NEW YORK (Reuters) - U.S. environmental group the Sierra Club has asked the Environmental Protection Agency's inspector general to investigate whether the agency's head, Scott Pruitt, violated internal policies when he said he did not believe carbon dioxide was a major contributor to climate change, according to a letter seen by Reuters on Wednesday.
Lawyers for the Sierra Club wrote to the EPA's Office of Inspector General on Tuesday asking the independent watchdog to check whether Pruitt violated the EPA's 2012 Scientific Integrity Policy when he told a CNBC interviewer on March 9, "I would not agree that it's a primary contributor to the global warming that we see."
The request ramps up tension between the U.S. environmental movement and the administration of President Donald Trump, who has called global warming a hoax meant to weaken the U.S. economy and has packed his Cabinet with people who question the science of climate change.
An overwhelming majority of scientists think that carbon dioxide emissions from burning fossil fuels is a major contributor to global climate change, triggering sea level rise, droughts and more frequent violent storms.
"It's pretty unprecedented to have the head of the EPA contradicting basic scientific facts," Sierra Club Senior Attorney Elena Saxonhouse told Reuters on Wednesday.
In the letter, the Sierra Club's lawyers said Pruitt's comments contradicted a "comprehensive review" of scientific research on climate change and appeared to be politically motivated.
The EPA website says its policy is meant to maintain "a culture of scientific integrity for all its employees," and requires EPA officials and staff to ensure the agency's work respects the findings of the broader scientific community.
"Administrator Pruitt's comments are perfectly in keeping with the scientific integrity policy," EPA spokesman John Konkus said in an email. "There is an ongoing scientific debate on climate change, its causes and its effect. That debate should be encouraged as the Administrator has done, not discouraged as Sierra Club is attempting to do."
A spokeswoman for the EPA's inspector general said in an email the IG's office could neither confirm nor deny investigation requests.
As Oklahoma's attorney general, Pruitt sued the EPA more than a dozen times while accepting campaign donations from the energy industry. Emails released on Feb. 22 by an Oklahoma Court showed Pruitt also used language provided by an energy company in one of his challenges of the EPA over methane emissions regulations.
Sierra Club's Saxonhouse said the group believed that the EPA's scientific integrity policy applied to political appointees as well as career EPA staff, but said it was unclear how the agency could enforce it.
"It shouldn't just be a piece of paper or some words on a website. It's intended to protect the public from bad decision-making that's not based on real facts," she said.
Reporting By Emily Flitter; editing by Richard Valdmanis and Richard Chang