U.S. Environmental Emissions and Pollution Control System

A key permitting system under the U.S. Clean Air Act (CAA) for major facilities and large emission sources. It consists of two layers: New Source Review (NSR — including Prevention of Significant Deterioration (PSD) and Nonattainment Area NSR), which applies to new construction and major modifications, and the operating permit program (Title V), which applies to all major sources. While built on the federal EPA's National Ambient Air Quality Standards (NAAQS) and Hazardous Air Pollutant (HAP) standards (MACT), state governments (e.g., California's CARB, Texas's TCEQ) often impose their own stricter add-on requirements and permitting procedures, forcing operators to navigate an extremely complex, overlapping compliance burden at both the federal and state levels.

Under the U.S. Clean Water Act (CWA), facilities that discharge industrial wastewater directly into public waters, or indirectly into a Publicly Owned Treatment Works (POTW), are subject to the National Pollutant Discharge Elimination System (NPDES) and Pretreatment standards.

The "Justice40 Initiative" (a policy directing 40% of federal environmental investment benefits to disadvantaged communities), along with the EJScreen (Environmental Justice screening tool) and CEJST (Climate and Economic Justice Screening Tool), had been central pillars of environmental justice (EJ) policy promoted during the Biden administration. Following President Trump's inauguration on January 20, 2025, these programs were fully suspended and rescinded at the federal level through the revocation of Executive Order 14057 and related orders. Funding for the EPA's Office of Environmental Justice and External Civil Rights was cut off, and data updates to the screening tools have ceased. However, in states with their own environmental justice statutes—such as California and New York, which restrict new permitting in cumulatively burdened communities—state-level regulation and litigation continue. As a result, the regulatory landscape is diverging between the federal and state levels.

The National Primary Drinking Water Regulation (NPDWR) finalized by the U.S. Environmental Protection Agency (EPA) in April 2024 under the Safe Drinking Water Act (SDWA) set nationwide, legally enforceable Maximum Contaminant Levels (MCLs) for specific PFAS in drinking water: PFOA, PFOS, PFHxS, PFNA, HFPO-DA (GenX), and certain mixtures. The MCLs for PFOA and PFOS are 4.0 parts per trillion (ppt) each. In May 2026, however, EPA proposed a rule that would keep the PFOA and PFOS MCLs while allowing water systems that apply to extend their compliance deadline from 2029 to 2031, and a separate rule that would rescind the regulations for PFHxS, PFNA, HFPO-DA, and Hazard Index mixtures. Public comment on both proposals closed on July 20, 2026. As of September 27, 2026, neither has been finalized, and the current rule remains legally in effect.

A final rule under which EPA designated PFOA and PFOS as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA / Superfund Law). It imposes a release reporting obligation above a threshold quantity (1 pound per 24 hours) and strict, joint-and-several, retroactive liability for past and present land and groundwater contamination, regardless of fault.

The U.S. Clean Air Act (CAA) is a comprehensive regulatory framework administered by EPA to maintain and achieve the National Ambient Air Quality Standards (NAAQS). Through the operating permit program (Title V) for major sources and New Source Performance Standards (NSPS), it strictly limits hazardous air pollutant (HAP) emissions from factories and facilities. Companies are required to manage emission allowances (such as cap-and-trade systems) and conduct continuous emissions monitoring and reporting; violations carry the risk of substantial fines or business suspension, requiring a sophisticated compliance framework across the supply chain.

The Greenhouse Gas Reporting Program (GHGRP), administered by the U.S. Environmental Protection Agency (EPA), has collected emissions data from major sources since the program's establishment in 2009. On September 9, 2025, however, EPA published a proposed rule under the Clean Air Act that would rescind or reduce reporting requirements for the large majority of covered sectors. Notably, the proposal would delay the reporting requirement for methane emissions from the oil and gas sector (Subpart W) until 2034. This policy shift is expected to have ripple effects on other programs that rely on GHGRP data, including Clean Air Act performance standard assessments, fee calculations for methane emission reduction programs, and carbon capture tax credit calculations under the Inflation Reduction Act. Within the oil and gas industry itself, views are mixed: some welcome the reduced reporting burden, while others call for maintaining the reliability of the underlying database.

The American Innovation and Manufacturing (AIM) Act is a federal law under which EPA phases down the production and consumption of hydrofluorocarbons (HFCs), potent greenhouse gases. Enacted in 2020 and aligned with the Kigali Amendment to the Montreal Protocol, it aims to reduce HFC consumption by 85% from baseline by 2036. It covers a wide range of applications including refrigerants, foam-blowing agents, and solvents, and strongly encourages a supply-chain-wide transition to alternative substances along with the promotion of recovery and reclamation.

This federal emissions standard, finalized by the U.S. Environmental Protection Agency (EPA) in March 2024, covers passenger cars, light-duty trucks (SUVs, pickups, etc.), and medium-duty vehicles for model years 2027 through 2032. It originally required phased, substantial reductions in both greenhouse gas emissions (CO2, etc.) and criteria air pollutants (NMOG+NOx, PM, etc.). In February 2026, however, EPA under the Trump administration finalized a rule rescinding the 2009 Greenhouse Gas Endangerment Finding, which had served as the legal basis for the rule's GHG emissions standards—raising significant doubt as to the continued effect of the GHG provisions. Separately, on May 18, 2026, EPA published a proposed rule to delay the effective date of the Tier 4 criteria pollutant standards from model year 2027 to model year 2029.