Western Midstream Partners LP

Our business operations are subject to numerous federal, regional, state, tribal, and local environmental and occupational health and safety laws and regulations. The more significant of these existing environmental laws and regulations include the following legal standards that exist currently in the United States, as amended from time to time:

•the Clean Air Act, which restricts the emission of air pollutants from many sources and imposes various pre-construction, operational, monitoring, and reporting requirements for new, reconstructed, modified, and existing sources, and that the U.S. Environmental Protection Agency (the “EPA”) has relied on as the authority for adopting climate-change regulatory initiatives relating to greenhouse gas (“GHG”) emissions;

•the Federal Water Pollution Control Act, also known as the Clean Water Act, which regulates discharges of pollutants from facilities to state and federal waters and establishes the extent to which waterways are subject to federal jurisdiction and rulemaking as protected waters of the United States;

•the Oil Pollution Act of 1990, which subjects, among others, owners and operators of onshore facilities and pipelines to liability for removal costs and damages arising from an oil spill in waters of the United States;

•regulations imposed by the Bureau of Land Management (the “BLM”) and the Bureau of Indian Affairs, agencies under the authority of the U.S. Department of the Interior, which govern and restrict aspects of oil and natural-gas operations on federal and Native American lands, including the imposition of liabilities for pollution damages and pollution clean-up costs resulting from such operations;

•regulations imposed by the U.S. Army Corps of Engineers (“Corps”) that govern and restrict activities that may affect federally regulated waters and wetlands;

•the Comprehensive Environmental Response, Compensation and Liability Act of 1980, which imposes liability on generators, transporters, and arrangers of hazardous substances at sites where hazardous substance releases have occurred or are threatening to occur;

•the Resource Conservation and Recovery Act, which governs the generation, treatment, storage, transport, and disposal of solid wastes, including hazardous wastes;

•the Safe Drinking Water Act, which regulates the quality of the nation’s public drinking water through adoption of drinking-water standards and control over the injection of waste fluids into non-producing geologic formations that may adversely affect drinking water sources;

•the Emergency Planning and Community Right-to-Know Act, which requires facilities to implement a safety-hazard communication program and disseminate information to employees, local emergency planning committees, and response departments on toxic chemical uses and inventories;

•the Occupational Safety and Health Act, which establishes workplace standards for the protection of the health and safety of employees, including the implementation of hazard communications programs designed to inform employees about hazardous substances in the workplace, potentially harmful effects of these substances, and appropriate control measures;

•the Endangered Species Act (“ESA”), which restricts activities that may affect federally identified endangered and threatened species or their habitats through the implementation of operating restrictions or a temporary, seasonal, or permanent ban in affected areas, and similar protections for migratory birds under the Migratory Bird Treaty Act (“MBTA”);

•the National Environmental Policy Act, which requires federal agencies to evaluate major agency actions having the potential to impact the environment and that may require the preparation of environmental assessments and more detailed environmental impact statements that may be made available for public review and comment; and

•U.S. Department of Transportation regulations, which relate to advancing the safe transportation of hazardous materials, pipeline safety, and emergency response preparedness.

Additionally, regional, state, tribal, and local jurisdictions exist in the United States where we operate that also have, or are developing or considering developing, similar environmental laws and regulations governing many of these same types of activities. While the legal requirements imposed under state law may be similar in form to federal laws and regulations, in some cases, the actual implementation of these requirements may impose additional, or more stringent, conditions or controls that can significantly alter or delay the permitting, development, or expansion of a project or substantially increase the cost of doing business. These federal and state environmental laws and regulations, including new or amended legal requirements that may arise in the future to address potential environmental concerns such as air and water impacts and oil and natural-gas development in close proximity to specific occupied structures and/or certain environmentally sensitive or recreational areas, are expected to continue to have a considerable impact on our operations.

