Items 1 and 2. BUSINESS AND PROPERTIES

ORGANIZATIONAL STRUCTURE

Phillips 66 Partners LP, headquartered in Houston, Texas, is a Delaware limited partnership formed in 2013 by Phillips 66 Company and Phillips 66 Partners GP LLC (our General Partner), both wholly owned subsidiaries of Phillips 66. On July 26, 2013, we completed our initial public offering, and our common units trade on the New York Stock Exchange (NYSE) under the symbol PSXP. On August 1, 2015, Phillips 66 Company transferred all of its limited partner interest in us and its 100 percent interest in our General Partner to its wholly owned subsidiary, Phillips 66 Project Development Inc. (Phillips 66 PDI). As of December 31, 2018 , Phillips 66, through Phillips 66 PDI, owned 68,760,137 common units, representing a 54 percent limited partner interest, as well as a 100 percent interest in our General Partner, which owned 2,480,051 general partner units, representing a 2 percent general partner interest. The public owned 55,343,918 common units, representing a 44 percent limited partner interest, and owned 13,819,791 perpetual convertible preferred units.

We are a growth-oriented master limited partnership formed to own, operate, develop and acquire primarily fee-based crude oil, refined petroleum products and natural gas liquids (NGL) transportation, processing, terminaling and storage facilities and systems. We are managed and operated by the executive officers of our General Partner, with oversight provided by its Board of Directors. Neither we nor our subsidiaries have any employees. Our General Partner has the sole responsibility for providing the employees and other personnel necessary to conduct our operations.

We primarily generate revenue by providing fee-based transportation, processing, terminaling, storage and NGL fractionation services to Phillips 66 and other customers. Our equity affiliates primarily generate revenue from transporting and terminaling NGL, refined petroleum products and crude oil. Since we do not own any of the NGL, crude oil and refined petroleum products we handle and do not engage in the trading of NGL, crude oil and refined petroleum products, we have limited direct exposure to risks associated with fluctuating commodity prices, although these risks indirectly influence our activities and results of operations over the long term.

We have entered into long-term, fee-based commercial agreements with Phillips 66 to provide transportation, terminaling, storage, stevedoring, fractionation, processing, and rail terminal services. Under these agreements, Phillips 66 commits to provide us with minimum transportation, throughput or storage volumes, or minimum monthly service fees. If Phillips 66 does not meet its minimum volume commitments, Phillips 66 pays us deficiency payments based on the calculations described in the agreements. We believe these agreements promote stable and predictable cash flows, and they are the source of a substantial portion of our revenue. We also have several other agreements with Phillips 66, including an amended omnibus agreement and an operational services agreement. See Note 21—Related Party Transactions , in the Notes to Consolidated Financial Statements, for a summary of all related party agreements.

Our operations are all conducted in the United States and comprise one reportable segment. See Item 8. Financial Statements and Supplementary Data, for financial information on our operations and assets.

2018 DEVELOPMENTS

We are constructing the Gray Oak Pipeline system, which will provide crude oil transportation from the Permian Basin and Eagle Ford to destinations in Corpus Christi and Freeport markets on the Texas Gulf Coast, including the Phillips 66 Sweeny Refinery. Supported by customer commitments, capacity of the pipeline will be 900,000 barrels per day (BPD). At December 31, 2018, we had an effective ownership interest in the pipeline system of 48.75 percent. In February 2019, another party exercised its option to acquire an interest in the pipeline system that reduced our effective ownership interest to 42.25 percent. The Gray Oak Pipeline system is anticipated to be in service by the end of 2019.

In Corpus Christi, the Gray Oak Pipeline will connect to multiple terminals, including the new South Texas Gateway Terminal under development by a co-venturer. The marine terminal is planned to have two deepwater docks and storage capacity of 6.5 to 7 million barrels. It is expected to begin operations by mid-2020. We own a 25 percent interest in the terminal.

We are constructing a 25,000-BPD isomerization unit at the Phillips 66 Lake Charles Refinery to increase production of higher-octane gasoline blend components. The project includes a long-term agreement with Phillips 66 for processing services with a minimum volume commitment. Completion is expected in the third quarter of 2019.

The Bayou Bridge Pipeline operates from Nederland, Texas, to Lake Charles, Louisiana. An extension of the pipeline from Lake Charles to St. James, Louisiana, is expected to be in service in March 2019. We own a 40 percent interest in the joint venture.

