98
completed
14
in progress
112
total rollbacks

Over four years, the Trump administration dismantled major climate policies and rolled back many more rules governing clean air, water, wildlife and toxic chemicals.

In all, a New York Times analysis, based on research from Harvard Law School, Columbia Law School and other sources, counts nearly 100 environmental rules officially reversed, revoked or otherwise rolled back under Mr. Trump. More than a dozen other potential rollbacks remained in progress by the end but were not finalized by the end of the administration’s term.

“This is a very aggressive attempt to rewrite our laws and reinterpret the meaning of environmental protections,” said Hana V. Vizcarra, a staff attorney at Harvard’s Environmental and Energy Law Program who has tracked the policy changes since 2018. “This administration is leaving a truly unprecedented legacy.”

Rule reversals

Completed
In progress
Total
Air pollution and emissions
28 overturned
2 in progress
30 total
Drilling and extraction
12 overturned
7 in progress
19 total
Infrastructure and planning
14 overturned
0 in progress
14 total
Animals
15 overturned
1 in progress
16 total
Water pollution
8 overturned
1 in progress
9 total
Toxic substances and safety
9 overturned
1 in progress
10 total
Other
12 overturned
2 in progress
14 total
All
98 overturned
14 in progress
112 total

The bulk of the rollbacks identified by the Times were carried out by the Environmental Protection Agency, which weakened Obama-era limits on planet-warming carbon dioxide emissions from power plants and from cars and trucks; removed protections from more than half the nation’s wetlands; and withdrew the legal justification for restricting mercury emissions from power plants.

At the same time, the Interior Department worked to open up more land for oil and gas leasing by limiting wildlife protections and weakening environmental requirements for projects. The Department of Energy loosened efficiency standards for a wide range of products.

In justifying many of the rollbacks, the agencies said that previous administrations had overstepped their legal authority, imposing unnecessary and burdensome regulations that hurt business.

“We have fulfilled President Trump’s promises to provide certainty for states, tribes, and local governments,” a spokeswoman for the E.P.A. said in a statement to The Times, adding that it was “delivering on President Trump’s commitment to return the agency to its core mission: Providing cleaner air, water and land to the American people.”

But environmental groups and legal analysts said the rollbacks have not served that mission.

All told, the Trump administration’s deregulatory actions were estimated to significantly increase greenhouse gas emissions over the next decade and lead to thousands of extra deaths from poor air quality each year.

Many of the rollbacks have been challenged in court by states, environmental groups and others, and some have already been struck down. In the final days of Mr. Trump’s term, a federal appeals court overturned a plan to relax Obama-era restrictions on carbon dioxide emissions from coal- and natural gas-burning power plants, arguing that the agency misinterpreted its obligation under the Clean Air Act to reduce carbon pollution.

The Times identified nearly a dozen more rules that were initially reversed or suspended by the Trump administration but later reinstated, often following lawsuits and other challenges. They are summarized at the bottom of this page, and are not counted in our overall tally.

President-elect Biden is expected to undo several of the rollbacks through executive orders soon after assuming office on Jan. 20, including cancelling the permit for the controversial Keystone XL pipeline and rejoining the Paris climate change agreement. The Democrat-controlled House and Senate could help nullify several more Trump-era rules through a once-obscure law that grants Congress the power to review regulations recently adopted by federal agencies. But other rules will be more difficult to change, requiring months — or even years — of work to repeal and replace.

Below, we have summarized each rule that was targeted for reversal.

Are there rollbacks we missed? Email climateteam@nytimes.com or tweet @nytclimate.