In connection with our operations, we have acquired certain properties supportive of oil and natural-gas activities from third parties whose actions with respect to the management and disposal or release of hydrocarbons, hazardous substances, or wastes were not under our control. Under environmental laws and regulations, we could incur strict joint and several liability for remediating hydrocarbons, hazardous substances, or wastes disposed of or released by prior owners or operators. We also could incur costs related to the clean-up of third-party sites to which we sent regulated substances for disposal or recycling, and for damages to natural resources or other claims related to releases of regulated substances at or from such third-party sites.

These federal and state laws and their implementing regulations generally restrict the level of pollutants emitted to ambient air, discharges to surface water, and disposals, or other releases, to surface and below-ground soils and ground water. Failure to comply with these laws and regulations may result in the assessment of sanctions, including administrative, civil, and criminal penalties; the imposition of investigatory, remedial, and corrective-action obligations or the incurrence of capital expenditures; the occurrence of delays or cancellations in the permitting, development, or expansion of projects; and the issuance of injunctions restricting or prohibiting some or all of our activities in a particular area. Moreover, there exist environmental laws that provide for citizen suits, which allow individuals and environmental organizations to act in the place of the government and sue operators for alleged violations of environmental law. See the following Risk Factors under Part I, Item 1A of this Form 10-K for further discussion on environmental matters such as ozone standards, climate change, including methane or other GHG emissions, hydraulic fracturing, and other regulatory initiatives related to environmental protection:“We are subject to stringent and comprehensive environmental laws and regulations that may expose us to significant costs and liabilities,” “Adoption of new or more stringent climate-change or other air-emissions legislation or regulations restricting emissions of GHGs or other air pollutants could negatively impact us, our producer customers, or downstream customers by increasing operating costs and reducing volumetric throughput on our systems due to reduced demand for the gathering, processing, compressing, treating, and transporting services we provide,” “Changes in laws or regulations regarding hydraulic fracturing could result in increased costs, operating restrictions, or delays in the completion of oil and natural-gas wells, which could decrease the need for our gathering and processing services,”and“Physical injection constraints and the adoption of new or more stringent legal standards relating to induced seismic activity could affect our produced-water disposal operations.” The ultimate financial impact arising from environmental laws and regulations is neither clearly known nor determinable, as existing standards are subject to change and new standards continue to evolve.

We have incurred and will continue to incur operating and capital expenditures, some of which may be material, to comply with environmental and occupational health and safety laws and regulations. Historically, our environmental compliance costs have not had a material adverse effect on our results of operations; however, there can be no assurance that such costs will not have a material adverse effect on our business, financial condition, results of operations, or cash flows in the future, or that new or more stringently applied existing laws and regulations will not materially increase our costs of doing business. Although we are not fully insured against all environmental risks, and our insurance does not cover any penalties or fines that may be issued by a governmental authority, we maintain insurance coverage that we believe sufficient based on our assessment of insurable risks and consistent with insurance coverage held by other similarly situated industry participants. Nevertheless, it is possible that other developments, such as stricter and more comprehensive environmental laws and regulations, and claims for damages to property or persons or imposition of penalties resulting from our operations, could have a material adverse effect on our results of operations.

The following are examples of proposed and/or final regulations or other regulatory initiatives that could have a potentially material impact on us:

•Ground-Level Ozone Standards. In 2015, the EPA issued a rule under the Clean Air Act, lowering the National Ambient Air Quality Standard (“NAAQS”) for ground-level ozone from 75 parts per billion under the primary standard to 70 parts per billion under the secondary standard to provide requisite protection of public health and welfare. In 2017 and 2018, the EPA issued area designations with respect to ground-level ozone as either “attainment/unclassifiable,” “unclassifiable,” or “non-attainment.” Additionally, in November 2018, the EPA issued final requirements that apply to state, local, and tribal air agencies for implementing the 2015 NAAQS for ground-level ozone. By law, the EPA must review each NAAQS every five years. In December 2020, the EPA announced that it was retaining without revision the 2015 NAAQS for ozone. Subsequently, in January 2021, the Biden Administration announced that it will reconsider the December 2020 final action in favor of a more stringent ground-level ozone standard. Ongoing state implementation of the 2015 NAAQS, as well as potential implementation of even more stringent ground-level ozone standards, could, among other things, require installation of new emission controls on some of our or our customer’s equipment, result in longer permitting timelines, and significantly increase our capital expenditures and operating costs.

