions to our unitholders would be reduced or eliminated. The level of payments made by Westlake will depend upon its ability to pay its minimum obligations under the Ethylene Sales Agreement and its ability and election to increase volumes above the minimums specified in the Ethylene Sales Agreement, which in turn are dependent upon, among other things, the level of production at Westlake's other facilities. If Westlake is unable to generate sufficient cash flow from its operations to meet its obligations, or otherwise defaults on its obligations, under the Ethylene Sales Agreement, OpCo will not have sufficient available cash to distribute to us to enable us to pay the minimum quarterly distribution, which will fluctuate from quarter to quarter based on the following factors, some of which are beyond our control:

to low crude oil prices or exports of natural gas liquids from the United States, for example), increased production of ethylene or export of ethane or ethylene from the United States;

In addition, the actual amount of cash we will have available for distribution will depend on other factors, including:

We will require a significant amount of cash to service our debt and OpCo's debt, including borrowings under our and OpCo's credit facilities with Westlake. Our ability to make payments on and refinance this debt will depend on our ability to generate cash in the future, which is subject to the same factors described above in connection with our ability to pay quarterly distributions to unitholders. Cash that is used to service debt will be unavailable for distributions to our unitholders.

OpCo is subject to the credit risk of Westlake on a substantial majority of its revenues, and Westlake's leverage and creditworthiness could adversely affect our ability to make distributions to our unitholders.

Our ability to make distributions to unitholders is substantially dependent on Westlake's ability to meet its minimum contractual obligations under the Ethylene Sales Agreement. If Westlake defaults on its obligations, our ability to make distributions to our unitholders would be reduced or eliminated. Westlake has not pledged any assets to us as security for the performance of its obligations.

Westlake has not agreed with us to limit its ability to incur indebtedness, pledge or sell assets or make investments, and we have no control over the amount of indebtedness Westlake incurs, the assets it pledges or sells or the investments it makes.

OpCo is a restricted subsidiary under Westlake's credit facility and the indentures governing its senior notes. Restrictions in the indentures could limit OpCo's ability to make distributions to us.

All of our cash is currently generated from cash distributions from OpCo. Westlake's credit facility and the indentures governing its senior notes impose significant operating and financial restrictions on OpCo. These restrictions limit OpCo's ability to:

In addition, the indentures governing Westlake's senior notes prevent OpCo from making distributions to us if any default or event of default (as defined in the indentures) exists.

These limitations are subject to a number of important qualifications and exceptions. However, the effectiveness of many of these restrictions in the indentures governing Westlake's senior notes is currently suspended under the indentures because the senior notes are currently rated investment grade by at least two nationally recognized credit rating agencies.

These covenants may adversely affect OpCo's ability to finance future business opportunities. A breach of any of these covenants could result in a default in respect of the related debt. If a default occurred, the relevant lenders could elect to declare the debt, together with accrued interest and other fees, to be immediately due and payable and proceed against any collateral securing that debt, including OpCo and its assets. In addition, any acceleration of debt under Westlake's credit facility will constitute a default under some of Westlake's other debt, including the indentures governing its senior notes

Substantially all of OpCo's sales are generated at three facilities located at two sites. Any adverse developments at any of these facilities or sites could have a material adverse effect on our results of operations and therefore our ability to distribute cash to unitholders.

OpCo's operations are subject to significant hazards and risks inherent in ethylene production operations. These hazards and risks include, but are not limited to, equipment malfunction, explosions, fires and the effects of severe weather conditions, any of which could result in production and transportation difficulties and disruptions, pollution, personal injury or wrongful death claims and other damage to our properties and the property of others. There is also risk of mechanical failure of OpCo's facilities both in the normal course of operations and following unforeseen events. Any adverse developments at any of OpCo's facilities could have a material adverse effect on our results of operations and therefore our ability to distribute cash to unitholders.

Because substantially all of OpCo's sales are generated at three facilities located at two sites, any such events at any facility or site could significantly disrupt OpCo's ethylene production and its ability to supply ethylene to its customers. Any sustained disruption in its ability to meet its supply obligations under the Ethylene Sales Agreement could have a material adverse effect on our results of operations and therefore our ability to distribute cash to unitholders.

The ethylene sales price charged under the Ethylene Sales Agreement is designed to permit OpCo to cover the substantial majority of its operating costs, but not our public partnership and other OpCo costs, which will reduce our net operating profit.

The purchase price under the Ethylene Sales Agreement is based on OpCo's actual ethane, other feedstock and natural gas costs and an annual estimate of other operating costs and maintenance capital expenditures and other turnaround expenditures. The price is designed to permit OpCo to recover the portion of its costs of feedstocks and other costs to operate the ethylene production facilities associated with the percentage of its production capacity purchased by Westlake and generate a fixed margin per pound of ethylene purchased by Westlake. The price is not designed to allow OpCo to recover any capital expenditures related to expansion (such as our plans to upgrade and expand the capacity of Petro 1 and our facility in Calvert City), or operational efficiency. The ethylene sales price also does not increase to cover our public partnership costs. Both of these costs reduce our net operating profit.

The fee structure of the Ethylene Sales Agreement may limit OpCo's ability to take advantage of favorable market developments in the future.

The Ethylene Sales Agreement sets a $0.10 per pound margin for a substantial majority of OpCo's ethylene production, limiting OpCo's ability to take advantage of potential decreased ethane and other feedstock prices, potential increased ethylene prices or other favorable market developments. Under these circumstances, OpCo may not be in a position to enable its partners, including us, to benefit from favorable market developments (including any potential ethylene price increase in the future) through increased distributions. In addition, under these circumstances, OpCo may be disadvantaged relative to those of its competitors that are in a better position to take advantage of favorable market developments.

If OpCo is unable to renew or extend the Ethylene Sales Agreement beyond the initial 12-year term or the other agreements with Westlake upon expiration of these agreements, our ability to make distributions in the future could be materially adversely affected and the value of our units could decline.

Westlake's obligations under the Ethylene Sales Agreement, the Feedstock Supply Agreement and the related services and secondment agreement will become terminable by either party commencing December 31, 2026. If OpCo were unable to reach agreement with Westlake on an extension or replacement of these agreements, then our ability to make distributions on our common units could be materially adversely affected and the value of our common units could decline.