The Sand Hills Pipeline expansion was completed in the fourth quarter of 2018, increasing the capacity to 485,000 BPD. The pipeline transports natural gas liquids (NGL) from the Permian Basin and Eagle Ford to the Texas Gulf Coast. We own a 33.34 percent interest in the joint venture.

In connection with Phillips 66’s project to add NGL fractionation capacity at the Sweeny Hub, we are increasing storage capacity at Clemens Caverns from 9 million barrels to 15 million barrels. The caverns project is expected to be completed in late 2020.

We are expanding the Sweeny to Pasadena Pipeline by 80,000 BPD. In addition, product storage capacity will be increased by 300,000 barrels at the Pasadena Terminal and new connectivity will be added to third-party terminals. The project is expected to be completed in the second quarter of 2020.

We are constructing a new pipeline that will connect storage in Lake Charles, Louisiana, to our Clifton Ridge Marine Terminal. This connection is expected to enable additional product exports of up to 50,000 BPD from the Phillips 66 Lake Charles Refinery. The project is backed by a long-term agreement with Phillips 66 that includes a minimum volume commitment. The pipeline is expected to be completed in the second quarter of 2019.

The following table presents certain information regarding our equity investment pipeline assets as of December 31, 2018 .

The following table presents certain information regarding our equity investment terminal, rail rack and storage assets as of December 31, 2018 .

*Active terminaling capacity represents the amount of railcar loading capacity currently available for use by our customers.

*Marine capacity is in thousands of barrels per hour.

Processing Assets

The following table presents certain information regarding our other wholly owned assets as of December 31, 2018 . Each asset listed below has an associated commercial agreement with Phillips 66.

COMMERCIAL AND OTHER AGREEMENTS WITH PHILLIPS 66

Many of our assets are physically connected to, and integral to the operations of, Phillips 66’s wholly owned Alliance, Bayway, Billings, Ferndale, Lake Charles, Ponca City and Sweeny refineries and its jointly owned Borger and Wood River refineries. We have entered into multiple commercial agreements with Phillips 66, which include minimum volume commitments and inflation escalators. These agreements are the source of a significant portion of our revenue. Under these long-term, fee-based agreements, we provide transportation, terminaling, storage, stevedoring, fractionation and processing services to Phillips 66, and Phillips 66 commits to provide us with minimum quarterly volumes of crude oil, refined petroleum products and NGL or minimum monthly capacity or service fees.

See Note 21—Related Party Transactions , in the Notes to Consolidated Financial Statements, for summaries of the terms of commercial and other agreements with Phillips 66.

COMPETITION

Many of our assets are subject to contractual relationships with Phillips 66 under our commercial agreements and are directly connected to Phillips 66’s owned or operated refineries. As a result, we believe that we will not face significant competition from other pipelines, terminals, storage facilities, rail racks, fractionators and processing units for Phillips 66’s transportation and terminaling requirements to and from the refineries we support. If Phillips 66’s customers were to reduce their purchases of refined petroleum products, Phillips 66 might only ship the minimum volumes through our pipelines (or pay the shortfall payment if it does not ship the minimum volumes), which would cause a decrease in our revenue. Phillips 66 competes with integrated petroleum companies, which have their own crude oil supplies and distribution and marketing systems, as well as with independent refiners, many of which also have their own distribution and marketing systems. Phillips 66 also competes with other suppliers that purchase refined petroleum products for resale. Many of the entities in which we hold equity investments compete with other interstate and intrastate pipelines, rail and truck fleet operations, including those affiliated with major integrated petroleum and petrochemical companies, in terms of transportation fees, reliability and quality of customer service. Competition in any particular geographic area is significantly affected by the volume of products produced by refineries in that area, the volume of crude oil and natural gas liquids gathered and transported, and the availability of products and the cost of transportation to that area from distant locations.

