Among the flurry of executive orders that President Trump issued in the hours following his inauguration on January 20^th was a memorandum titled Regulatory Freeze Pending Review (2025 Trump Regulatory Freeze Memorandum), which directs agencies to:

1. Refrain from proposing or issuing any rule^[1] in any manner until a President Trump-appointed agency head reviews and approves the rule;
2. Immediately withdraw any rules that have been sent to the Office of Federal Register (OFR) but not published in the Federal Register so that they can be reviewed and approved by a President Trump-appointed agency head; and
3. Consider^[2] postponing for 60 days the effective date for any rules that have been published or issued but have not taken effect, for the purpose of reviewing any questions of fact, law, and policy that the rules may raise.

This memorandum closely mirrors regulatory freeze memoranda issued by the first Trump administration in 2017 (2017 Trump Regulatory Freeze Memorandum) and the Biden administration in 2021, but the immediate impact of the memorandum will likely be different from what we have seen in the past. Six days after the Trump administration issued the 2017 Trump Regulatory Freeze Memorandum, EPA published in the Federal Register a final rule delaying the effective date of 30 final EPA regulations that the agency had published between October 28, 2016 and January 17, 2017. 82 Fed. Reg. 8499 (Jan. 26, 2017). These rules had original effective dates after January 20, 2017, the date that President Trump issued the 2017 Trump Regulatory Freeze Memorandum. Several agencies in the Biden administration, however, including EPA, appear to have been prepared for a regulatory freeze memorandum and avoided issuing final regulations at the end of 2024 that would go into effect after President Trump’s inauguration. For example, EPA’s rule implementing the requirements of the Waste Emissions Charge in the Clean Air Act’s Methane Emissions Reduction Program, enacted as part of the Inflation Reduction Act, went into effect on January 17, 2025. 89 Fed. Reg. 91094 (Nov. 18, 2024).

Nonetheless, some environmental and energy-related regulations may be affected by the freeze. For example, on January 21^st, EPA’s final rule regarding Revisions to the Air Emission Reporting Requirements and proposed rule regarding Clean Water Act Effluent Limitations Guidelines and Standards for PFAS Manufacturers Under the Organic Chemicals, Plastics and Synthetic Fibers Point Source Category were both identified on the White House’s Office of Management and Budget’s (OMB) website as under review, but as of January 22^nd are no longer identified as under OMB review and do not appear on OFR’s website. EPA may have withdrawn these rules from OMB’s consideration in accordance with the 2025 Trump Regulatory Freeze Memorandum, but their status remains unclear.

In addition, the Pipeline and Hazardous Materials Safety Administration (PHMSA) made available on its website pre-publication versions of proposed and final rules that have been submitted to the OFR but are not yet available for public inspection or published in the Federal Register. See Proposed Rule: Safety of Carbon Dioxide and Hazardous Liquid Pipelines; Final Rule: Gas Pipeline Leak Detection and Repair.  These proposed and final rules are subject to the regulatory freeze in accordance with the memorandum’s directive that agencies “[i]mmediately withdraw any rules that have been sent to the [OFR] but not published in the Federal Register” so that they can be reviewed and approved by a President Trump-appointed agency head. Both of these rules appear to have been withdrawn from publication in the Federal Register.  However, we also note that EPA published a proposed rule on January 22^nd that was seemingly subject to the freeze. See National Emission Standards for Hazardous Air Pollutants: Chemical Manufacturing Area Sources Technology Review, 90 Fed. Reg. 7942 (Jan. 22, 2025). In sum, there appears to be some open questions on the status of certain rules not yet published in the Federal Register.

Lastly, final environmental regulations that have been published in the Federal Register as final but that have not yet gone into effect include the following EPA final rules:

1. Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen, Oxides of Sulfur, and Particulate Matter, 89 Fed. Reg. 105692 (Dec. 27, 2024) (eff. Jan. 27, 2025);
2. Integrating e-Manifest With Hazardous Waste Exports and Other Manifest-Related Reports, PCB Manifest Amendments, and Technical Corrections, 89 Fed. Reg. 60692 (Sept. 26, 2024) (eff. Jan. 22, 2025); and
3. Hazardous Waste Generator Improvements Rule, the Hazardous Waste Pharmaceuticals Rule, and the Definition of Solid Waste Rule; Technical Corrections, 89 Fed. Reg. 99727 (Dec. 11, 2024) (eff. Feb. 10, 2025).

Per the 2025 Trump Regulatory Freeze Memorandum, EPA is to consider postponing for 60 days the effective date of these rules for the purpose of reviewing any questions of fact, law, and policy that the rules may raise.

How quickly agencies will be able to initiate review and approval of these regulations depends on the Trump administration’s immediate priorities and how quickly agency roles are filled with President Trump appointees.

^[1] The 2025 Trump Regulatory Freeze Memorandum defines “rule” to include both final rules and “any substantive action by an agency (normally published in the Federal Register) that promulgates or is expected to lead to the promulgation of a final rule or regulation, including notices of inquiry, advance notices of proposed rulemaking, and notices of proposed rulemaking.”

^[2] The use of the word “consider” is one notable difference between the 2017 and 2025 memoranda issued by the Trump administration. The postponement directive in the 2017 Trump Regulatory Freeze Memorandum was not optional.