OpCo has the right to use the real property underlying Lake Charles Olefins and Calvert City Olefins pursuant to two, 50-year site lease agreements with Westlake. If OpCo is not able to renew the site lease agreements or if the site lease agreements are terminated by Westlake, OpCo may have to relocate Lake Charles Olefins and Calvert City Olefins, abandon the assets or sell the assets to Westlake.

Westlake has (1) leased to OpCo the real property underlying Lake Charles Olefins and Calvert City Olefins and (2) granted OpCo rights to access and use certain other portions of Westlake's facilities that are necessary to operate OpCo's units at such facilities. The site lease agreements each have a term of 50 years and may be renewed if agreed to by the parties. If an event of default with respect to bankruptcy of OpCo occurs, if Westlake terminates the Ethylene Sales Agreement in accordance with its provisions either for cause or due to a force majeure event, or if OpCo ceases to operate Lake Charles Olefins or Calvert City Olefins for six consecutive months (other than due to force majeure or construction following a casualty loss), Westlake may terminate the applicable site lease following notice and expiration of a cure period to remedy the default. In addition, if OpCo fails to act in good faith to expeditiously restore Lake Charles Olefins or Calvert City Olefins following a casualty loss, Westlake has the ability to terminate the applicable site lease agreement, to restore Lake Charles Olefins or Calvert City Olefins, as the case may be, and to purchase such ethylene production facilities at fair market value. If OpCo is unable to renew the site lease agreements or if Westlake terminates one or both of the site lease agreements, OpCo may have to relocate Lake Charles Olefins and Calvert City Olefins, abandon the assets or sell the assets to Westlake, the result of which may have a material adverse effect on our business, results of operations and financial condition.

OpCo depends upon Westlake for numerous services and for its labor force.

Pursuant to a services and secondment agreement, Westlake is obligated to provide OpCo operating services, utility access services and other key site services. Westlake provides the services of certain of its employees, who act as OpCo's agents in operating and maintaining OpCo's ethylene production facilities. If this agreement is terminated or if Westlake or its affiliates fail to satisfactorily provide these services or employees, OpCo would be required to hire labor, provide these services internally or find a third-party provider of these services. Any services or labor OpCo chooses to provide internally may not be as cost effective as those that Westlake or its affiliates provide, particularly in light of OpCo's lack of experience as an independent organization. If OpCo is required to obtain these services or labor from a third party, it may be unable to do so in a timely, efficient and cost-effective manner, the services or labor it receives may be inferior to or more costly than those that Westlake is currently providing, or such services and labor may be unavailable. Moreover, given the integration of OpCo's ethylene production facilities and Westlake's Lake Charles and Calvert City facilities, it may not be practical for us or for a third party to provide site services or labor for OpCo's ethylene production facilities separately.

OpCo's ability to receive greater cash flows from increased production may be limited by the Ethylene Sales Agreement.

OpCo's ability to increase throughput volumes through its assets is constrained by the capacity limitations of those assets, which are currently operating at close to full capacity. OpCo's ability to increase its cash flow by selling ethylene to third parties may be limited by the Ethylene Sales Agreement. OpCo's ability to sell ethylene to third parties is limited to available excess capacity, since Westlake has the right to purchase the substantial majority of production from OpCo's facilities through its minimum purchase commitment and option to purchase additional ethylene under the Ethylene Sales Agreement. The Ethylene Sales Agreement provisions may prohibit OpCo from competing effectively for third party business for this excess

production given the limited volumes available for sale. For example, so long as Westlake is not in default under the Ethylene Sales Agreement, Westlake has the right to purchase 95% of OpCo's production in excess of planned capacity.

The amount of cash we have available for distribution to holders of our units depends primarily on our cash flow and not solely on profitability, which may prevent us from making cash distributions during periods when we record net income.

The amount of cash we have available for distribution depends primarily upon our cash flow, including cash flow from reserves and working capital or borrowings (including any under our credit facilities,) and not solely on profitability, which will be affected by non-cash items. As a result, we may pay cash distributions during periods when we record net losses for financial accounting purposes and may be unable to pay cash distributions during periods when we record net income. We may be unable to access our revolving credit facilities when we do not have sufficient cash flows to pay cash distributions.

If we are unable to make acquisitions from Westlake or third parties on economically acceptable terms, our future growth would be limited, and any acquisitions we make may reduce, rather than increase, our cash generated from operations on a per unit basis.

Our strategy to grow our business and increase distributions to unitholders is dependent on our ability to make acquisitions that result in an increase in our cash distributions per unit. If we are unable to make acquisitions of additional interests in OpCo from Westlake on acceptable terms or we are unable to obtain financing for these acquisitions, our future growth and ability to increase distributions will be limited. In addition, we may be unable to make acquisitions from third parties as an alternative avenue to growth. Furthermore, even if we do consummate acquisitions that we believe will be accretive, they may in fact result in a decrease in our cash distributions per unit. Any acquisition involves potential risks, some of which are beyond our control, including, among other things:

If we consummate any future acquisitions, our capitalization and results of operations may change significantly, and unitholders will not have the opportunity to evaluate the economic, financial and other relevant information that we will consider in determining the application of our funds and other resources.

Many of our assets have been in service for many years and require significant expenditures to maintain them. As a result, our maintenance or repair costs may increase in the future. In addition, while we intend to establish cash reserves in order to cover turnaround expenditures, the amounts we reserve may not be sufficient to fully cover such expenditures.

Many of the assets we use to produce ethylene are generally long-lived assets. As a result, some of those assets have been in service for many decades. The age and condition of these assets could result in increased maintenance or repair expenditures. In addition, while we intend to establish cash reserves in order to cover our turnaround expenditures, the amounts we reserve may be insufficient to fully cover such expenditures. Any significant and unexpected increase in these expenditures could adversely affect our results of operations, financial position or cash flows, as well as our ability to pay cash distributions.

Regulations concerning the transportation of hazardous chemicals and the security of chemical manufacturing facilities could result in higher operating costs.

Chemical manufacturing facilities may be at greater risk of terrorist attacks than other potential targets in the U.S. As a result, the chemicals industry responded to the issues surrounding the terrorist attacks of September 11, 2001 by starting initiatives relating to the security of chemicals industry facilities and the transportation of hazardous chemicals in the U.S. Simultaneously, local, state and federal governments began a regulatory process that led to new regulations impacting the security of chemical plant locations and the transportation of hazardous chemicals. Our business or our customers' businesses could be adversely affected because of the cost of complying with these regulations.