RATES AND SAFETY REGULATIONS

Pipeline Rates

Our common carrier pipeline systems are subject to regulation by various federal, state and local agencies. The Federal Energy Regulatory Commission (FERC) regulates interstate transportation on our common carrier pipeline systems under the Interstate Commerce Act (ICA), the Energy Policy Act of 1992 (EPAct 1992) and the rules and regulations promulgated under those laws. FERC regulations require that rates for interstate service pipelines that transport crude oil and refined petroleum products (collectively referred to as “petroleum pipelines”) and certain other liquids be just and reasonable and must not be unduly discriminatory or confer any undue preference upon any shipper. FERC regulations also require interstate common carrier petroleum pipelines to file with FERC and publicly post tariffs stating their interstate transportation rates and terms and conditions of service. Under the ICA, FERC or interested persons may challenge existing or changed rates or services. FERC is authorized to investigate such changes and may suspend the effectiveness of a new rate for up to seven months. A successful rate challenge could result in a common carrier paying refunds together with interest for the period the rate was in effect. FERC may also order a pipeline to change its rates and may require a common carrier to pay shippers reparations for damages sustained for a period up to two years prior to the filing of a complaint. EPAct 1992 deemed certain interstate petroleum pipeline rates then in effect to be just and reasonable under the ICA. These rates are commonly referred to as “grandfathered rates.” Our rates in effect at the time of the passage of EPAct 1992 for interstate transportation service were deemed just and reasonable and therefore are grandfathered rates. New rates have been established subsequent to EPAct 1992 for certain of our pipeline systems. FERC may change grandfathered rates upon complaint only after it is shown that:

EPAct 1992 required FERC to establish a simplified methodology to adjust non-market-based tariff rates for inflation for interstate petroleum pipelines. As a result, FERC adopted an indexing rate methodology which, as currently in effect, allows common carriers to change their rates within prescribed ceiling levels that are tied to changes in the Producer Price Index (PPI) for finished goods. FERC’s indexing methodology is subject to review every five years. The indexing methodology is applicable to existing rates, including grandfathered rates, with the exclusion of market-based rates. In December 2015, FERC issued a Final Order concluding its five-year review of the indexing methodology.  FERC established an index level permitting annual adjustment of an indexed ceiling by PPI for finished goods plus 1.23 percent for the five-year period commencing July 1, 2016, and ending June 30, 2021. A pipeline is not required to increase its rates up to the indexed ceiling but is permitted to do so. Rate increases made under the index are presumed to be just and reasonable unless a protesting party can demonstrate that the portion of the rate increase resulting from application of the index is substantially in excess of the pipeline’s increase in costs. Under the indexing rate methodology, in any year in which the index is negative, pipelines must file to lower their rates if those rates would otherwise be above the rate ceiling. On October 20, 2016, FERC issued an Advance Notice of Proposed Rulemaking. FERC is seeking comment on a number of proposals, including: (1) whether FERC should deny any increase in a rate ceiling or an annual index-based rate increase if a pipeline’s revenues exceed total costs by 15 percent for the prior 2 years; (2) a new percentage comparison test that would deny a proposed increase to a pipeline’s rate or ceiling level greater than 5 percent above the barrel-mile cost changes; and (3) a requirement that all pipelines file indexed ceiling levels annually, with the ceiling levels subject to challenge and restricting the pipeline’s ability to carry forward the full indexed increase to a future period. FERC has not taken any further action on this matter.

While common carriers often use the indexing methodology to change their rates, they may elect to support proposed rates by using other methodologies such as cost-of-service rate making, market-based rates and settlement rates. A pipeline can follow a cost-of-service approach when seeking to increase its rates above the rate ceiling (or when seeking to avoid lowering rates to the reduced rate ceiling). A common carrier can charge market-based rates if it establishes that it lacks significant market power in the affected markets. In addition, a common carrier can establish rates under settlement if agreed upon by all current shippers. We primarily use indexed rates and settlement rates for our different pipeline systems.

Intrastate services provided by certain of our pipeline systems are subject to regulation by state regulatory authorities. These state regulatory authorities use a complaint-based system of regulation, both as to matters involving rates and priority of access. State regulatory authorities could limit our ability to increase our rates or to set rates based on our costs or order us to reduce our rates and require the payment of refunds to shippers. FERC and state regulatory authorities generally have not investigated rates, unless the rates are the subject of a protest or a complaint. Phillips 66 has agreed not to contest our tariff rates applicable for our transportation services agreements for the term of those agreements. However, FERC or a state regulatory authority could investigate our rates on its own initiative or at the urging of a third party, and this could lead to a refund of previously collected revenue.

