Massachusetts v. EPA, 549 U.S.



The Clean Air Act allows the Environmental Protection Agency to regulate greenhouses gases because they qualify as air pollutants. Also, standing requires showing a concrete harm that can be traced to the defendant and remedied by the courts.


Twelve states as well as various cities and organizations sought to require the Environmental Protection Agency (EPA) to regulate greenhouse gases like carbon dioxide under its authority to regulate pollutants. The lawsuit was based on Section 202(a)(1) of the Clean Air Act, a provision that requires the EPA Administrator to set emission standards for air pollutants from motor vehicles that the Administrator judges to play a role in pollution that could be reasonably expected to endanger public health or welfare.

Responding to that mandate, the EPA had decided that it lacked authority to regulate greenhouse gases like carbon dioxide for climate change purposes. Even if it did have that authority, it felt that it was unnecessary to set greenhouse gas emissions standards for vehicles. The case combined the substantive issue of whether the agency had decided correctly on these issues with the procedural question of whether the states, cities, and organizations even had standing to bring such a claim. The concrete injury that they alleged was the loss of coastline to rising sea levels in global warming.