Endangerment finding repeal alters EPA authority to limit greenhouse gases.

On Feb. 12 the Trump administration rescinded the endangerment finding that gave the EPA the legal basis to regulate greenhouse gases; experts say that decision removes a key basis for federal emissions rules and could affect health protections tied to cleaner air.

On Feb. 12 the Trump administration rescinded the endangerment finding, the scientific and legal determination that certain greenhouse gases threaten public health and welfare. That finding, first issued in 2009, has been the basis for EPA authority under the Clean Air Act to regulate emissions from vehicles, power plants, and other sources. Its repeal has prompted discussion among researchers and public health experts about how fewer federal restrictions on emissions could affect air quality and climate-related health risks. The topic is being discussed because air pollution and greenhouse gases are linked to documented harms such as asthma, heart and lung disease, and health effects from extreme heat and wildfires. Key points: - The endangerment finding established that carbon dioxide, methane, and other greenhouse gases "threaten the public health and welfare," and supported EPA regulatory actions under the Clean Air Act. - The administration announced the finding was rescinded on Feb. 12, removing that formal basis for many federal greenhouse gas rules. - Public health researchers note that reduced regulation of emissions can increase unhealthy air pollutants such as fine particulate matter (PM2.5), which is linked to higher risks of early death, chronic cardiovascular and respiratory disease, and higher asthma risk in children. - Legal observers and experts have indicated that courts or legal challenges may address the repeal and the policies built on the original finding. Summary: The repeal removes a central legal and scientific basis the EPA has used to limit greenhouse gas emissions, and researchers report connections between those emissions, air pollution, and various health harms. Legal outcomes and the practical effects on federal emissions rules are not settled. Undetermined at this time.