Air pollution and emissions

Completed

1. Weakened Obama-era fuel economy and greenhouse gas standards for passenger cars and light trucks.
E.P.A. and Transportation Department | Read more »
2. Revoked California’s ability to set stricter tailpipe emissions standards than the federal government.
E.P.A. | Read more »
3. Withdrew the legal justification for an Obama-era rule that limited mercury emissions from coal power plants.
E.P.A. | Read more »
4. Formally withdrew the United States from the Paris climate agreement, an international plan to avert catastrophic climate change adopted by nearly 200 counties.
Executive Order | Read more »
5. Changed the way cost-benefit analyses are conducted under the Clean Air Act, potentially making it harder to issue new public health and climate protections.
E.P.A. | Read more »
6. Canceled a requirement for oil and gas companies to report methane emissions.
E.P.A. | Read more »
7. Revised and partially repealed an Obama-era rule limiting methane emissions on public lands, including intentional venting and flaring from drilling operations. A federal court struck down the revision in July 2020, calling the Trump administration’s reasoning “wholly inadequate” and mandating enforcement of the original rule. However, the Obama-era rule was later partially struck down in a separate court case, during which the Trump administration declined to defend it.
Interior Department | Read more »
8. Eliminated Obama-era methane emissions standards for oil and gas facilities and narrowed standards limiting the release of other polluting chemicals known as “volatile organic compounds” to only certain facilities.
E.P.A. | Read more »
9. Withdrew a Clinton-era rule designed to limit toxic emissions from major industrial polluters, and later proposed codifying the looser standards.
E.P.A. | Read more »
10. Revised a program designed to safeguard communities from increases in pollution from new power plants to make it easier for facilities to avoid emissions regulations.
E.P.A. | Read more »
11. Amended rules that govern how refineries monitor pollution in surrounding communities.
E.P.A. | Read more »
12. Overturned Obama-era guidance meant to reduce emissions during power plant start-ups, shutdowns and malfunctions. As part of the process, the E.P.A. also reversed a requirement that Texas follow emissions rules during certain malfunction events.
E.P.A. | Read more »
13. Weakened an Obama-era rule meant to reduce air pollution in national parks and wilderness areas.
E.P.A. | Read more »
14. Weakened oversight of some state plans for reducing air pollution in national parks.
E.P.A. | Read more »
15. Established a minimum pollution threshold at which the E.P.A. can regulate greenhouse gas emissions from stationary sources: 3 percent of total U.S. greenhouse gas emissions. (Power plants meet this threshold, but oil and gas production facilities fall just below it.)
E.P.A. | Read more »
16. Relaxed air pollution regulations for a handful of plants that burn waste coal for electricity.
E.P.A. | Read more »
17. Repealed rules meant to reduce leaking and venting of powerful greenhouse gases known as hydrofluorocarbons from large refrigeration and air conditioning systems.
E.P.A. | Read more »
18. Directed agencies to stop using an Obama-era calculation of the social cost of carbon, which rulemakers used to estimate the long-term economic benefits of reducing carbon dioxide emissions.
Executive Order | Read more »
19. Released new guidance that allows upwind states to contribute more ozone pollution to downwind states than during the Obama-era. (The E.P.A. under Mr. Trump also rejected petitions from a handful of states over failure to address upwind states’ pollution.)
E.P.A. | Read more »
20. Withdrew guidance directing federal agencies to include greenhouse gas emissions in environmental reviews. But several district courts have ruled that emissions must be included in such reviews.
Executive Order; Council on Environmental Quality | Read more »
21. Revoked an Obama executive order that set a goal of cutting the federal government’s greenhouse gas emissions by 40 percent over 10 years.
Executive Order | Read more »
22. Repealed a requirement that state and regional authorities track tailpipe emissions from vehicles on federal highways.
Transportation Department | Read more »
23. Lifted a summertime ban on the use of E15, a gasoline blend made of 15 percent ethanol. (Burning gasoline with a higher concentration of ethanol in hot conditions increases smog.)
E.P.A. | Read more »
24. Changed rules to allow states and the E.P.A. to take longer to develop and approve plans aimed at cutting methane emissions from existing landfills.
E.P.A. | Read more »
25. Withdrew a proposed rule aimed at reducing pollutants, including air pollution, at sewage treatment plants.
E.P.A. | Read more »
26. Threw out most of a proposed policy that would have tightened pollution standards for offshore oil and gas operations and required them to use improved pollution controls.
Interior | Read more »
27. Amended Obama-era emissions standards for clay ceramics manufacturers.
E.P.A. | Read more »
28. Relaxed some Obama-era requirements for companies to monitor and repair leaks at oil and gas facilities, including exempting certain low-production wells – a significant source of methane emissions – from the requirements altogether. (Other leak regulations were eliminated.)
E.P.A. | Read more »

