The Environmental Protection Agency (EPA) on July 29 denied 10 petitions challenging its 2009 finding that climate change caused by greenhouse gases poses a threat to human health and the environment. EPA made the endangerment finding in response to a 2007 Supreme Court case that held that greenhouse gases are air pollutants under the Clean Air Act, and are therefore subject to regulation by EPA.

The petitions, filed by GOP attorneys general from Texas and Virginia, the U.S. Chamber of Commerce and other conservative groups, alleged that the endangerment finding was based on faulty science, and that attempts to regulate greenhouse gases would be harmful to the economy. The petitions were in large part focused on the groups’ claim that stolen emails from climate scientists revealed a conspiracy to cover up evidence that could call into question the science behind climate change.

EPA Administrator Lisa Jackson shot back at these allegations in a strongly worded statement announcing EPA’s decision. “The endangerment finding is based on years of science from the U.S. and around the world. These petitions -- based as they are on selectively edited, out-of-context data and a manufactured controversy -- provide no evidence to undermine our determination. Excess greenhouse gases are a threat to our health and welfare,” said Jackson. “Defenders of the status quo will try to slow our efforts to get America running on clean energy. A better solution would be to join the vast majority of the American people who want to see more green jobs, more clean energy innovation and an end to the oil addiction that pollutes our planet and jeopardizes our national security.”

Environmental groups have hailed EPA’s decision. “Today, the EPA took the U.S. Chamber of Commerce and other climate deniers to school,” said Sierra Club Executive Director Michael Brune. “Lisa Jackson’s announcement demonstrates once again the undeniable scientific evidence linking greenhouse gas emissions and pollutants to climate change and public health issues.” But opponents to greenhouse gas regulation are still attacking EPA on all fronts. Industry groups have filed a barrage of lawsuits against EPA’s efforts to protect public health from greenhouse gases, and members of Congress have made numerous attempts to pass legislation that would limit or overturn the finding.

The most recent of these attacks comes once again from Senator Lisa Murkowski (R-Alaska), who earlier this week proposed an amendment to a small business bill that would delay regulation of greenhouse gases for two years. Last month, Murkowski tried and failed to pass a resolution that would have overturned the endangerment finding entirely. It is unlikely that Murkowski’s latest effort to block the rule will succeed. Even if the proposed amendment survives, any attempt to suspend greenhouse gas regulations will be met by a veto, a White House official said last week.