Our production facilities process volatile and hazardous materials that subject us to operating risks that could adversely affect our operating results.

Our operations are subject to the usual hazards associated with commodity chemical and plastics manufacturing and the related use, storage, transportation and disposal of feedstocks, products and wastes, including:

All these hazards can cause personal injury and loss of life, catastrophic damage to or destruction of property and equipment and environmental damage, and may result in a suspension of operations and the imposition of civil or criminal penalties. We could become subject to environmental claims brought by governmental entities or third parties. A loss or shutdown of operations over an extended period at any one of our three major operating facilities would have a material adverse effect on us. We maintain property, business interruption and casualty insurance that we believe is in accordance with customary industry practices, but we cannot be fully insured against all potential hazards incident to our business, including losses resulting from war risks or terrorist acts. As a result of market conditions, premiums and deductibles for certain insurance policies can increase substantially and, in some instances, certain insurance may become unavailable or available only for reduced amounts of coverage. If we were to incur a significant liability for which we were not fully insured, it could have a material adverse effect on our financial position.

Our operations and assets are subject to extensive environmental, health and safety laws and regulations.

We use hazardous substances and generate hazardous wastes and emissions in our manufacturing operations. Our industry is highly regulated and monitored by various environmental regulatory authorities such as the Environmental Protection Agency (the "EPA"). As such, we are subject to extensive federal, state and local laws and regulations pertaining to pollution and protection of the environment, health and safety, which govern, among other things, emissions to the air, discharges onto land or waters, the maintenance of safe conditions in the workplace, the remediation of contaminated sites, and the generation, handling, storage, transportation, treatment and disposal of waste materials. Some of these laws and regulations are subject to varying and conflicting interpretations. Many of these laws and regulations provide for substantial fines and potential criminal sanctions for violations and require the installation of costly pollution control equipment or operational changes to limit pollution emissions or reduce the likelihood or impact of hazardous substance releases, whether permitted or not. For example, our petrochemical facilities may require improvements to comply with certain changes in process safety management requirements.

Our operations produce greenhouse gas ("GHG") emissions, which have been the subject of increased scrutiny and regulation. The EPA has adopted rules requiring the reporting of GHG emissions from specified large GHG emission sources on an annual basis including our facilities in Lake Charles and Calvert City. Various jurisdictions have considered or adopted laws and regulations on GHG emissions, with the general aim of reducing such emissions. The EPA currently requires certain industrial facilities to report their GHG emissions, and to obtain permits with stringent control requirements before constructing or modifying new facilities with significant criteria pollutant and GHG emissions. As our chemical processing results in GHG emissions, these and other GHG laws and regulations could affect our costs of doing business.

We also may face liability for alleged personal injury or property damage due to exposure to chemicals or other hazardous substances at our facilities or to chemicals that we otherwise manufacture, handle or own. Although these types of claims have

not historically had a material impact on our operations, a significant increase in the success of these types of claims could have a material adverse effect on our business, financial condition, operating results or cash flow.

Environmental laws may have a significant effect on the nature and scope of, and responsibility for, cleanup of contamination at our current and former operating facilities, the costs of transportation and storage of raw materials and finished products, the costs of reducing emissions and the costs of the storage and disposal of wastewater. The U.S. Comprehensive Environmental Response, Compensation, and Liability Act ("CERCLA") and similar state laws impose joint and several liability for the costs of remedial investigations and actions on the entities that are deemed responsible for a release of hazardous substances into the environment, including entities that have generated hazardous substances or arranged for their transportation or disposal, as well as the past and present owners and operators of disposal sites. All such potentially responsible parties (or any one of them, including us) may be required to bear all of such costs regardless of fault, legality of the original disposal or ownership of the disposal site. In addition, CERCLA and similar state laws could impose liability for damages to natural resources caused by contamination.

Although we seek to take preventive action, our operations are inherently subject to accidental spills, discharges or other releases of hazardous substances that may make us liable to governmental entities or private parties. This may involve contamination associated with our current and former facilities, facilities to which we sent wastes or by-products for treatment or disposal and other contamination. Accidental discharges may occur in the future, future action may be taken in connection with past discharges, governmental agencies may assess damages or penalties against us in connection with any past or future contamination, or third parties may assert claims against us for damages allegedly arising out of any past or future contamination. In addition, we may be liable for existing contamination related to certain of our facilities for which, in some cases, we believe third parties are liable in the event such third parties fail to perform their obligations.

Failure to adequately protect critical data and technology systems could materially affect our operations.

Information technology system failures, network disruptions and breaches of data security could disrupt our operations by causing delays or cancellation of customer orders, impede the manufacture or shipment of products or cause standard business processes to become ineffective, resulting in the unintentional disclosure of information or damage to our reputation. While Westlake, which manages our security protocol under the omnibus agreement, has taken steps to address these concerns by implementing network security and internal control measures, there can be no assurance that a system failure, network disruption or data security breach will not have a material adverse effect on our business, financial condition, operating results or cash flow.

A terrorist attack or armed conflict could harm our business.

Terrorist activities, anti-terrorist efforts and other armed conflicts involving the U.S. or other jurisdictions could adversely affect the U.S. and global economies and could prevent us from meeting financial and other obligations. We could experience loss of business, delays or defaults in payments from customers or disruptions of fuel supplies and markets if North American and global utilities are direct targets or indirect casualties of an act of terror or war. Terrorist activities and the threat of potential terrorist activities and any resulting economic downturn could adversely affect our results of operations, impair our ability to raise capital or otherwise adversely impact our ability to realize certain business strategies.

Risks Relating to Our Partnership Structure

Westlake owns and controls our general partner, which has sole responsibility for conducting our business and managing our operations. Our general partner and its affiliates, including Westlake, may have conflicts of interest with us and have limited duties, and they may favor their own interests to our detriment and that of our unitholders.