In progress

29. Proposed revisions to standards for carbon dioxide emissions from new, modified and reconstructed coal power plants, eliminating Obama-era restrictions that, in effect, required them to capture and store carbon dioxide emissions.
E.P.A. | Read more »
30. Proposed a rule limiting the ability of individuals and communities to challenge E.P.A.-issued pollution permits before a panel of agency judges.
E.P.A. | Read more »

Drilling and extraction

Completed

31. Made significant cuts to the borders of two national monuments in Utah and recommended border and resource-management changes to several more.
Presidential Proclamation; Interior Department | Read more »
32. Lifted an Obama-era freeze on new coal leases on public lands. In April 2019, a judge ruled that the Interior Department could not begin selling new leases without completing an environmental review. In February 2020, the agency published an assessment that concluded restarting federal coal leasing would have little environmental impact.
Executive Order; Interior Department | Read more »
33. Finalized a plan to allow oil and gas development in the Arctic National Wildlife Refuge in Alaska, a move that overturns six decades of protections for the largest remaining stretch of wilderness in the United States. The Trump administration held last-minute lease sales in December, but failed to attract major interest from fossil fuel companies.
Congress; Interior Department | Read more »
34. Opened more than 18 million acres of land for drilling in the National Petroleum Reserve in Alaska, a vast swath of public land on the Arctic Ocean. The Obama administration had designated about half of the reserve as a conservation area.
Interior Department | Read more »
35. Lifted a Clinton-era ban on logging and road construction in Tongass National Forest, Alaska, one of the largest intact temperate rain forests in the world. (The Clinton-era rule applied to much of the national forest system.)
Interior Department | Read more »
36. Approved construction of the Dakota Access pipeline, less than a mile from the Standing Rock Sioux Reservation. The Obama administration had halted the project, with the Army Corps of Engineers saying it would explore alternative routes. In 2020, a federal court reversed the Trump administration’s decision to allow the pipeline to run along its current path, but it was allowed to continue operating.
Executive Order; Army | Read more »
37. Rescinded water pollution regulations for fracking on federal and Indian lands.
Interior Department | Read more »
38. Withdrew a requirement that Gulf oil rig owners prove they can cover the costs of removing rigs once they stop producing.
Interior Department | Read more »
39. Moved the permitting process for certain projects that cross international borders, such as oil pipelines, to the office of the president from the State Department, exempting them from environmental review.
Executive Order | Read more »
40. Changed how the Federal Energy Regulatory Commission considers the indirect effects of greenhouse gas emissions in environmental reviews of pipelines.
Federal Energy Regulatory Commission | Read more »
41. Revoked an Obama-era executive order designed to preserve ocean, coastal and Great Lakes waters in favor of a policy focused on energy production and economic growth.
Executive Order | Read more »
42. Loosened offshore drilling safety regulations implemented by the Obama after following the 2010 Deepwater Horizon explosion and oil spill, including reduced testing requirements for blowout prevention systems.
Interior Department | Read more »