•Standards Requiring Reduction of Methane and Other Emissions by the Oil and Gas Industry. In March 2024, the EPA published New Source Performance Standards (“NSPS”) and Emissions Guidelines (“EGs”), known as Subpart OOOOb and Subpart OOOOc, respectively, which introduce emissions standards for methane and volatile organic compounds (“VOCs”) from certain new, modified, and reconstructed oil and natural-gas production, processing and transmission facilities. Subpart OOOOc will additionally apply new standards to existing facilities. These rules set more stringent standards and requirements for a variety of sources including flares, wells, storage vessels, compressors, pumps, sweetening units, equipment that may leak, and others. Among the many additional requirements, one notable addition is the creation of a Super Emitter Program that, among other things, authorizes the EPA to require the operator to respond when third parties detect and notify the EPA of remotely-detected emissions. Subpart OOOOb generally became effective in May 2024, with rolling compliance dates for certain sources. Subpart OOOOc, which will apply to existing sources, has a longer implementation timeline, requiring each state to submit a plan to the EPA for appropriate emissions reductions within two years of the date that the rule is published, and regulated entities will be required to comply with state or federal rules within three years after the deadline for state plan submittals. Although any state-implemented rules must be at least as stringent as the federal rules, we cannot predict the full scope of any final regulatory requirements imposed by the states or the cost to comply with such requirements. Also, at the state level, some states where we conduct operations, including Colorado, have implemented requirements for the performance of leak detection programs that require identification and repair of methane leaks at certain oil and natural-gas sources. States are also imposing rules to limit other emissions from oil and gas operations.

For example, in 2024, Colorado’s Governor Polis signed Senate Bill 24-229 seeking to reduce ozone emissions by requiring the Colorado Department of Public Health and Environment (“CDPHE”) to propose rules to reduce oil and gas NOx emissions by 50% by 2030, relative to 2017 levels. Compliance with these rules or with any similar or future federal or state regulation of methane or other emissions from operations could, among other things, require installation of new emission controls on some of our equipment and increase our capital expenditures and operating costs, and could have a material adverse effect on our business, financial condition, and results of operations.

•Reduction of GHG Emissions. The U.S. Congress and the EPA, in addition to some state and regional authorities, have in recent years considered legislation or regulations to reduce GHG emissions. These efforts have included consideration of cap-and-trade programs, carbon taxes, methane fees, GHG-reporting and tracking programs, and regulations that directly limit GHG emissions from certain sources. The EPA has determined that GHG emissions present a danger to public health and the environment and has adopted regulations that, among other things, restrict GHG emissions under existing Clean Air Act provisions and may require the installation of “best available control technology” to limit GHG emissions from any new or significantly modified facilities that we may seek to construct in the future if they would otherwise emit large volumes of GHGs together with other criteria pollutants. Also, certain of our operations are subject to EPA rules requiring the monitoring and annual reporting of GHG emissions from specified onshore and offshore production, processing, and gathering and boosting sources. Additionally, in April 2016, the United States joined other countries in entering into a United Nations-sponsored non-binding agreement negotiated in Paris, France (“Paris Agreement”) for nations to limit their GHG emissions through individually determined reduction goals every five years beginning in 2020, which became effective in November 2016, and since this time, the United States has twice formally joined the Paris Agreement. In response to Paris Agreement commitments, the United States has established an economy-wide target of reducing its net GHG emissions by 50% - 52% below 2005 levels by 2030 and achieving net zero GHG-emissions economy-wide by no later than 2050. In 2022, Congress enacted the Inflation Reduction Act (the “IRA”), which added Section 136 to the Clean Air Act and imposed the first-ever direct federal “charge” on methane emissions called the “Waste Emissions Charge” for applicable facilities within nine segments of the oil and natural gas industry. The IRA states that it will apply to methane emissions beginning in 2024, with the first charge for 2024 emissions due in 2025 along with OOOOb/c requirements. Multiple Congressional efforts, including a direct statutory repeal and a Congressional Review Act resolution pausing implementation, have been filed in 2025 with public statements made by the Trump Administration and Congressional leaders intent on repealing it prior to any charges coming due. The Trump administration has also recently indicated its intention to withdraw from the Paris Agreement. Notwithstanding any formal withdrawal from this agreement, the implementation of substantial limitations on GHG emissions in areas where WES conducts operations could adversely affect demand for oil and gas.