Pipeline Safety

Our assets are subject to increasingly strict safety laws and regulations. The transportation and storage of crude oil, natural gas liquids and refined petroleum products involves a risk that hazardous liquids may be released into the environment, potentially causing harm to the public or the environment. In turn, any such incidents may result in substantial expenditures for response actions, significant government penalties, liability to government agencies for natural resources damages, and significant business interruption. The United States Department of Transportation (DOT) has adopted safety regulations with respect to the design, construction, operation, maintenance, inspection and management of pipeline assets. These regulations contain requirements for the development and implementation of pipeline integrity management programs, which include the inspection and testing of pipelines and necessary maintenance or repairs. These regulations also require that pipeline operation and maintenance personnel meet certain qualifications and that pipeline operators develop comprehensive spill response plans. We are subject to regulation by the DOT under the Hazardous Liquid Pipeline Safety Act of 1979 (the HLPSA). The HLPSA delegated to DOT the authority to develop, prescribe, and enforce minimum federal safety standards for the transportation of hazardous liquids by pipeline. Congress also enacted the Pipeline Safety Act of 1992 (the PSA), which added the environment to the list of statutory factors that must be considered in establishing safety standards for hazardous liquid pipelines, required regulations be issued to define the term “gathering line” and establish safety standards for certain “regulated gathering lines,” and mandated that regulations be issued to establish criteria for operators to use in identifying and inspecting pipelines located in High Consequence Areas (HCAs), defined as those areas that are unusually sensitive to environmental damage, that cross a navigable waterway, or that have a high population density. In 1996, Congress enacted the Accountable Pipeline Safety and Partnership Act (the APSPA), which limited the operator identification requirement mandate to pipelines that cross a waterway where a substantial likelihood of commercial navigation exists, required that certain areas where a pipeline rupture would likely cause permanent or long-term environmental damage be considered in determining whether an area is unusually sensitive to environmental damage, and mandated that regulations be issued for the qualification and testing of certain pipeline personnel. In the Pipeline Inspection, Protection, Enforcement, and Safety Act of 2006, Congress required mandatory inspections for certain U.S. crude oil and natural gas transmission pipelines in HCAs and mandated that regulations be issued for low-stress hazardous liquid pipelines and pipeline control room management. We are also subject to the Pipeline Safety, Regulatory Certainty and Job Creation Act of 2011, which increased penalties for safety violations, established additional safety requirements for newly constructed pipelines, and required studies of certain safety issues that could result in the adoption of new regulatory requirements for existing pipelines.

DOT’s Pipeline and Hazardous Materials Safety Administration (PHMSA) administers compliance with these statutes and has promulgated comprehensive safety standards and regulations for the transportation of hazardous liquid by pipeline, including regulations for (i) the design and construction of new pipeline systems or those that have been relocated, replaced, or otherwise changed; (ii) pressure testing of new pipelines; (iii) operation and maintenance of pipeline systems, establishing programs for public awareness and damage prevention, and managing the operation of pipeline control rooms; (iv) protection of steel pipelines from the adverse effects of internal and external corrosion; and (v) integrity management requirements for pipelines in HCAs.

We monitor the structural integrity of our pipelines through a program of periodic internal assessments using high resolution internal inspection tools, as well as hydrostatic testing and direct assessment that conforms to regulatory standards. We accompany these assessments with a review of the data and repair anomalies, as required, to ensure the integrity of the pipeline. We then utilize sophisticated risk algorithms and a comprehensive data integration effort to ensure that the highest risk-assessed pipelines receive priority for subsequent integrity assessments. We use external coatings and impressed-current cathodic protection systems to protect against external corrosion. We conduct all cathodic protection work in accordance with National Association of Corrosion Engineers standards. We continually monitor, test and record the effectiveness of these corrosion inhibiting systems.

Product Quality Standards

Refined petroleum products that we transport are generally sold by our customers for use by the public. Various federal, state and local agencies have the authority to prescribe product quality specifications for products. Changes in product quality specifications or blending requirements could reduce our throughput volumes, require us to incur additional handling costs or require capital expenditures. For example, different product specifications for different markets affect the fungibility of the products in our system and could require the construction of additional storage. If we are unable to recover these costs through increased revenue, our cash flows and ability to pay cash distributions could be adversely affected. In addition, changes in the product quality of the products we receive on our product pipeline systems could reduce or eliminate our ability to blend products.

