On May 7, Rep. Henry Waxman (D-CA) and Sen. Sheldon Whitehouse (D-RI) sent a letter to the Environmental Protection Agency (EPA) criticizing the agency’s recent decision to not conduct an endangerment finding that could result in coal mine performance standards. In 2010, environmental groups including the Center for Biological Diversity and the Sierra Club petitioned the EPA to conduct an environmental finding and to establish performance standards for methane, a greenhouse gas. On May 8, the EPA announced it lacked the time or resources to conduct a study. Rep. Waxman and Sen. Whitehouse said the decision would increase the public health risk.