Citing a report that Obama-era environmental enforcement against Devon Energy Corp. could be rolled back, a high-ranking Senate Democrat is once again questioning Environmental Protection Agency (EPA) Administrator Scott Pruitt over his ties to the Oklahoma City-based operator.

On Monday Sen. Tom Carper (D-DE), the ranking member of the Senate Environment and Public Works Committee, questioned the EPA chief over a letter from Devon — published recently as part of a New York Times report — in which the company stated that it is no longer willing to install emissions reduction equipment at its Beaver Creek gas processing plant in Wyoming.

In the letter from Devon, dated Feb. 22, shortly after Pruitt was confirmed, the producer also called for a reduced financial penalty over alleged violations at the plant.

Carper, in his letter to Pruitt Monday, said the Times report “describes an abrupt reversal in willingness by Devon Energy to install technology to detect and reduce emissions of harmful air pollutants since you were sworn in” as EPA administrator.

In the Feb. 22 letter to the Department of Justice and Wyoming state regulators, attorneys representing Devon proposed several changes to a settlement over the alleged emissions violations. The company argued that EPA had overestimated the amount of emissions from the plant. Attorneys also argued that EPA had “greatly” overstated the economic benefits to Devon for delaying compliance, as the “real” benefits were closer to $25,000 instead of the $100,000 figure provided by the agency.

“Due to the downturn in the natural gas market, sour gas processing operations at the plant have been discontinued and there has been a reduction in the number of employees at the plant,” Devon’s counsel wrote. “This has resulted in a significant reduction in the amount of gas processed…For an older, smaller, marginal plant such as Beaver Creek it is simply not feasible for Devon to commit to implement the kinds of projects previously discussed.

“…In reevaluating the settlement posture, Devon has also revisited the underlying factors which are relevant to an appropriate penalty and believes a significantly lower penalty than that which has been previously discussed is warranted in this case.”

The company said the violations resulted “from a misinterpretation of complicated regulations, not a deliberate attempt to circumvent the rules.” As an alternative project to reduce emissions, Devon proposed replacing one of the older compressors at the plant, estimated to cost $110,000.

Carper has requested additional information related to Pruitt’s handling of enforcement as EPA administrator and details of any pending or settled enforcement actions against Devon in particular.

“During your confirmation hearing, you asked, ‘What could be more important than protecting our nation’s waters, improving our air and managing the land that we have been blessed with as a nation, all the while protecting the health and welfare of our people?’ You additionally noted that ‘Clearly, the mission of the EPA, as I indicated in my opening statement, to protect our natural resources, protecting our water quality, improving our air, helping protect the health and welfare of our citizens, is key to the leadership of the EPA, and, where enforcement is necessary, vigorous enforcement,'” Carper wrote.

“Allowing Devon Energy to back out of both a remedy to ‘improve our air’ and no longer be subject to ‘vigorous enforcement’ for violations of the Clean Air Act would seem inconsistent with the statements you made to the Environment and Public Works Committee.”

Since his nomination last December, Democratic lawmakers haveheavily scrutinized Pruitt’s ties to the energy industry, pointing to his time as Oklahoma’s attorney general. They have highlighted a Times investigation published in 2014 that showed Pruitt’s office had copied onto its letterhead language written by Devon questioning the EPA over its estimations of methane emissions from the oil and gas industry.

For his part, Pruitt has endorsed a more conservative approach to interpreting Congressional intent and the statutory authority of the EPA. Since taking over, Pruitt has taken steps to roll back Obama-era regulations on methane emissions from the oil and gas industry and the controversial Waters of the United States rule.