Terminal and Processing Unit Safety

Our operations are subject to regulations promulgated by the U.S. Occupational Safety and Health Administration (OSHA), DOT and comparable state and local regulations. We have identified which assets are subject to the jurisdiction of OSHA or DOT. Certain of our facilities are under the dual jurisdiction of OSHA and DOT, whereby certain portions of the facility are subject to OSHA regulation and other assets at the facility are subject to DOT regulation due to the type of asset and the configuration of the facility. Our facilities are operated in a manner consistent with industry safety practices and standards. The tanks designed for crude oil and refined petroleum product storage at our facilities are equipped with appropriate emission controls to promote safety. Our facilities have response plans, spill prevention and control plans, and other programs to respond to emergencies.

Rail Safety

Our rail operations involve crude oil loading, receiving and unloading activities. Generally, rail operations are subject to regulations promulgated by the U.S. Department of Transportation Federal Railroad Administration, PHMSA and comparable state and local regulations. We believe our rail operations are in material compliance with all applicable regulations and meet or exceed current industry standards and practices.

Security

We are also subject to Department of Homeland Security Chemical Facility Anti-Terrorism Standards, which are designed to regulate the security of high-risk chemical facilities, the Transportation Security Administration’s Pipeline Security Guidelines, and other comparable state and local regulations. We have an internal program of inspection designed to monitor and provide for compliance with all of these requirements. We believe that we are in material compliance with all applicable laws and regulations regarding the security of our facilities. However, these laws and regulations are subject to changes, or to changes in their interpretation, by the regulatory authorities, and continued and future compliance with such laws and regulations may require us to incur significant expenditures.  In addition, any incidents may result in substantial expenditures for response actions, government penalties and business interruption.

While we are not currently subject to governmental standards for the protection of computer-based systems and technology from cyber threats and attacks, proposals to establish such standards are being considered in the U.S. Congress and by U.S. Executive Branch departments and agencies, including the Department of Homeland Security, and we may become subject to such standards in the future. We currently are implementing our own cyber security programs and protocols; however, we cannot guarantee their effectiveness. A significant cyber attack could have a material effect on our operations and those of our customers.

ENVIRONMENTAL REGULATIONS

General

Our operations are subject to extensive and frequently changing federal, state and local laws, regulations and ordinances relating to the protection of the environment. Among other things, these laws and regulations govern the emission or discharge of pollutants into or onto the land, air and water, the handling and disposal of solid and hazardous wastes and the remediation of contamination. As with the industry generally, our compliance with existing and anticipated environmental laws and regulations increases our overall cost of business, including our capital costs to construct, maintain, operate and upgrade equipment and facilities. While these laws and regulations affect our maintenance capital expenditures and net income, we believe they do not affect our competitive position, as the operations of our competitors are largely affected in a similar manner. We believe our facilities are in substantial compliance with applicable environmental laws and regulations. However, these laws and regulations are subject to changes, or to changes in their

interpretation, by regulatory authorities, and continued and future compliance with such laws and regulations may require us to incur significant expenditures. Additionally, violation of environmental laws, regulations, and permits can result in the imposition of significant administrative, civil and criminal penalties, injunctions limiting our operations, investigatory or remedial liabilities or construction bans or delays in the construction of additional facilities or equipment. Further, a release of hydrocarbons or hazardous substances into the environment could, to the extent the event is not insured, subject us to substantial expenses, including costs to comply with applicable laws and regulations and to resolve claims by third parties for personal injury or property damage, or by the U.S. federal government or state governments for natural resources damages. These impacts could directly and indirectly affect our business and have an adverse impact on our financial position, results of operations and liquidity. We cannot currently determine the amounts of such future impacts.

Expensed environmental costs were $4 million in 2018 and are expected to be less than $5 million in 2019 and 2020. The majority of the environmental expenses forecasted for 2019 and 2020 relate to environmental matters attributable to ownership of our assets prior to their acquisition from Phillips 66. Phillips 66 has agreed to retain responsibility for these liabilities. Accordingly, although these amounts would be expensed by us, there would be no required cash outflow from us. See the “Indemnification and Excluded Liabilities” section to follow for additional information on Phillips 66-retained liabilities. Capitalized environmental costs were $8 million in 2018 and are expected to be approximately the same in 2019 and 2020. These amounts do not include capital expenditures made for other purposes that have an indirect benefit on environmental compliance.

