A letter sent to House Speaker Nancy Pelosi protesting provisions in the Democratic plan was signed by Reps. Henry Cuellar, Vicente Gonzales, Lizzie Fletcher, Sylvia Garcia, Marc Veasey, Filemon Vela and Colin Allred.

“These taxes and fees, as well as the exclusion of natural gas production from clean energy initiatives, constitute punitive practices,″ the lawmakers said in the letter.

They have been joined by other Democrats in protesting the plan, including Sens. Joe Manchin of West Virginia and Kyrsten Sinema of Arizona. Manchin has been unwilling to risk jobs in coal and oil in his state, saying the cost of the Democratic plan is too high.

For more reporting from the Associated Press, see below.

President Joe Biden and Democrats are pursuing a sweeping $3.5 trillion federal overhaul that includes landmark measures to address climate change and reduce greenhouse gas emissions in what would be the most consequential environmental policies ever enacted, after years of fits and starts.

Sidelined after the former administration withdrew from the landmark Paris climate accord — the 2015 global effort to confront climate change — the U.S. has returned to the arena, with Biden promising world leaders in April that the U.S. would cut carbon pollution in half by 2030.

But following through on Biden’s climate goals depends in large part on passage of the Democratic package, and it will take the White House’s heft to close the deal between centrist and progressive lawmakers, including disputes over its climate provisions.

“That’s where he earns his legacy,” Rep. Jared Huffman, D-Calif., said of Biden.

As Democrats rush to finish a package that touches almost all aspects of American life, the proposals related to climate change are proving to be a sticking point, particularly among key centrist lawmakers.

The president was meeting Tuesday with Manchin and Sinema as Democrats chip away at the package’s overall price tag and marshal support. With Republicans in lockstep against the plan, Democrats have few votes to spare as they try to pass it on their own.

“This is Speaker Pelosi’s grand socialist agenda to destroy freedom and embolden our enemies on the backs of American families,″ said Rep. Cathy McMorris Rogers of Washington state, the top Republican on the House Energy and Commerce panel.

Yet, for many Democrats, and voters who elected them — the climate provisions are among the most important elements of the sweeping bill.

“This is a ‘Code Red’ moment, but Democrats are answering the call,’’ said Rep. Kathy Castor, D-Florida, chairwoman of a special House committee on climate change.

“Our only hope to avoid catastrophe is to act with urgency – to act now,’’ Castor said Tuesday at the Capitol. She called climate change “a clear and present danger to American families who are facing brutal heat waves, devastating floods, failed electric grids and historic wildfires.’'

The Democratic plan will make historic investments in clean energy, climate resilience and environmental justice, she said. “We have to get this right.''

Included in the massive legislation is a nationwide clean-electricity program that is intended to eliminate climate-damaging fossil fuel emissions from U.S. power plants by 2035 — catching up to requirements already set in some states.

The proposal would spend billions to install 500,000 electric vehicle charging stations and upgrade the power grid to make it more resilient during hurricanes and other extreme weather events that are increasing and intensifying as a result of climate change.

The measure also would create a New Deal-style Civilian Climate Corps to unleash an army of young people to work in public lands and restoration projects.

“The climate crisis is here, and the cost of inaction is already staggering,” said Energy and Commerce Chair Frank Pallone, D-N.J.

A slimmer $1 trillion bipartisan infrastructure bill the House is set to consider Thursday addresses some of these priorities, with money for climate resiliency, water system upgrades and other provisions.

But progressive Democrats say a far more comprehensive approach is needed if the U.S is to have a chance to achieve Biden’s goal of cutting the nation’s greenhouse gas emissions in half, leaving both packages at a standstill as talks continue behind the scenes.

“It’s about the livability of this planet,″ said Huffman, a progressive caucus member who said Democrats were “unwilling to just be steamrolled on that.”

Overall, the Biden package aims to provide more than $600 billion to tackle climate change and lower greenhouse gas emissions, funded in large part by taxes on corporations, the wealthy and other fees, keeping to Biden’s pledge not to raise taxes on anyone earning less than $400,000 a year.

Environmental groups have hailed the overall package, calling it a once-in-a-generation opportunity.

“Investing in new clean energy technologies is one of the best things we can do to create good jobs for regular people right now while reaping long-term benefits and a healthier planet for decades to come,” said Matthew Davis of the League of Conservation Voters.

The clean-energy standard alone could create millions of jobs, while driving the U.S. electricity sector toward zero-carbon emissions, Davis and other advocates said.