In progress

43. Proposed opening most of America’s coastal waters to offshore oil and gas drilling, but delayed the plan after a federal judge in 2019 ruled that reversing a ban on drilling in the Atlantic and Arctic Oceans was unlawful. Ahead of the 2020 election, Mr. Trump announced he would exempt from drilling coastal areas around Florida, a crucial battleground state, Georgia and South Carolina.
Interior Department | Read more »
44. Approved the Keystone XL pipeline rejected by President Barack Obama, but a federal judge blocked the project from going forward without an adequate environmental review process. The Supreme Court in July 2020 upheld that ruling, further delaying construction of the pipeline.
Executive Order; State Department | Read more »
45. Withdrew proposed restrictions on mining in Bristol Bay, Alaska, despite concerns over environmental impacts on salmon habitat, including a prominent fishery. In late 2020, the U.S. Army Corps of Engineers denied a permit for one proposed project, known as the Pebble Mine, noting it would “result in significant degradation of the aquatic ecosystem.”
E.P.A.; Army | Read more »
46. Proposed easing safety regulations for exploratory offshore oil and gas drilling in the Arctic that were developed after a 2013 accident.
Executive Order; Interior Department | Read more »
47. Proposed weakening a rule that increased royalty payments for oil and gas leases on public lands, bringing them in line with market value. The Obama-era policy updated a 1980s rule that critics said allowed companies to underpay the federal government. An earlier attempt by the Trump administration to reverse the Obama rule was struck down in court, but a separate court ruling exempted the coal industry from the updated pricing policy.
Interior Department | Read more »
48. Proposed easing the approval process for oil and gas drilling in national forests by curbing the power of the Forest Service to review and approve leases, among other changes.
Agriculture Department; Interior Department | Read more »
49. Approved the use of seismic air guns for gas and oil exploration in the Atlantic Ocean. The Obama administration had denied permits for such surveys, which can kill marine life and disrupt fisheries. However, the Trump administration’s permits to allow seismic surveys expired following a protracted lawsuit, ending the possibility of seismic air gun surveys in the Atlantic in the near term. Companies would need to restart the months-long permitting process.
National Oceanic and Atmospheric Administration | Read more »

Infrastructure and planning

Completed

50. Weakened the National Environmental Policy Act, one of the country’s most significant environmental laws, in order to expedite the approval of public infrastructure projects, such as roads, pipelines and telecommunications networks. The new rules shorten the time frame for completing environmental studies, limit the types of projects subject to review, and no longer require federal agencies to account for a project's cumulative effects on the environment, such as climate change.
Council on Environmental Quality | Read more »
51. Revoked Obama-era flood standards for federal infrastructure projects that required the government to account for sea level rise and other climate change effects.
Executive Order | Read more »
52. Relaxed the environmental review process for federal infrastructure projects.
Executive Order | Read more »
53. Overturned an Obama-era guidance that ended U.S. government financing for new coal plants overseas except in rare circumstances.
Executive Order; Treasury Department | Read more »
54. Revoked a directive for federal agencies to minimize impacts on water, wildlife, land and other natural resources when approving development projects.
Executive Order | Read more »
55. Revoked an Obama executive order promoting climate resilience in the northern Bering Sea region of Alaska, which withdrew local waters from oil and gas leasing and established a tribal advisory council to consult on local environmental issues.
Executive Order | Read more »
56. Reversed an update to the Bureau of Land Management’s public land-use planning process.
Congress | Read more »
57. Withdrew an Obama-era order to consider climate change in the management of natural resources in national parks.
National Park Service | Read more »
58. Restricted most Interior Department environmental studies to one year in length and a maximum of 150 pages, citing a need to reduce paperwork.
Interior Department | Read more »
59. Withdrew a number of Obama-era Interior Department climate change and conservation policies that the agency said could “burden the development or utilization of domestically produced energy resources.”
Interior Department | Read more »
60. Eliminated the use of an Obama-era planning system designed to minimize harm from oil and gas activity on sensitive landscapes, such as national parks.
Interior Department | Read more »
61. Withdrew Obama-era policies designed to maintain or, ideally, improve natural resources affected by federal projects.
Interior Department | Read more »
62. Revised the environmental review process for Forest Service projects to automatically exempt certain categories of projects, including those under 2,800 acres.
Agriculture Department | Read more »
63. Ended environmental impact reviews of natural gas export projects at the Department of Energy.
Department of Energy | Read more »