Air Emissions and Climate Change

We are subject to the Federal Clean Air Act (FCAA) and its regulations and comparable state and local statutes and regulations in connection with air emissions from our operations. Under these laws, permits may be required before construction can commence on a new source of potentially significant air emissions, and operating permits may be required for sources that are already constructed. These permits may require controls on our air emission sources, and we may become subject to more stringent regulations requiring the installation of additional emission control technologies.

Future expenditures may be required to comply with the FCAA and other federal, state and local requirements for our various sites, including our pipeline and storage facilities. The impact of future legislative and regulatory developments, if enacted or adopted, could result in increased compliance costs and additional operating restrictions on our business, all of which could have an adverse impact on our financial position, results of operations and liquidity.

Air emissions requirements also affect Phillips 66’s domestic refineries from which we directly or indirectly receive the majority of our revenue. Phillips 66 has been required in the past, and will likely be required in the future, to incur significant capital expenditures to comply with new legislative and regulatory requirements relating to its operations. To the extent these capital expenditures have a material effect on Phillips 66, they could have a material effect on our business and results of operations.

In December 2007, Congress passed the Energy Independence and Security Act (EISA) that created a second Renewable Fuels Standard (RFS2). This standard requires the total volume of renewable transportation fuels (including ethanol and advanced biofuels) sold or introduced annually in the United States to rise to 36 billion gallons by 2022. The requirements could reduce future demand for petroleum products and thereby have an indirect effect on certain aspects of our business. For compliance years 2015 through 2019, the U.S. Environmental Protection Agency (EPA) reduced the statutory volumes of advanced and total renewable fuels using authority granted to it under the EISA. The EPA’s actions pertaining to these compliance years have been or, with respect to 2019, may soon be, legally challenged.

Currently, various legislative and regulatory measures to address greenhouse gas (GHG) emissions (including carbon dioxide, methane and other gases) are in various phases of discussion or implementation. These include existing requirements to report emissions of GHGs to the EPA, and proposed federal legislation and regulation as well as state actions to develop statewide or regional programs, each of which require or could require reductions in our GHG emissions or those of Phillips 66. In addition, the United Nations Framework Convention on Climate Change, commonly known as the Paris Agreement, entered into force on November 4, 2016. The Paris Agreement could lead to further GHG emission reduction requirements. Requiring reductions in GHG emissions could result in increased costs to (1) operate and maintain our facilities, (2) install new emission controls at our facilities and (3) administer and manage any GHG emissions programs, including acquiring emission credits or allotments. These requirements may also impact Phillips 66’s domestic refinery operations and may have an indirect effect on our business, financial condition and results of

operations. In 2017, however, the President of the United States announced his intention to withdraw the United States from the Paris Agreement.

In addition, the EPA has proposed and may adopt further regulations under the FCAA addressing GHGs, some of which may directly impact Phillips 66’s domestic refinery operations, while others, such as the EPA’s Clean Power Plan (CO ₂ emission rules for existing fossil fuel-fired electric generating units), which remains the subject of litigation and administrative reconsideration, may indirectly affect such operations. Both types of impacts may affect our business. In October 2017, the EPA commenced rulemaking proceedings to rescind the Clean Power Plan, and in December 2017, the EPA published an Advanced Notice of Proposed Rulemaking, announcing an intent to commence a new rulemaking to replace the Clean Power Plan with an alternative framework for regulating carbon dioxide. In August 2018, the EPA proposed the Affordable Clean Energy (ACE) rule as a replacement for the Clean Power Plan.

Congress continues to consider legislation on GHG emissions, which may include a delay in the implementation of GHG regulations by the EPA or a limitation on the EPA’s authority to regulate GHGs, although the ultimate adoption and form of any federal legislation cannot presently be predicted. The impact of future regulatory and legislative developments, if adopted or enacted, including any cap-and-trade program, is likely to result in increased compliance costs, increased utility costs, additional operating restrictions on our business, and an increase in the cost of products generally. Although such costs may impact our business directly or indirectly by impacting Phillips 66’s facilities or operations, the extent and magnitude of that impact cannot be reliably or accurately estimated due to the present uncertainty regarding the additional measures and how they will be implemented.

