Two vulnerable House Democrats are suggesting that their support for the Manchin-Schumer social spending and taxation bill may be uncertain after an energy fee that would fine fossil fuel companies for their methane emissions was included in the Senate bill.

The fee, known as the Inflation Reduction Act Methane Emissions Charge, has been a thorn in the side for some Democrats, specifically those representing vulnerable districts in Texas with a heavy oil and gas industry presence, and could end up being the deciding factor on whether the bill ultimately passes or fails in the House.

The bill, officially called the Inflation Reduction Act, passed along party lines in the Senate over the weekend could face doom if just a handful of House Democrats join Republicans in voting against it.

Texas Democrats Rep. Henry Cuellar, Rep. Vicente Gonzalez, and then-Rep. Filemon Vela wrote a letter to House Speaker Nancy Pelosi last year complaining the fee, which was included in the earlier version of the House "Build Back Better" legislation, "unfairly targets oil and gas companies" and that it would hurt the ability for the U.S. to be competitive in the world energy market.

INFLATION REDUCTION ACT: WHAT TAX HIKES ARE IN THE BILL?

Democratic Texas Rep. Henry Cuellar walks on Capitol Hill

Rep. Henry Cuellar, D-Texas, is seen after a meeting of the House Democratic Caucus in the U.S. Capitol on Wednesday, June 8, 2022. (Tom Williams/CQ-Roll Call, Inc via Getty Images)

It's unclear if Gonzalez and Cuellar's opposition to the fee has worn off after the scaled-back version of the bill passed the Senate with the fee included, and both appear to be waiting to see how conversations surrounding it shake out as the week progresses.

"My priority is ensuring this bill would not raise energy prices or hinder American energy jobs at such a critical time," Gonzalez told The Texas Tribune over the weekend. "These are the people and values I represent and will continue to fight for."

He admitted, however, that there were "still come concerning provisions" contained within it.

In a separate statement to Fox News Digital, Gonzalez expressed optimism towards the bill, describing it as "much needed," and said it contained provisions that would help certain constituents. He stopped short, however, of saying he would support it in its current form.

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Texas Democrat Vicente Gonzalez

Rep. Vicente Gonzalez, D-Texas, attends a House Financial Services Committee hearing titled Monetary Policy and the State of the Economy featuring testimony by Federal Reserve Chairman Jerome Powell in Rayburn Building on February 27, 2018. (Tom Williams/CQ Roll Call/ Getty Images)

"Democrats are continuing to deliver for the American people. I look forward to working with my House colleagues as we return to Washington to work on this much needed legislation," he said.

"There are provisions in this bill that will help our seniors and those on fixed incomes like lowering prescription drug prices and capping insulin for those on Medicare. I will be sure to fight for South Texans and make sure no one is left behind," he added.

Fox News Digital also reached out to Cuellar for comment but did not hear back by publishing time.