CNN  —  Senate Majority Leader Chuck Schumer and nearly two dozen Democrats pressed the Justice Department on Thursday to launch an industry-wide investigation into Big Oil for alleged collusion and price fixing. In a letter to Attorney General Merrick Garland, Schumer and his colleagues expressed “serious concern” about “alarming” allegations from federal regulators that a Texas oil tycoon tried to conspire with OPEC to inflate oil and gasoline prices. “The federal government must use every tool to prevent and prosecute collusion and price fixing that may have increased gasoline, diesel fuel, heating oil and jet fuel costs in a way that has materially harmed virtually every American household and business,” the letter from Senate Democrats said. The lawmakers urged the DOJ to investigate the oil industry, “hold accountable any liable actors” and halt illegal activity. The letter, led by Schumer, was signed by 22 other senators, including Sens. Elizabeth Warren, Amy Klobuchar, Bernie Sanders and Dick Durbin. The letter shows how Democrats are stepping up pressure on Big Oil following bombshell accusations earlier this month by the Federal Trade Commission against Scott Sheffield, the longtime CEO of a leading Texas oil producer. Last week, congressional Democrats launched an investigation into whether other US oil companies colluded with each other and OPEC. The FTC accused Sheffield, the founder of Pioneer Natural Resources, of attempting to collude with OPEC and its allies to keep supply low — a charge the former CEO has strongly denied. Regulators cited hundreds of text messages Sheffield exchanged with OPEC officials discussing pricing, production and oil market dynamics. Sheffield “held repeated, private conversations with high-ranking OPEC representatives assuring them that Pioneer and its Permian Basin rivals were working hard to keep oil output artificially low,” the FTC found in its investigation. “The strategy appears to have worked,” Schumer and his colleagues wrote to the DOJ. The lawmakers argued that “industry collusion” may have contributed to sharply lowering US oil production, boosting gas prices by 94 cents a gallon from pre-pandemic times to today and costing the average household up to $500 per car in annual fuel costs. Schumer and his colleagues said that while the FTC has banned Sheffield from serving on Exxon’s board following its takeover of Pioneer, “only the DOJ can prosecute and fully redress the alleged anticompetitive behavior in the oil sector.” The lawmakers noted that the Sherman Act calls for a fine of up to $100 million for corporations and up to $1 million and 10 years in prison for individuals guilty of price fixing. “The DOJ must protect consumers, small businesses, and the public from petroleum-market collusion, and an important part of that mission means seeking full restitution and imposing all penalties supported by the facts and the law,” Schumer and his colleagues wrote. Sheffield responded to the FTC’s allegations on Tuesday by arguing the agency mischaracterized the facts and evidence and calling for it to rescind the order against the former CEO. In a statement, Sheffield said the FTC is “wrong to imply that I ever engaged in, promoted or even suggested any form of anti-competitive behavior.” “Publicly and unjustifiably vilifying me will have a chilling effect on the ability of business leaders in any sector of our economy to address shareholder demands and to exercise their constitutionally protected right to advocate for their industries,” Sheffield said.