Animals

Completed

64. Rolled back a roughly 40-year-old interpretation of a policy aimed at protecting migratory birds. The rule imposed fines and other penalties on companies who accidentally kill birds through their actions, including oil spills and toxic pesticide applications. In August 2020, a federal judge rejected the Trump administration’s legal rationale for the regulation, reinstating the protection. But, in January, the administration moved forward with a final rule anyway.
Interior Department | Read more »
65. Cut critical habitat for the northern spotted owl by more than three million acres in Washington state, Oregon and Northern California, opening up the land to timber harvesting.
Interior Department | Read more »
66. Changed the way the Endangered Species Act is applied, making it more difficult to protect wildlife from long-term threats posed by climate change.
Interior Department; National Oceanic and Atmospheric Administration | Read more »
67. Weakened critical habitat protections under the Endangered Species Act by making it easier to exclude certain areas, including for public-works projects such as schools and hospitals, and for public lands leased to non-government businesses.
Interior Department | Read more »
68. Ended the automatic application of full protections for ‘threatened’ plants and animals, the classification one step below ‘endangered’ in the Endangered Species Act.
Interior Department | Read more »
69. Relaxed environmental protections for salmon and smelt in California’s Central Valley in order to free up water for farmers.
Executive Order; Interior Department | Read more »
70. Removed the gray wolf from the endangered species list.
Interior Department | Read more »
71. Overturned a ban on the use of lead ammunition and fishing tackle on federal lands.
Interior Department | Read more »
72. Overturned a ban on the hunting of predators in Alaskan wildlife refuges.
Congress | Read more »
73. Reversed an Obama-era rule that barred using bait, such as grease-soaked doughnuts, to lure and kill grizzly bears, among other sport hunting practices that many people consider extreme, on some public lands in Alaska.
National Park Service; Interior Department | Read more »
74. Amended fishing regulations to loosen restrictions on the harvest of a number of species.
National Oceanic and Atmospheric Administration | Read more »
75. Removed restrictions on commercial fishing in a protected marine preserve southeast of Cape Cod that is home to rare corals and a number of endangered sea animals. The Trump administration suggested changing the management or size of two other marine protected areas in the Pacific Ocean.
Executive Order; National Oceanic and Atmospheric Administration | Read more »
76. Proposed revising limits on the number of endangered marine mammals and sea turtles that can be unintentionally killed or injured with sword-fishing nets on the West Coast. (The Obama-era rules were initially withdrawn by the National Oceanic and Atmospheric Administration, but were later finalized following a court order. The agency said it planned to revise the limits.)
National Oceanic and Atmospheric Administration | Read more »
77. Loosened fishing restrictions intended to reduce bycatch of Atlantic Bluefin Tuna. Nonprofits have filed a lawsuit challenging the rollback.
National Oceanic and Atmospheric Administration | Read more »
78. Overturned a ban on using parts of migratory birds in handicrafts made by Alaskan Natives.
Interior Department | Read more »

In progress

79. Opened nine million acres of Western land to oil and gas drilling by weakening habitat protections for the sage grouse, an imperiled bird. A federal judge in Idaho temporarily blocked the measure, arguing the Bureau of Land Management failed to carry out an adequate environmental review for the proposal. A Montana court nullified 440 oil and gas leases in greater sage-grouse habitat, but later put the ruling on hold pending appeal. In a push to finalize the rollback before Mr. Trump leaves office, the Bureau published revised environmental impact statements in late 2020 and requested that lease sales be upheld by the Montana court.
Interior Department | Read more »

Water pollution

Completed

80. Scaled back pollution protections for certain tributaries and wetlands that were regulated under the Clean Water Act by the Obama administration. (A federal judge in Colorado halted implementation of the rule within the state, but it is in effect elsewhere.)
E.P.A.; Army | Read more »
81. Revoked a rule that prevented coal companies from dumping mining debris into local streams.
Congress | Read more »
82. Weakened a rule that aimed to limit toxic discharge from power plants into public waterways.
E.P.A. | Read more »
83. Doubled the time allowed for utilities to remove lead pipes from water systems with high levels of lead.
E.P.A. | Read more »
84. Weakened a portion of the Clean Water Act to make it easier for federal agencies to issue permits for federal projects over state objections if the projects don’t meet local water quality standards, including for pipelines and other fossil fuel facilities.
Executive Order; E.P.A. | Read more »
85. Extended the lifespan of unlined holding ponds for coal ash waste from power plants, which can spill their contents because they lack a protective underlay.
E.P.A. | Read more »
86. Allowed certain unlined coal ash holding areas to continue operating, though they were previously deemed unsafe.
E.P.A. | Read more »
87. Withdrew a proposed rule requiring groundwater protections for certain uranium mines. Recently, the administration’s Nuclear Fuel Working Group proposed opening up 1,500 acres outside the Grand Canyon to nuclear production.
E.P.A. | Read more »

