Senate Majority Leader Chuck Schumer and 22 other Democratic senators are calling on the Justice Department to prevent and prosecute alleged collusion and price-fixing in the oil industry.

The FTC said earlier this month that Scott Sheffield, the former CEO of Pioneer Natural Resources, colluded with OPEC and OPEC+ to potentially raise crude oil prices. Sheffield retired from the company in 2016 but returned as CEO in 2019. After retiring again in 2023, he continued to serve on its board.

The FTC cleared Exxon Mobil’s $60 billion deal to buy Pioneer on May 2 but barred Sheffield from joining the new company’s board of directors. Pioneer, which is based in Dallas, said it disagreed with the allegations but would not impede closing of the merger, which was announced in 2023.