The attorneys general for eleven US states and the District of Columbia submitted a comment letter to the US Environmental Protection Agency (EPA) Monday, demanding that the agency regulate airplane exhaust pollution more strictly than the Trump administration proposed.

During the Obama administration, the EPA first proposed regulating emissions of greenhouse gasses from airplanes in 2011 and promulgated a final rule in 2016 requiring the agency to begin to regulate aircraft exhaust pollution. In late July this year, the agency announced its proposed final rule on greenhouse emission standards for aircrafts manufactured in the US, with EPA Administrator Andrew Wheeler describing it as a compromise between “safeguarding American jobs and the economy” and “regulat[ing] greenhouse gases” in a press release touting the rule’s publication. The proposed rule would require newly-designed aircrafts to meet International Civil Aviation Organization (ICAO) emission targets starting in 2020, while allowing manufacturers to continue producing existing designs without modification until 2028. In addition, the rule requires the Federal Aviation Administration to undertake enforcement of the standards, to promulgate its own rules for enforcement and adding further delay to the implementation of any regulation of airplane exhaust emissions.

Led by California Attorney General Xavier Becerra, the group of attorneys general asserted that the proposed rule is woefully inadequate to meet necessary carbon reduction targets in order to mitigate the effects of climate change. In a press release, Becerra described the proposed rule as a “sham” and said that failure to regulate aircraft emissions more stringently is not in accordance with the Clean Air Act. According to the letter, the ICAO standards that the EPA adopted were already out-of-date when the agency first proposed the rulemaking in 2016, and they now lag at least a decade behind current technology. As a result, the standards coming into effect in 2028 would require no changes to currently existing designs, effectively resulting in no mitigation of greenhouse gas emissions, a violation of the Clean Air Act’s mandate requiring that the EPA regulate pollutants. In addition, the letter identifies a number of procedural errors with the agency’s promulgation, such as failing to consider issues of federalism and environmental justice as required by EPA’s own rulemaking procedures. The letter requests that the proposed final rule be withdrawn and properly modified to adopt stricter standards.

The states of Connecticut, Illinois, Maryland, Massachusetts, Minnesota, New Jersey, New York, Oregon, Vermont, and Washington and the District of Columbia joined Becerra’s letter.