Westlake owns and controls our general partner and appoints all of the directors of our general partner. Although our general partner has a duty to manage us in a manner that it believes is not adverse to our interests, the executive officers and directors of our general partner have a fiduciary duty to manage our general partner in a manner beneficial to Westlake. Therefore, conflicts of interest may arise between Westlake or any of its affiliates, including our general partner, on the one hand, and us or any of our unitholders, on the other hand. In resolving these conflicts of interest, our general partner may favor its own interests and the interests of its affiliates over the interests of our common unitholders. These conflicts include the following situations, among others:

In addition, we may compete directly with Westlake and entities in which it has an interest for acquisition opportunities and potentially will compete with these entities for new business or extensions of the existing services provided by us. Please read "Westlake and other affiliates of our general partner may compete with us."

The board of directors may modify or revoke our cash distribution policy at any time at its discretion. Our partnership agreement does not require us to pay any distributions at all.

The board of directors adopted a cash distribution policy pursuant to which we intend to distribute quarterly at least $0.2750 per unit on all of our units to the extent we have sufficient cash after the establishment of cash reserves and the payment of our expenses, including payments to our general partner and its affiliates. However, the board may change such policy at any time at its discretion and could elect not to pay distributions for one or more quarters.

In addition, our partnership agreement does not require us to pay any distributions at all. Accordingly, investors are cautioned not to place undue reliance on the permanence of such a policy in making an investment decision. Any modification or revocation of our cash distribution policy could substantially reduce or eliminate the amount we distribute to our unitholders. The amount of distributions we make, if any, and the decision to make any distribution at all will be determined by the board of directors, whose interests may differ from those of our common unitholders. Our general partner has limited duties to our unitholders, which may permit it to favor its own interests or the interests of Westlake to the detriment of our common unitholders.

Our general partner intends to limit its liability regarding our obligations.

Our general partner intends to limit its liability under contractual arrangements between us and third parties so that the counterparties to such arrangements have recourse only against our assets, and not against our general partner or its assets. Our general partner may therefore cause us to incur indebtedness or other obligations that are nonrecourse to our general partner. Our partnership agreement provides that any action taken by our general partner to limit its liability is not a breach of our general partner's duties, even if we could have obtained more favorable terms without the limitation on liability.

We expect to distribute a significant portion of our available cash to our partners, which could limit our ability to grow and make acquisitions.

We plan to distribute most of our available cash, which may cause our growth to proceed at a slower pace than that of businesses that reinvest their cash to expand ongoing operations. To the extent we issue additional units in connection with any acquisitions or expansion capital expenditures, the payment of distributions on those additional units may increase the risk that we will be unable to maintain or increase our per unit distribution level. There are no limitations in our partnership agreement on our ability to issue additional units, including units ranking senior to the common units. The incurrence of additional commercial borrowings or other debt to finance our growth strategy would result in increased interest expense, which, in turn, may impact the cash that we have available to distribute to our unitholders.

Our partnership agreement replaces our general partner's fiduciary duties to holders of our units.

Our partnership agreement contains provisions that eliminate and replace the fiduciary standards to which our general partner would otherwise be held by state fiduciary duty law. For example, our partnership agreement permits our general partner to make a number of decisions in its individual capacity, as opposed to in its capacity as our general partner, or otherwise free of fiduciary duties to us and our unitholders. This entitles our general partner to consider only the interests and factors that it desires and relieves it of any duty or obligation to give any consideration to any interest of, or factors affecting, us, our affiliates or our limited partners. Examples of decisions that our general partner may make in its individual capacity include:

By purchasing a common unit, a unitholder is treated as having consented to the provisions in the partnership agreement, including the provisions discussed above.

Our partnership agreement restricts the remedies available to holders of our units for actions taken by our general partner that might otherwise constitute breaches of fiduciary duty.

Our partnership agreement contains provisions that restrict the remedies available to unitholders for actions taken by our general partner that might otherwise constitute breaches of fiduciary duty under state fiduciary duty law. For example, our partnership agreement provides that:

In connection with a situation involving a transaction with an affiliate or a conflict of interest, other than one where our general partner is permitted to act in its sole discretion, any determination by our general partner must be made in good faith. If an affiliate transaction or the resolution of a conflict of interest is not approved by our common unitholders or the conflicts committee, then it will be presumed that, in making its decision, taking any action or failing to act, the board of directors acted in good faith, and in any proceeding brought by or on behalf of any limited partner or the partnership, the person bringing or prosecuting such proceeding will have the burden of overcoming such presumption.

Our partnership agreement provides that the conflicts committee of the board of directors may be comprised of one or more independent directors. If the board of directors establishes a conflicts committee with only one independent director, your interests may not be as well served as if the conflicts committee was comprised of at least two independent directors. A single-member conflicts committee would not have the benefit of discussion with, and input from, other independent directors.

Westlake and other affiliates of our general partner may compete with us.

Affiliates of our general partner, including Westlake, are not prohibited from engaging in other businesses or activities, including those that might be in direct competition with us. In addition, Westlake may compete with us for investment opportunities and may own an interest in entities that compete with us.

Pursuant to the terms of our partnership agreement, the doctrine of corporate opportunity, or any analogous doctrine, does not apply to our general partner or any of its affiliates, including its executive officers and directors and Westlake. Any such person or entity that becomes aware of a potential transaction, agreement, arrangement or other matter that may be an opportunity for us will not have any duty to communicate or offer such opportunity to us. Any such person or entity will not be liable to us or to any limited partner for breach of any fiduciary duty or other duty by reason of the fact that such person or entity pursues or acquires such opportunity for itself, directs such opportunity to another person or entity or does not communicate such opportunity or information to us. This may create actual and potential conflicts of interest between us and affiliates of our general partner and result in less than favorable treatment of us and our unitholders.

The holder or holders of our incentive distribution rights may elect to cause us to issue common units to it in connection with a resetting of the target distribution levels related to the incentive distribution rights, without the approval of the conflicts committee of our board of directors or the holders of our common units. This could result in lower distributions to holders of our common units.

The holder or holders of a majority of our incentive distribution rights (currently Westlake) have the right, at any time when there are no subordinated units outstanding and we have made cash distributions in excess of the then-applicable third target distribution for each of the prior four consecutive fiscal quarters, to reset the initial target distribution levels at higher levels based on our cash distribution levels at the time of the exercise of the reset election. Following a reset election by such holder or holders, the minimum quarterly distribution will be calculated equal to an amount equal to the prior cash distribution per common unit for the fiscal quarter immediately preceding the reset election (such amount is referred to as the "reset minimum quarterly distribution") and the target distribution levels will be reset to correspondingly higher levels based on percentage increases above the reset minimum quarterly distribution. If such holder or holders elects to reset the target distribution levels, they will be entitled to receive common units as consideration for such election. The number of common units to be issued to such holder or holders will equal the number of common units that would have entitled the holder to an aggregate quarterly cash distribution for the quarter prior to the reset election equal to the distribution on the incentive distribution rights for the quarter prior to the reset election.