In progress

88. Proposed a regulation limiting the scope of an Obama-era rule under which companies had to prove that large deposits of recycled coal ash would not harm the environment.
E.P.A. | Read more »

Toxic substances and safety

Completed

89. Rejected a proposed ban on chlorpyrifos, a pesticide linked to developmental disabilities in children. In 2020, the E.P.A. also rejected its own earlier finding that the pesticide can cause serious health problems, though it later recommended some label changes and usage restrictions. (Several states have banned use of the pesticide and its main manufacturer said it would stop producing the product because of shrinking demand.)
E.P.A. | Read more »
90. Declined to require that certain industries — including electric power, petroleum, coal products manufacturing and chemical manufacturing — have enough funds to cover major spills and accidents. (The Obama administration was planning to develop such requirements.)
E.P.A. | Read more »
91. Declined to issue a proposed rule that required the hardrock mining industry to prove it could pay to clean up future pollution.
E.P.A. | Read more »
92. Narrowed the scope of a 2016 law mandating safety assessments for potentially toxic chemicals like dry-cleaning solvents. The updated rules allowed the E.P.A. to exclude some chemical uses and types of exposure in the review process. In November 2019, a court of appeals ruled the agency must widen its scope to consider full exposure risks, but watchdog groups say it did not do so in some assessments.
E.P.A. | Read more »
93. Reversed an Obama-era rule that required braking system upgrades for “high hazard” trains hauling flammable liquids like oil and ethanol.
Transportation Department | Read more »
94. Changed safety rules to allow for rail transport of highly flammable liquefied natural gas.
Transportation Department | Read more »
95. Rolled back most of the requirements of a 2017 rule aimed at improving safety at sites that use hazardous chemicals that was instituted after a chemical plant exploded in Texas.
E.P.A. | Read more »
96. Narrowed pesticide application buffer zones that are intended to protect farmworkers and bystanders from accidental exposure.
E.P.A. | Read more »
97. Removed copper filter cake, an electronics manufacturing byproduct comprised of heavy metals, from the “hazardous waste” list.
E.P.A. | Read more »

In progress

98. Announced a review of an Obama-era rule lowering coal dust limits in mines. The head of the Mine Safety and Health Administration said there were no immediate plans to change the dust limit but extended a public comment period until 2022.
Labor Department | Read more »

Other

Completed

99. Limited the scientific and medical research the E.P.A. can use to determine public health regulations, de-emphasizing studies that do not make their underlying data publicly available. (Scientists widely criticized the proposal, saying it would effectively block the agency from considering landmark research that relies on confidential health data.)
E.P.A. | Read more »
100. Limited funding of environmental and community development projects through corporate settlements of federal lawsuits.
Justice Department | Read more »
101. Repealed an Obama-era regulation that would have nearly doubled the number of light bulbs subject to energy-efficiency standards starting in January 2020. The Energy Department also blocked the next phase of efficiency standards for general-purpose bulbs already subject to regulation.
Energy Department | Read more »
102. Weakened dishwasher energy efficiency standards by exempting fast-cleaning machines from decades-old rules.
Energy Department | Read more »
103. Loosened water and efficiency standards for showerheads and washers and dryers.
Energy Department | Read more »
104. Changed the process for how the government sets energy efficiency standards for appliances and other equipment. The new rules set an “energy savings threshold” for regulations (which environmental groups say is too high) and allow industries to set their own test procedures.
Energy Department | Read more »
105. Withdrew proposed Obama-era efficiency standards for residential furnaces and commercial water heaters that were designed to reduce energy use.
Energy Department | Read more »
106. Made it easier for appliance manufacturers to get a temporary exemption from federal energy efficiency test procedure requirements.
Energy Department | Read more »
107. Finalized a rule that limits 401(k) retirement plans from investing in funds that focus on the environment. The Obama administration had issued guidance to encourage investing in environmentally- and socially-focused funds as long as they were competitive investments.
Labor Department | Read more »
108. Changed a 25-year-old policy to allow coastal replenishment projects to use sand from protected ecosystems.
Interior Department | Read more »
109. Stopped payments to the Green Climate Fund, a United Nations program to help poorer countries reduce carbon emissions.
Executive Order | Read more »
110. Reversed restrictions on the sale of plastic water bottles in national parks designed to cut down on litter, despite a Park Service report that the effort worked.
Interior Department | Read more »

