President Donald Trump has taken historically unprecedented action to roll back a slew of environmental regulations that protect air, water, land and public health from climate change and fossil fuel pollution.
The administration has targeted about 85 environmental rules, according to Harvard Law School's rollback tracker.
Existing environment regulations are meant to curb greenhouse gas emissions, protect land and animals from oil and gas drilling and development, as well as limit pollution and toxic waste runoff into the country's water. The administration views many of them as onerous to fossil fuel companies and other major industries.
However, the consequences of eliminating these regulations include more premature deaths from pollutants and higher levels of climate change-inducing greenhouse gas emissions, according to research from the NYU Law School.
Here are five major environmental rollback stories of 2019 that highlight the administration's efforts to loosen restrictions on methane emissions, power plants and automobile tailpipes, as well protections for endangered animals and clean water in the U.S.
The Trump administration in August announced plans to significantly weaken regulation on climate-changing methane emissions. If adopted, the government would no longer have to require oil and gas companies to implement technology to monitor and fix methane leaks from facilities and pipelines. The rule would also open debate on whether the Environmental Protection Agency can regulate methane as a pollutant.
Methane is dangerous because large amounts of it are escaping from oil and gas sites across the country and accelerating global warming. Methane levels have soared since 2007, with natural gas production as a primary suspect.
The Trump EPA argued that the proposal will save the oil and gas industry $17 million to $19 million annually in compliance costs and remove "unnecessary" burdens.
By the agency's calculations, the rollback would increase methane emissions by 370,000 tons over roughly five years. Scientists and environmental advocates called the proposal an "assault" on the environment and a major setback in the fight against climate change.
The EPA in September repealed a major Obama-era clean water regulation that curbed the amount of pollution and chemicals in the country's rivers, lakes, streams and wetlands.
The repeal allows polluters to discharge toxic substances into waterways without a permit, which could significantly harm the country's sources of safe drinking water and habitats for wildlife. The Obama-era rule had aimed to protect 60% of the country's water bodies from contamination and keep drinking water safe for about one-third of the country.
The repeal is a win for some farmers and rural landowners who no longer need a permit to use pesticides and fertilizers that could run off into water or are restricted from some types of plowing and planting.
EPA Administrator Andrew Wheeler said the rollback would allow farmers to "spend less time and money determining whether they need a federal permit and more time building infrastructure." The administration also argues that the repeal would promote economic growth and minimize regulatory uncertainty.
The Trump administration said in August it would change the rules for the Endangered Species Act, making it harder to protect wildlife from threats of human development and global warming.
The new rules make it easier to take out protections for threatened animals and plants and allow federal agencies to conduct economic assessments when deciding whether to protect a species from things like construction projects in a critical habitat. The rules also remove tools used by scientists to predict future harm to species from climate change.
The administration said the changes would make the legislation more efficient and decrease burdens on landowners and companies.
Revealing the cost of protecting wildlife could open new threats to endangered species and habitats. Since it was signed into law 45 years ago, the Endangered Species Act has been credited with rescuing species like the bald eagle, grizzly bear, Florida manatee and humpback whale.
Attorneys general in 17 states have sued the Trump administration over the changes.
The Trump administration in June implemented a rule that will keep coal-powered plants open longer, replacing an Obama-era climate effort to reduce planet-warming carbon dioxide emissions and continuing the administration's efforts to ease regulatory burdens for the coal industry.
The so-called Affordable Clean Energy rule gives states more power to decide how to control emissions and less authority to the federal government in setting emissions standards. One of the administration's goals is to allow coal power plants a chance to remain in business despite the rise in other forms of energy generation such as natural gas and solar.
In response, 29 cities and states sued the EPA's replacement of the Obama administration's Clean Power Plan, arguing it extends U.S. dependence on coal power and blocks states from pursuing clean energy production.
The case could reach the U.S. Supreme Court, setting up major implications for efforts to mitigate climate change. If the court favors the Trump administration, the rule would weaken the ability of future administrations to regulate pollution from power plants and global warming.
The White House this year also prepared to eliminate an Obama-era regulation in place to reduce automobile emissions that contribute to global warming. The administration argues that the rollback is necessary for economic and safety reasons, though environmentalists say consumers would spend billions more in fuel costs and accelerate climate change.
Four of the world's largest automakers responded in July by striking a deal with California to reduce vehicle emissions. California and 13 other states promised to continue enforcing the stricter rule, a move that could split the country's auto market and set up a financial headache for automakers.
Later in September, the administration barred California from setting its own emissions standards, which officials said would give people access to cheaper and safer vehicles. The state has set tougher emissions standards that essentially directed the industry to begin unveiling zero-emissions vehicles and battery-electric and hydrogen-powered cars.
California and 22 other states sued to challenge the administration's decision, setting up a legal fight that could reach the Supreme Court.