Westlake, as the current holder of our incentive distribution rights, could exercise this reset right in order to facilitate acquisitions or internal growth projects that would not be sufficiently accretive to cash distributions per unit without such conversion. However, Westlake may transfer the incentive distribution rights at any time. It is possible that Westlake or a transferee could exercise this reset election at a time when we are experiencing declines in our aggregate cash distributions or at a time when the holders of the incentive distribution rights expect that we will experience declines in our aggregate cash distributions in the foreseeable future. In such situations, a holder of the incentive distribution rights may be experiencing, or may expect to experience, declines in the cash distributions it receives related to the incentive distribution rights and may therefore desire to be issued our common units rather than retain the right to receive incentive distributions based on the initial target distribution levels. As a result, a reset election may cause our common unitholders to experience reduction in the amount

of cash distributions that they would have otherwise received had we not issued new common units to the holders of the incentive distribution rights in connection with resetting the target distribution levels.

Holders of our common units have limited voting rights and are not entitled to elect our general partner or its directors, which could reduce the price at which our common units trade.

Compared to the holders of common stock in a corporation, unitholders have limited voting rights and, therefore, limited ability to influence management's decisions regarding our business. Unitholders will have no right on an annual or ongoing basis to elect our general partner or its board of directors. The board of directors, including the independent directors, is chosen entirely by Westlake, as a result of it owning our general partner, and not by our unitholders. Unlike publicly traded corporations, we will not conduct annual meetings of our unitholders to elect directors or conduct other matters routinely conducted at annual meetings of stockholders of corporations. As a result of these limitations, the price at which the common units trade could be diminished because of the absence or reduction of a takeover premium in the trading price.

Even if holders of our common units are dissatisfied, they cannot currently remove our general partner without its consent.

If our unitholders are dissatisfied with the performance of our general partner, they currently cannot remove our general partner. Unitholders currently are unable to remove our general partner without its consent because our general partner and its affiliates own sufficient units to be able to prevent its removal. The vote, including Westlake, of the holders of at least 66 ² / ₃ % of all outstanding common and subordinated units voting together as a single class is required to remove our general partner. As of February 22, 2018 , Westlake owned an aggregate of 43.8% of our common units. This condition provides Westlake the ability to prevent the removal of our general partner.

Control of our general partner may be transferred to a third party without unitholder consent.

Our general partner may transfer its general partner interest to a third party without the consent of our unitholders. Furthermore, our partnership agreement permits Westlake to transfer ownership of our general partner to a third party, also without the consent of our unitholders. The new owner of our general partner would then be in a position to replace the board of directors and executive officers of our general partner with its own designees and thereby exert significant control over the decisions taken by the board of directors and executive officers of our general partner. This effectively permits a "change of control" without the vote or consent of the unitholders.

The incentive distribution rights may be transferred to a third party without unitholder consent.

Westlake may transfer the incentive distribution rights to a third party at any time without the consent of our unitholders. If Westlake transfers the incentive distribution rights to a third party, it would not have the same incentive to grow our partnership and increase quarterly distributions to unitholders over time. For example, a transfer of incentive distribution rights by Westlake could reduce the likelihood of it accepting offers made by us relating to assets owned by Westlake, as it would have less of an economic incentive to grow our business, which in turn would impact our ability to grow our asset base.

Our general partner has a call right that may require unitholders to sell their common units at an undesirable time or price.

If at any time our general partner and its affiliates own more than 80% of the common units, our general partner will have the right, which it may assign to any of its affiliates or to us, but not the obligation, to acquire all, but not less than all, of the common units held by unaffiliated persons at a price equal to the greater of (1) the average of the daily closing price of the common units over the 20 trading days preceding the date three days before notice of exercise of the call right is first mailed and (2) the highest per-unit price paid by our general partner or any of its affiliates for common units during the 90-day period preceding the date such notice is first mailed. As a result, unitholders may be required to sell their common units at an undesirable time or price and may not receive any return or a negative return on their investment. Unitholders may also incur a tax liability upon a sale of their units. Our general partner is not obligated to obtain a fairness opinion regarding the value of the common units to be repurchased by it upon exercise of the limited call right. There is no restriction in our partnership agreement that prevents our general partner from causing us to issue additional common units and then exercising its call right. If our general partner exercised its limited call right, the effect would be to take us private and, if the units were subsequently deregistered, we would no longer be subject to the reporting requirements of the Securities Exchange Act of 1934, as amended, or the Exchange Act.

We may issue additional units without unitholder approval, which would dilute existing unitholder ownership interests.

Our partnership agreement does not limit the number of additional limited partner interests we may issue at any time without the approval of our unitholders. The issuance of additional common units or other equity interests of equal or senior rank will have the following effects:

The market price of our common units could be adversely affected by sales of substantial amounts of our common units in the public or private markets, including sales by Westlake or other large holders.

All of the subordinated units will convert into common units on a one-for-one basis at the end of the subordination period. Additionally, Westlake has registration rights with respect to the common units it holds. Sales by Westlake or other large holders of a substantial number of our common units in the public markets, or the perception that such sales might occur, could have a material adverse effect on the price of our common units or could impair our ability to obtain capital through an offering of equity securities.

Our partnership agreement restricts the voting rights of unitholders owning 20% or more of our common units.

Our partnership agreement restricts unitholders' voting rights by providing that any units held by a person or group that owns 20% or more of any class of units then outstanding, other than our general partner and its affiliates, their transferees and persons who acquired such units with the prior approval of the board of directors, cannot vote on any matter.

Cost reimbursements due to our general partner and Westlake for services provided to us or on our behalf will reduce our earnings and therefore our cash available for distribution to our unitholders. The amount and timing of such reimbursements will be determined by our general partner.

