Scott Pruitt, administrator of the Environmental Protection Agency (EPA), greets employees of the agency in Washington, U.S., February 21, 2017. REUTERS/Joshua Roberts

WASHINGTON (Reuters) - U.S. Environmental Protection Agency chief Scott Pruitt has recused himself from several court cases that he pursued against the agency when he was Oklahoma attorney general, according to a recusal statement.

Pruitt, who had sued the environmental agency more than a dozen times when he was the oil- and gas-producing state’s top legal officer, had pledged during his Senate confirmation that he would step aside from ongoing cases if the agency’s ethics panel required it.

Environmental groups have contended that his litigation as Oklahoma attorney general may have been influenced by energy companies and industry groups that contributed to his election campaigns.

“This recusal statement addresses all of my ethics obligations,” Pruitt said in the four-page statement, which was dated May 4. It was first reported by the E&E News website, which obtained the statement under the Freedom of Information Act.

Pruitt said he would not participate for one year after his Senate confirmation in matters involving four parties. They include Oklahoma and the Rule of Law Defense Fund, a public policy group involving Republican attorneys general that targeted environmental rules.

Pruitt also recused himself from a dozen pending cases involving the EPA. They include lawsuits over the Clean Power Plan and cases in both federal appeals and district courts over the Clean Water Act, which expanded the number of federally protected waterways.

Republican President Donald Trump signed an order in March undoing the Clean Power Plan and other climate change rules that had been imposed by his predecessor, Democratic President Barack Obama.