Senate Majority Leader Chuck Schumer is urging the US Federal Trade Commission to look into whether Exxon Mobil Corp. and Chevron Corp.’s proposed oil and gas acquisitions could violate antitrust laws.

Schumer in a letter on Wednesday said Exxon’s proposed $60 billion acquisition of Pioneer Natural Resources Co. and Chevron’s proposed $53 billion acquisition of Hess Corp. — two of the largest oil and gas deals of this century — are “likely to harm competition.”

“Should the FTC determine that these mergers would violate antitrust law, we urge you to oppose them,” Schumer wrote in the letter to FTC Chair Lina Khan. Other Democrats who signed the letter include Richard Blumenthal of Connecticut, Cory Booker of New Jersey, Tammy Duckworth of Illinois, John Fetterman of Pennsylvania and Amy Klobuchar of Minnesota.

Schumer’s outreach marks the highest-profile opposition to the deals on Capitol Hill so far. In the letter, Schumer cited concerns that the pair of acquisitions could harm consumers by driving up gas prices — a particularly concerning dynamic as most Americans who rely on their cars cannot choose to stop paying for gas.

The deals could significantly alter the US oil and gas landscape. Chevron’s acquisition of Hess will give the company a large foothold in Guyana, the South American country that is one of the world’s newest oil producers. And Exxon’s acquisition of Pioneer will enable the company to become the dominant producer of shale oil, solidifying the US oil companies’ hold on the western hemisphere’s most prolific oil field, the Permian Basin.

Schumer asked the FTC to consider “how Exxon’s or Chevron’s vertically integrated operations may harm American competition in any national or regional market.”

The White House in 2021 urged the FTC to scrutinize deals in the oil and gas sector. The agency has since slowed down the approval of smaller oil and gas mergers, but it hasn’t sued to prevent an acquisition in the sector for years.