We are obligated under our partnership agreement to reimburse our general partner and its affiliates for all expenses they incur and payments they make on our behalf, including expenses we and OpCo will incur under the services and secondment agreement and the omnibus agreement. Our partnership agreement does not set a limit on the amount of expenses for which our general partner and its affiliates may be reimbursed. These expenses include all expenses incurred under the services and secondment agreement and the omnibus agreement, including salary, bonus, incentive compensation and other amounts paid to persons who perform services for us or on our behalf and expenses allocated to our general partner by its affiliates. Our partnership agreement provides that our general partner will determine the expenses that are allocable to us. The reimbursement of expenses and payment of fees, if any, to our general partner and its affiliates will reduce the amount of our earnings and, thereby, our ability to distribute cash to our unitholders.

Unitholders may have liability to repay distributions.

Under certain circumstances, unitholders may have to repay amounts wrongfully returned or distributed to them. Under Section 17-607 of the Delaware Revised Uniform Limited Partnership Act, or the Delaware Act, we may not make a distribution to our unitholders if the distribution would cause our liabilities to exceed the fair value of our assets. Delaware law provides that for a period of three years from the date of the impermissible distribution, limited partners who received the distribution and who knew at the time of the distribution that it violated Delaware law will be liable to the limited partnership for the distribution amount. Liabilities to partners on account of their partnership interests and liabilities that are non-recourse to the partnership are not counted for purposes of determining whether a distribution is permitted.

If we fail to maintain an effective system of internal controls, we may not be able to accurately report our financial results or prevent fraud. As a result, current and potential unitholders could lose confidence in our financial reporting, which would harm our business and the trading price of our units.

Effective internal controls are necessary for us to provide reliable financial reports, prevent fraud and operate successfully as a public company. If we cannot provide reliable financial reports or prevent fraud, our reputation and operating results would be harmed. We cannot be certain that our efforts to maintain our internal controls will be successful, that we will be able to maintain adequate controls over our financial processes and reporting in the future or that we will be able to comply with our obligations under Section 404 of Sarbanes-Oxley. Any failure to maintain effective internal controls, or difficulties encountered

in implementing or improving our internal controls, could harm our operating results or cause us to fail to meet our reporting obligations. Ineffective internal controls could also cause investors to lose confidence in our reported financial information, which would likely have a negative effect on the trading price of our units.

Tax Risks to Common Unitholders

Our tax treatment depends on our status as a partnership for federal income tax purposes, and not being subject to a material amount of entity-level taxation. If the Internal Revenue Service ("IRS"), were to treat us as a corporation for federal income tax purposes, or we become subject to entity-level taxation for state tax purposes, our cash available for distribution to our unitholders would be substantially reduced.

The anticipated after-tax economic benefit of an investment in our common units depends largely on our being treated as a partnership for federal income tax purposes.

Despite the fact that we are organized as a limited partnership under Delaware law, we would be treated as a corporation for U.S. federal income tax purposes unless we satisfy a "qualifying income" requirement (the "Qualifying Income Exception") under Section 7704 of the Internal Revenue Code of 1986, as amended (the "Code"). Failure to meet the Qualifying Income Exception would cause us to be treated as a corporation for U.S. federal income tax purposes. Based upon our current operations, we believe we satisfy the qualifying income requirement.

Prior to our initial public offering, we requested and obtained a favorable private letter ruling from the IRS to the effect that, based on facts presented in the private letter ruling request, our income from the production, transportation, storage and marketing of ethylene and its co-products constitutes "qualifying income" within the meaning of Section 7704 of the Code. However, no ruling has been or will be requested regarding our treatment as a partnership for U.S. federal income tax purposes. Failure to meet the qualifying income requirement or a change in current law could cause us to be treated as a corporation for U.S. federal income tax purposes or otherwise subject us to taxation as an entity.

If we were treated as a corporation for federal income tax purposes, we would pay U.S. federal income tax on our taxable income at the corporate tax rate. Distributions to our unitholders would generally be taxed again as corporate distributions, and no income, gains, losses or deductions would flow through to our unitholders. Because a tax would be imposed upon us as a corporation, our cash available for distribution to our unitholders would be substantially reduced. Therefore, treatment of us as a corporation would result in a material reduction in the anticipated cash flow and after-tax return to our unitholders, likely causing a substantial reduction in the value of our common units.

Our partnership agreement provides that if a law is enacted or existing law is modified or interpreted in a manner that subjects us to taxation as a corporation or otherwise subjects us to entity-level taxation for U.S. federal, state, local or foreign income tax purposes, the minimum quarterly distribution amount and the target distribution amounts may be adjusted to reflect the impact of that law or interpretation on us. At the state level, several states have been evaluating ways to subject partnerships to entity-level taxation through the imposition of state income, franchise or other forms of taxation. Specifically, we currently own assets and conduct business in Louisiana, Kentucky and Texas. Texas and Kentucky impose entity-level franchise or gross receipt taxes on partnerships. In the future, we may expand our operations. Imposition of similar entity-level taxes on us in Louisiana or other jurisdictions that we may expand to could substantially reduce our cash available for distribution to you.

The tax treatment of publicly traded partnerships or an investment in our units could be subject to potential legislative, judicial or administrative changes or differing interpretations, possibly applied on a retroactive basis.

The present U.S. federal income tax treatment of publicly traded partnerships, including us, or an investment in our common units may be modified by administrative, legislative or judicial changes or differing interpretations at any time. From time to time, members of Congress propose and consider substantive changes to the existing U.S. federal income tax laws that affect publicly traded partnerships. Although there is no current legislative proposal, a prior legislative proposal would have eliminated the qualifying income exception to the treatment of all publicly-traded partnerships as corporations upon which we rely for our treatment as a partnership for U.S. federal income tax purposes.

In addition, on January 24, 2017, final regulations regarding which activities give rise to qualifying income within the meaning of Section 7704 of the Code (the "Final Regulations") were published in the Federal Register. The Final Regulations, consistent with our private letter ruling, treat our income from the production, transportation, storage and marketing of ethylene and its co-products constitutes as "qualifying income". However, there can be no assurance that there would not be further changes to the Treasury Department's interpretation of the qualifying income rules in a manner that could impact our ability to qualify as a partnership in the future.

Any modification to the U.S. federal income tax laws may be applied retroactively and could make it more difficult or impossible for us to meet the exception for certain publicly traded partnerships to be treated as partnerships for U.S. federal

income tax purposes. We are unable to predict whether any of these changes or other proposals will ultimately be adopted or enacted. Any similar or future legislative or administrative changes could negatively impact the value of an investment in our common units.