Waste Management and Related Liabilities

To some extent, the environmental laws and regulations affecting our operations relate to the release of hazardous substances or solid wastes into soils, groundwater, and surface water, and include measures to control pollution of the environment. These laws generally regulate the generation, storage, treatment, transportation, and disposal of solid and liquid hazardous waste. They also require corrective action, including investigation and remediation, at a facility where such waste may have been released or disposed.

The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), which is also known as Superfund, and comparable state laws impose liability, without regard to fault or to the legality of the original conduct, on certain classes of persons that contributed to the release of a “hazardous substance” into the environment. These persons include the former and present owner or operator of the site where the release occurred and the transporters and generators of the hazardous substances found at the site. Under CERCLA, these persons may be subject to joint and several liabilities for the costs of cleaning up the hazardous substances released into the environment, for damages to natural resources, and for the costs of certain health studies. CERCLA also authorizes the EPA and, in some instances, third parties to act in response to threats to the public health or the environment and to seek to recover from the responsible classes of persons the costs they incur. It is not uncommon for neighboring landowners and other third parties to file claims for personal injury and property damage allegedly caused by hazardous substances or other pollutants released into the environment. In the course of our ordinary operations, we generate waste that falls within CERCLA’s definition of a “hazardous substance,” and, as a result, we may be jointly and severally liable under CERCLA for all or part of the costs required to clean up certain sites where we alleged to have liability.

We also generate solid wastes, including hazardous wastes, that are subject to the requirements of the Resource Conservation and Recovery Act (RCRA) and comparable state statutes. From time to time, the EPA considers the adoption of stricter disposal standards for non-hazardous wastes. Hazardous wastes are subject to more rigorous and costly disposal requirements than are non-hazardous wastes. Any changes in the regulations could increase our maintenance capital expenditures and operating expenses. We continue to seek methods to minimize the generation of hazardous wastes in our operations.

We currently own and lease, and Phillips 66 has in the past owned and leased, properties where hydrocarbons are being handled or for many years have been handled. Although we utilized operating and disposal practices that were standard in the industry at the time, hydrocarbons or other waste may have been disposed of or released on or under the properties owned or leased by us or on or under other locations where these wastes have been transported for disposal. In addition, many of these properties were operated by third parties whose treatment and disposal or release of hydrocarbons or other wastes were not under our control. These properties and wastes disposed thereon may be subject to CERCLA, RCRA and analogous state laws. Under these laws, we could be required to remove or remediate previously disposed wastes

(including wastes disposed of or released by prior owners or operators), to clean up contaminated property (including contaminated groundwater), or to perform remedial operations to prevent further contamination.

Water

Our operations can result in the discharge of pollutants, including crude oil and petroleum products. Regulations under the Water Pollution Control Act of 1972 (Clean Water Act), Oil Pollution Act of 1990 (OPA 90) and comparable state laws impose regulatory burdens on our operations. Spill Prevention Control and Countermeasure (SPCC) requirements of federal laws and some state laws require containment to prevent or mitigate contamination of navigable waters in the event of an oil overflow, rupture, or leak. For example, the Clean Water Act requires us to maintain SPCC plans at many of our facilities. We maintain numerous discharge permits as required under the National Pollutant Discharge Elimination System program of the Clean Water Act and have implemented systems to oversee our compliance efforts.

In addition, the transportation and storage of crude oil and petroleum products over and adjacent to water involves risk and subjects us to the provisions of OPA 90 and related state requirements. Among other requirements, OPA 90 requires the owner or operator of a vessel or a facility to maintain an emergency plan to respond to releases of oil or hazardous substances. Also, in case of any such release, OPA 90 requires the responsible entity to pay resulting removal costs and damages. OPA 90 also provides for civil penalties and imposes criminal sanctions for violations of its provisions. We operate facilities at which releases of oil and hazardous substances could occur. We have implemented emergency spill response plans for all of our components and facilities covered by OPA 90, and we have established SPCC plans for facilities subject to Clean Water Act SPCC requirements. Construction or maintenance of our pipelines, terminals and storage facilities may impact wetlands, which are also regulated under the Clean Water Act by the EPA and the United States Army Corps of Engineers. Regulatory requirements governing wetlands (including associated mitigation projects) may result in the delay of our projects while we obtain necessary permits and may increase the cost of new projects and maintenance activities.

