The Supreme Court building

Massachusetts v. EPA

  • 2005

    In 2005, a mul­ti-state coali­tion led by Mass­a­chu­setts Attor­ney Gen­er­al Martha Coak­ley sued the Envi­ron­men­tal Pro­tec­tion Agency (EPA) over its 2003 deter­mi­na­tion that the EPA lacked the legal author­i­ty to reg­u­late car­bon pol­lu­tion and oth­er forms of green­house gas­es (GHGs) under the Clean Air Act. In addi­tion to Mass­a­chu­setts, state attor­neys gen­er­al of Cal­i­for­nia, Con­necti­cut, Illi­nois, Maine, New Jer­sey, New Mex­i­co, New York, Ore­gon, Rhode Island, Ver­mont and Wash­ing­ton joined the mul­ti-state coalition.

  • 2007

    The U.S. Supreme Court con­firmed, in Mass­a­chu­setts v. EPA, 549 U.S. 497 (2007), that the Clean Air Act’s broad def­i­n­i­tion of air pol­lu­tants cov­ers green­house gas­es, which cause cli­mate change. The Supreme Court also con­firmed that if the EPA makes a so-called endan­ger­ment find­ing,” and con­cludes that GHGs pose a dan­ger to human health or the envi­ron­ment, it must act to reduce such emissions.

  • 2009

    In 2009, the EPA issued an Endan­ger­ment Find­ing cov­er­ing car­bon diox­ide and oth­er green­house gas­es, requir­ing the agency to devel­op a plan to reduce GHG emissions.