If the IRS were to contest the federal income tax positions we take, it may adversely impact the market for our common units, and the costs of any such contest would reduce our cash available for distribution to our unitholders.

The IRS may adopt positions that differ from the positions we take. It may be necessary to resort to administrative or court proceedings to sustain some or all of the positions we take. A court may not agree with some or all of the positions we take. Any contest with the IRS may materially and adversely impact the market for our common units and the price at which they trade. Moreover, the costs of any contest between us and the IRS will result in a reduction in our cash available for distribution to our unitholders and thus will be borne indirectly by our unitholders.

If the IRS makes audit adjustments to our income tax returns for tax years beginning after December 31, 2017, it (and some states) may assess and collect any taxes (including any applicable penalties and interest) resulting from such audit adjustments directly from us, in which case our cash available for distribution to our unitholders might be substantially reduced and our current and former unitholders may be required to indemnify us for any taxes (including any applicable penalties and interest) resulting from such audit adjustments that were paid on such unitholders behalf.

Pursuant to the Bipartisan Budget Act of 2015, for tax years beginning after December 31, 2017, if the IRS makes audit adjustments to our income tax returns, it (and some states) may assess and collect any taxes (including any applicable penalties and interest) resulting from such audit adjustments directly from us. To the extent possible under the new rules, our general partner may elect to either pay the taxes (including any applicable penalties and interest) directly to the IRS or, if we are eligible, issue a revised Schedule K-1 to each unitholder and former unitholder with respect to an audited and adjusted return. Although our general partner may elect to have our unitholders and former unitholders take such audit adjustment into account and pay any resulting taxes (including applicable penalties or interest) in accordance with their interests in us during the tax year under audit, there can be no assurance that such election will be practical, permissible or effective in all circumstances. As a result, our current unitholders may bear some or all of the tax liability resulting from such audit adjustment, even if such unitholders did not own units in us during the tax year under audit. If, as a result of any such audit adjustment, we are required to make payments of taxes, penalties and interest, our cash available for distribution to our unitholders might be substantially reduced and our current and former unitholders may be required to indemnify us for any taxes (including any applicable penalties and interest) resulting from such audit adjustments that were paid on such unitholders behalf. These rules are not applicable for tax years beginning on or prior to December 31, 2017.

Even if unitholders do not receive any cash distributions from us, unitholders will be required to pay taxes on their share of our taxable income, including their share of income from the cancellation of debt.

Unitholders are required to pay federal income taxes and, in some cases, state and local income taxes, on unitholders’ share of our taxable income, whether or not they receive cash distributions from us. Unitholders may not receive cash distributions from us equal to their share of our taxable income or even equal to the actual tax due from them with respect to that income.

Tax gain or loss on the disposition of our common units could be more or less than expected.

If a unitholder sells common units, the unitholder will recognize a gain or loss equal to the difference between the amount realized and that unitholder’s tax basis in those common units. Because distributions in excess of a unitholder’s allocable share of our net taxable income decrease such unitholder’s tax basis in its common units, the amount, if any, of such prior excess distributions with respect to the units a unitholder sells will, in effect, become taxable income to a unitholder if it sells such units at a price greater than its tax basis in those units, even if the price such unitholder receives is less than its original cost. In addition, because the amount realized includes a unitholder’s share of our nonrecourse liabilities, if a unitholder sells its units, a unitholder may incur a tax liability in excess of the amount of cash received from the sale.

A substantial portion of the amount realized from a unitholder’s sale of our units, whether or not representing gain, may be taxed as ordinary income to such unitholder due to potential recapture items, including depreciation recapture.  Thus, a unitholder may recognize both ordinary income and capital loss from the sale of units if the amount realized on a sale of such units is less than such unitholder’s adjusted basis in the units.  Net capital loss may only offset capital gains and, in the case of individuals, up to $3,000 of ordinary income per year.  In the taxable period in which a unitholder sells its units, such unitholder may recognize ordinary income from our allocations of income and gain to such unitholder prior to the sale and from recapture items that generally cannot be offset by any capital loss recognized upon the sale of units. 

Unitholders may be subject to limitation on their ability to deduct interest expense incurred by us.

In general, we are entitled to a deduction for interest paid or accrued on indebtedness properly allocable to our trade or business during our taxable year. However, under the Tax Cuts and Jobs Act enacted on December 22, 2017, for taxable years beginning after December 31, 2017, our deduction for “business interest” is limited to the sum of our business interest income and 30% of our “adjusted taxable income.” For the purposes of this limitation, our adjusted taxable income is computed without regard to any business interest expense or business interest income, and in the case of taxable years beginning before January 1, 2022, any deduction allowable for depreciation, amortization, or depletion.

Tax-exempt entities face unique tax issues from owning our common units that may result in adverse tax consequences to them .

Investment in our common units by tax-exempt entities, such as employee benefit plans and individual retirement accounts (known as IRAs) raises issues unique to them. For example, virtually all of our income allocated to organizations that are exempt from U.S. federal income tax, including IRAs and other retirement plans, will be unrelated business taxable income and will be taxable to them. Further, with respect to taxable years beginning after December 31, 2017, a tax-exempt entity with more than one unrelated trade or business (including by attribution from investment in a partnership such as ours that is engaged in one or more unrelated trade or business) is required to compute the unrelated business taxable income of such tax-exempt entity separately with respect to each such trade or business (including for purposes of determining any net operating loss deduction). As a result, for years beginning after December 31, 2017, it may not be possible for tax-exempt entities to utilize losses from an investment in our partnership to offset unrelated business taxable income from another unrelated trade or business and vice versa. Tax-exempt entities should consult a tax advisor before investing in our common units.

Non-U.S. Unitholders will be subject to U.S. taxes and withholding with respect to their income and gain from owning our units.

Non-U.S. unitholders are generally taxed and subject to income tax filing requirements by the United States on income effectively connected with a U.S. trade or business (“effectively connected income”). Income allocated to our unitholders and any gain from the sale of our units will generally be considered to be “effectively connected” with a U.S. trade or business.  As a result, distributions to a Non-U.S. unitholder will be subject to withholding at the highest applicable effective tax rate and a Non-U.S. unitholder who sells or otherwise disposes of a unit will also be subject to U.S. federal income tax on the gain realized from the sale or disposition of that unit. 