Workplace Safety

We are subject to requirements promulgated by OSHA and comparable state statutes that regulate the protection of the health and safety of workers. In addition, the OSHA hazard communication standard requires that information be maintained about hazardous materials used or produced in our operations and that this information be provided to employees, state and local government authorities and citizens. We believe our operations are in substantial compliance with OSHA requirements, including general industry standards, record keeping requirements, and monitoring of occupational exposure to regulated substances.

Endangered Species Act

The Endangered Species Act and its state law equivalents restrict activities that may affect endangered species or their habitats. While some of our facilities are in areas that may be designated as habitats for endangered species, we believe we are in substantial compliance with the Endangered Species Act. However, the discovery of previously unidentified endangered species could cause us to incur additional costs or become subject to operating restrictions or bans in the affected area.

Hazardous Materials Transportation Requirements

The DOT regulations affecting pipeline safety require pipeline operators to implement measures designed to reduce the environmental impact of crude oil and petroleum products discharge from onshore crude oil and petroleum product pipelines. These regulations require operators to maintain comprehensive spill response plans, including extensive spill response training for pipeline personnel. In addition, the DOT regulations contain detailed specifications for pipeline operation and maintenance. We believe our operations are in substantial compliance with these regulations. The DOT also has a pipeline integrity management rule, with which we are in substantial compliance.

Indemnification and Excluded Liabilities

Under our amended omnibus agreement and pursuant to the terms of various agreements under which we acquired assets from Phillips 66, Phillips 66 will indemnify us, or assume responsibility, for certain environmental liabilities, tax liabilities, litigation and any other liabilities attributable to the ownership or operation of the assets contributed to us and that arose prior to the effective date of each acquisition. These indemnifications and exclusions from liability have, in some cases, time limits and deductibles. When Phillips 66 performs under any of these indemnifications or exclusions from liability, we recognize non-cash expenses and associated non-cash capital contributions from our General Partner, as these are considered liabilities paid for by a principal unitholder.

GENERAL

Major Customer

Phillips 66 accounted for 96 percent , 95 percent , and 95 percent of our total operating revenues in the years ended December 31, 2018 , 2017 and 2016 , respectively. Through our wholly owned and joint venture operations, we provide crude oil, refined petroleum products and NGL pipeline transportation, terminaling and storage, and crude oil gathering, NGL fractionation, crude oil processing, and rail-unloading services to Phillips 66.

Seasonality

The volumes of crude oil, refined petroleum products and NGL transported in our wholly owned and joint venture pipelines, stored in our terminals, rail racks and storage facilities and processed through our fractionator and processing units are directly affected by the level of supply and demand for crude oil, refined petroleum products and NGL in the markets served directly or indirectly by our assets. The effects of seasonality on our cash flows should be substantially mitigated through the use of fee-based commercial agreements that include minimum volume commitments.

Pipeline Control Operations

Our wholly owned pipeline systems are operated from a central control room owned and operated by Phillips 66. The control center operates with a supervisory control and data acquisition system equipped with computer systems designed to continuously monitor operational data. Monitored data includes pressures, temperatures, gravities, flow rates and alarm conditions. The control center operates remote pumps, motors and valves associated with the receipt and delivery of crude oil and refined petroleum products, and provides for the remote-controlled shutdown of pump stations on the pipeline systems. A fully functional back-up operations center is also maintained and routinely operated throughout the year to ensure safe and reliable operations.

Employees

We are managed and operated by the executive officers of our General Partner with oversight provided by its Board of Directors. Neither we nor our subsidiaries have any employees. Our General Partner has the sole responsibility for providing the employees and other personnel necessary to conduct our operations. As of December 31, 2018 , Phillips 66 employed approximately 600 people who provided direct support for our operations.

Website Access to SEC Reports

Our Internet website address is http://www.phillips66partners.com . Information contained on our Internet website is not part of this Annual Report on Form 10-K.

Our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, as well as any amendments and exhibits to these reports, filed or furnished pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended, are available on our website, free of charge, as soon as reasonably practicable after such reports are filed with, or furnished to, the Securities and Exchange Commission (the SEC). Alternatively, you may access these reports at the SEC’s website at http://www.sec.gov . We also post on our website our beneficial ownership reports filed by officers and directors of our General Partner, as well as principal security holders, under Section 16(a) of the Securities Exchange Act of 1934, governance guidelines, audit and conflicts committee charters, code of business ethics and conduct, and information on how to contact our General Partner’s Board of Directors.