In progress

111. Froze civil penalties for companies that violate fuel efficiency standards at $5.50 for every 10th of a mile per gallon over the standards. (They were slated to increase to $14 for every 10th of a mile per gallon in model year 2019.) A federal court reinstated the higher penalty, but the Trump administration continued to delay its implementation.
Transportation Department | Read more »
112. Initially withdrew, and then delayed, a proposed rule that would inform car owners about fuel-efficient replacement tires.
Transportation Department | Read more »

Some rules were rolled back, then reinstated

These rules were initially reversed by the Trump administration but were later reinstated, often following lawsuits and other challenges.

1. Repealed the Obama-era Clean Power Plan, which would have set strict limits on carbon emissions from coal- and gas-fired power plants, and replaced it with a new version that would let states set their own rules. In the final days of Mr. Trump’s term, a federal appeals court struck down the repeal and replacement plan, arguing that the agency “fundamentally” misinterpreted its own legal obligations to regulate emissions under the Clean Air Act. The court directed the E.P.A. to start over with a new approach.
Executive Order; E.P.A. | Read more
2. Delayed issuing rules that regulate greenhouse gas emissions from aircraft, which would have echoed standards adopted by the international airline industry four years ago. The delay was challenged by environmental groups, and the rule — which critics say is far too weak today — was put forward in December 2020.
E.P.A. | Read more
3. Stopped enforcing a 2015 rule that prohibited the use of hydrofluorocarbons, powerful greenhouse gases, in air-conditioners and refrigerators. A court later partially restored the prohibition and Congress agreed to phase down production and consumption of hydrofluorocarbons in a 2020 year-end budget bill.
E.P.A. | Read more
4. Ended an Occupational Safety and Health Administration program to reduce risks of workers developing the lung disease silicosis by making it easier to conduct proactive workplace inspections. The administration delayed issuing a revised program for two and a half years, until February 2020.
Labor Department | Read more
5. Sought to repeal emissions standards for “glider” trucks — vehicles retrofitted with older, often dirtier engines — but reversed course after Andrew Wheeler took over from Scott Pruitt as head of the E.P.A.
E.P.A. | Read more
6. Delayed a compliance deadline for new national ozone pollution standards by one year, but later reversed course.
E.P.A. | Read more
7. Delayed implementation of a rule regulating the certification and training of pesticide applicators, but a judge ruled that the E.P.A. had done so illegally and declared the rule still in effect.
E.P.A. | Read more
8. Initially delayed publishing efficiency standards for household appliances, but later published them after multiple states and environmental groups sued.
Energy Department | Read more
9. Removed the Yellowstone grizzly bear from the Endangered Species List, but the protections were later reinstated by a federal judge. (The Trump administration appealed the ruling in May 2019.)
Interior Department | Read more
10. Reissued a rule limiting the discharge of mercury by dental offices into municipal sewers after a lawsuit by the Natural Resources Defense Council, an advocacy group.
E.P.A. | Read more
11. Delayed federal building efficiency standards until Sept. 30, 2017, at which time the rules went into effect.
Energy Department | Read more
12. Ordered a review of water efficiency standards in bathroom fixtures, including toilets. E.P.A. determined existing standards were sufficient.
E.P.A. | Read more

Note: This list does not include new rules proposed by the Trump administration that do not roll back previous policies, nor does it include court actions that have affected environmental policies independent of executive or legislative action.