Bottom line on regulating greenhouse gases under the clean air act
How can the EPA regulate GHGs? Doesn’t the Clean Air Act only apply to air pollutants? An April 2007 Supreme Court decision (Massachusetts v. EPA) ruled that GHGs are air pollutants under the Clean Air Act. The court instructed the EPA to decide whether GHG emissions endanger public health and/or welfare, or if current science is too uncertain to make a reasonable judgment. In response to the Supreme Court decision, the EPA found in April 2009 that GHG emissions do indeed endanger public health and welfare. This “endangerment finding” was made under section 202 of the Clean Air Act, which applies to motor vehicles. The EPA alsomade a “cause or contribute fi nding” that GHG emissions from motor vehicles contribute to the problem of climate change. This cause or contribute fi nding is the next step towards regulating GHG emissions from motor vehicles after the endangerment finding. If both findings are finalized, the EPA is required to move forward with regulatory rulemaking procedures.