Democrats who serve on the Senate Environment and Public Works Committee are calling on Oklahoma Attorney General (AG) Scott Pruitt, who is President-elect Trump’s pick to head the Environmental Protection Agency (EPA), to detail his ties to the oil and gas industry.

In a letter dated Tuesday and published by Politico, the senators asked Pruitt to provide details on his involvement with the Rule of Law Defense Fund, a 501(c)(4) focused on public policy issues important to Republican AGs.

The lawmakers also raised past reporting on Pruitt’s relationship to the oil and gas industry while serving as Oklahoma’s AG, citing correspondence between Pruitt’s office and Devon Energy Corp. published as part of a New York Times investigation in 2014. That exchange appeared to show that Devon had essentially written the letter Pruitt’s office sent to the EPA questioning the agency’s approach to estimating methane emissions from natural gas production.

“We have been troubled that as attorney general of Oklahoma you used, nearly verbatim, industry talking points in official correspondence your office sent to EPA concerning EPA’s estimation of methane pollution in your state,” the letter stated. “Thanks to news reporting prior to your nomination, we now know about your close relationship with Devon Energy and that you appear to have been willing to accept its representations about its business practices without independent confirmation or analysis.”

Pruitt, officially nominated for EPA administrator earlier in December, has been widely viewed as a friend to the energy industry likely to rein in an agency critics have accused of overreaching under the Obama administration. Under Pruitt, Oklahoma joined a coalition of states challenging the EPA’s Clean Power Plan in court.

Pruitt’s nomination is part of a broader shift toward a more pro-business, fossil fuel-friendly climate anticipated under the incoming Trump administration.

“Before the Senate votes to confirm you to run EPA, it is important that you provide a full disclosure of your relationship with the energy industry so we can determine how that will influence your ability to run the agency,” the lawmakers wrote. The confirmation process will provide Pruitt with “an opportunity to dispel the notion that the advocacy you have undertaken on environmental issues as attorney general of Oklahoma has been directed by and for the benefit of the energy industry.”

The letter was signed by Democrats Sheldon Whitehouse (RI), Edward Markey (MA), Jeffrey Merkley (OR), Cory Booker (NJ) and Benjamin Cardin (MD), as well as Independent Bernie Sanders (VT).