On April 1, Senate Environment and Public Works Ranking Member David Vitter (R-LA) and Sen. Jeff Sessions (R-AL) sent a letter to the Environmental Protection Agency (EPA) on revisions to state implementation plans to control emissions during the startup and shutdown of a plant. After receiving a petition from the Sierra Club, the EPA revised 36 state implementation plans to better comply with the Clean Air Act. One day after the letter was sent the EPA announced it would extend the comment period for the proposed rule from April 11 to May 13.