At the state level, the Colorado Air Quality Control Commission (“AQCC”) adopted a similar rule in February 2024, imposing fees on certain operations for greenhouse gas emissions. Colorado also promulgated, or is expected to promulgate, several rules to implement 2021 state legislation requiring the development of air quality regulations that will result in a 20.5% reduction in combustion greenhouse gas emissions from the midstream sector by 2030 as compared to a 2015 baseline. Pursuant to that legislation, in December 2024, the AQCC recommended the adoption of a rule that will require every existing Colorado midstream operator to comply with a 2030 emissions cap on their Colorado operations applicable to GHG emissions from fuel-burning equipment, including engines and heaters. Compliance with emissions caps may be accomplished with the utilization of credits, which may be produced by operators that emit at rates that are lower than their respective caps. Producer credits can be marketed in, or procured from, a credit market in which midstream operators and an assortment of commercial and industrial facilities may participate. Colorado previously adopted regulations for methane emissions from certain oil and natural-gas operations, and imposed certain GHG intensity standards. Generally, GHG intensity standards set numerical limits of carbon dioxide equivalent (CO 2 e) emissions per barrel of oil produced. Subsequently, in July 2023, the AQCC adopted a new rule, which among other things, defines how certain oil and gas facilities must calculate their greenhouse gas intensity, monitor operations to ensure compliance with intensity standards, and keep records to accurately account for emissions from their operations. The implementation of substantial limitations on and/or costs associated with GHG emissions, in areas where we conduct operations could result in increased compliance costs, including to acquire emissions allowances or comply with new regulatory or reporting requirements, which developments could adversely affect demand for oil and natural gas that our customers produce, reduce demand for our services, and could have a material adverse effect on our business, financial condition, and results of operations.

We also dispose of produced water generated from oil and natural-gas production operations. The legal standards related to the disposal of produced water into producing or non-producing geologic formations by means of underground injection wells are subject to change based on concerns of the public or governmental authorities, including concerns relating to seismic events near injection wells used for the disposal of produced water. In response to such concerns, regulators in some states have imposed, or are considering imposing, additional requirements in the permitting of produced-water disposal wells or are otherwise investigating the existence of a relationship between seismicity and the use of such wells. For example, Colorado has issued regulations governing the issuance of underground injection-control permits that limit the maximum injection pressure, rate, and volume of water. Similarly, the Texas Railroad Commission has adopted rules for wastewater disposal wells that impose certain permitting and operating restrictions and reporting requirements on disposal wells in proximity to faults and seismic activity and has also issued directives requiring certain wells to restrict or suspend disposal-well operations near where faults exist or where seismic events have occurred. Another consequence of seismic events near produced-water disposal wells is the introduction of class action lawsuits, which allege that disposal well operations have caused damage to neighboring properties or otherwise violated state and federal rules regulating waste disposal. One or more of these developments could result in additional regulation and restrictions on our use of injection wells to dispose of produced water, which could have a material adverse effect on our results of operations, capital expenditures and operating costs, and financial condition.