Environment and Public Works Committee Chairwoman Boxer (D-CA) failed to hold a vote today to issue a subpoena that would make public EPA's draft endangerment finding on greenhouse gas emissions. After not being able to hold the vote, Sen. Boxer instead released materials from the draft endangerment finding, including its conclusion, which states, "In sum, the administration is proposing to find that elevated levels of greenhouse gas concentrations may reasonably be anticipated to endanger public health."

If the finding in this draft endangerment finding--that elevated levels of greenhouse gas concentrations may reasonably be anticipated to endanger public health—is officially made by EPA, the repercussions under the Clean Air Act could be significant. Under the Clean Air Act, a finding that the emission of a particular pollutant may reasonably be anticipated to endanger public health typically places a nondiscretionary duty on EPA to promulgate regulations restricting the emissions of that pollutant to a level that is protective of public health and welfare. In Massachusetts v. EPA, the Supreme Court held that greenhouse gases are pollutants and, over objections from EPA regarding the scope of the potential regulatory consequences, ordered EPA to determine whether the emission of greenhouse gases may reasonably be anticipated to endanger public health. Thus, the significance of the draft endangerment finding is apparent: If its language was released officially, EPA would likely be required to regulate greenhouse gases under the Clean Air Act.