The Tax Cuts and Jobs Act imposes a withholding obligation of 10% of the amount realized upon a Non-U.S. unitholder’s sale or exchange of an interest in a partnership that is engaged in a U.S. trade or business. However, due to challenges of administering a withholding obligation applicable to open market trading and other complications, the IRS has temporarily suspended the application of this withholding rule to open market transfers of interests in publicly traded partnerships pending promulgation of regulations or other guidance that resolves the challenges.  It is not clear if or when such regulations or other guidance will be issued.  Non-U.S. unitholders should consult a tax advisor before investing in our common units.

We treat each purchaser of our common units as having the same tax benefits without regard to the common units actually purchased. The IRS may challenge this treatment, which could adversely affect the value of our common units.

Because we cannot match transferors and transferees of common units, we have adopted certain methods for allocating depreciation and amortization deductions that may not conform to all aspects of existing Treasury Regulations. A successful IRS challenge to the use of these methods could adversely affect the amount of tax benefits available to our unitholders. It also could affect the timing of these tax benefits or the amount of gain from any sale of common units and could have a negative impact on the value of our common units or result in audit adjustments to a unitholder’s tax returns.

We generally prorate our items of income, gain, loss and deduction between transferors and transferees of our units each month based upon the ownership of our units on the first day of each month, instead of on the basis of the date a particular unit is transferred. The IRS may challenge this treatment, which could change the allocation of items of income, gain, loss and deduction among our unitholders.

We generally prorate our items of income, gain, loss and deduction between transferors and transferees of our units each month based upon the ownership of our units on the first day of each month (the “Allocation Date”), instead of on the basis of the date a particular unit is transferred. Similarly, we generally allocate certain deductions for depreciation of capital additions, gain or loss realized on a sale or other disposition of our assets and, in the discretion of the general partner, any other extraordinary item of income, gain, loss or deduction based upon ownership on the Allocation Date. Treasury Regulations allow a similar monthly simplifying convention, but such regulations do not specifically authorize all aspects of our proration

method. If the IRS were to challenge our proration method, we may be required to change the allocation of items of income, gain, loss and deduction among our unitholders.

A unitholder whose units are the subject of a securities loan (e.g., a loan to a “short seller” to cover a short sale of units) may be considered to have disposed of those units. If so, such unitholder would no longer be treated for tax purposes as a partner with respect to those units during the period of the loan and may recognize gain or loss from the disposition.

Because there are no specific rules governing the U.S. federal income tax consequence of loaning a partnership interest, a unitholder whose units are the subject of a securities loan may be considered to have disposed of the loaned units. In that case, the unitholder may no longer be treated for tax purposes as a partner with respect to those units during the period of the loan to the short seller and the unitholder may recognize gain or loss from such disposition. Moreover, during the period of the loan, any of our income, gain, loss or deduction with respect to those units may not be reportable by the unitholder and any cash distributions received by the unitholder as to those units could be fully taxable as ordinary income. Unitholders desiring to assure their status as partners and avoid the risk of gain recognition from a securities loan are urged to consult a tax advisor to determine whether it is advisable to modify any applicable brokerage account agreements to prohibit their brokers from borrowing their units.

We have adopted certain valuation methodologies in determining a unitholder’s allocations of income, gain, loss and deduction. The IRS may challenge these methodologies or the resulting allocations, which could adversely affect the value of our common units.

In determining the items of income, gain, loss and deduction allocable to our unitholders, we must routinely determine the fair market value of our assets. Although we may, from time to time, consult with professional appraisers regarding valuation matters, we make many fair market value estimates using a methodology based on the market value of our common units as a means to measure the fair market value of our assets. The IRS may challenge these valuation methods and the resulting allocations of income, gain, loss and deduction.

A successful IRS challenge to these methods or allocations could adversely affect the timing or amount of taxable income or loss being allocated to our unitholders. It also could affect the amount of gain recognized from the sale of our common units, have a negative impact on the value of our common units or result in audit adjustments to our unitholders’ tax returns without the benefit of additional deductions.

Our unitholders will likely be subject to state and local taxes and income tax return filing requirements in jurisdictions where they do not live as a result of investing in our common units.

In addition to U.S. federal income taxes, our unitholders may be subject to other taxes, including foreign, state and local taxes, unincorporated business taxes and estate, inheritance or intangible taxes that are imposed by the various jurisdictions in which we conduct business or own property now or in the future, even if they do not live in any of those jurisdictions. Our unitholders will likely be required to file foreign, state and local income tax returns and pay state and local income taxes in some or all of these various jurisdictions. Further, our unitholders may be subject to penalties for failure to comply with those requirements.

We currently own assets and conduct business in Kentucky, Louisiana and Texas. Kentucky and Louisiana currently impose a personal income tax on individuals, Kentucky and Texas impose an entity-level franchise or gross receipts tax on a variety of legal entities, and Kentucky and Louisiana impose a corporate income tax on corporations and other entities treated as corporations for federal income tax purposes. As we make acquisitions or expand our business, we may own assets or conduct business in additional states that impose similar taxes. It is your responsibility to file all U.S. federal, foreign, state and local tax returns.

Item 1B. Unresolved Staff Comments

None.

Item 2. Properties

Information regarding our properties is contained in "Item 1. Business—OpCo's Assets" and "Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations."

Item 3. Legal Proceedings

In the ordinary conduct of our business, we and Westlake and Westlake's subsidiaries, including OpCo, are subject to periodic lawsuits, investigations and claims, including environmental claims and employee related matters. See the discussion

of our environmental matters contained in Item 1. "Business — Environmental" and Note 15 " — Commitments and Contingencies ", to the consolidated financial statements within this report. Although we cannot predict with certainty the ultimate resolution of lawsuits, investigations and claims asserted against us, we do not believe that any currently pending legal proceeding or proceedings to which we or Westlake or any of our or Westlake's subsidiaries, including OpCo, are a party will have a material adverse effect on our business, results of operations, cash flows or financial condition. In addition, under the Omnibus Agreement, Westlake agreed to indemnify OpCo for certain environmental liabilities arising out of or occurring before the closing date of the IPO.

Item 4. Mine Safety Disclosure

Not Applicable.