WASHINGTON — A new coronavirus bill drafted by House Democrats will include a reform expanding liability protection for companies that sell masks after Democratic leaders dropped their opposition to that provision, The Post has learned.

House Energy and Commerce Committee Chairman Frank Pallone (D-NJ), who was perceived as the top opponent of the reform, confirmed to The Post that Democrats finally came around to agree to add liability protection.

“The House will address N95 mask liability this week,” Pallone said, confirming that a deal was reached. “Manufacturers initially requested an indefinite, blanket liability for themselves be attached to last week’s supplemental.”

Pallone added: “Since then we have been working to put together a targeted liability waiver that ensures N95 manufacturers are protected from risks associated only with the novel coronavirus. This agreement strikes the right balance and ensures that American health care workers will continue to be protected during this outbreak.”

Last-minute jockeying had appeared to threaten the reform requested by companies and pushed by the White House.

A well-placed congressional source told The Post on Wednesday that the new coronavirus package being formalized by House Speaker Nancy Pelosi (D-Calif.) was expected to include the reform. A second source, a Democratic Hill staffer, told The Post, “It’s more likely than not and we know that it’s in the mix.”

But other sources said an agreement in principle was breaking down. One source said Pelosi appeared to have gotten cold feet after Vice President Mike Pence spoke about the reform at a Tuesday night press briefing. A different source said there was a last-minute struggle over whether to include only disposable masks or also more sophisticated respiratory equipment.

Pallone did not lay out the precise details of the waiver in his statement to The Post.

Manufacturers asked for the legal change as demand and potential liability soars during the coronavirus outbreak. Democratic House leaders had blocked the change from being included in the $8.3 billion coronavirus package signed last week by President Trump.

The reform has bipartisan backing, but Republicans used increasingly tough language to denounce Democrats as the bill was finalized. Sen. Tom Cotton (R-Ark.) tweeted Wednesday that “[Pallone] and the Democrats are putting ambulance-chasing lawyers ahead of our doctors and nurses in the middle of a pandemic.”

The legal reform would change the 2005 Public Readiness and Emergency Preparedness Act, which already has liability protection for a more limited subset of N95 respiratory masks.

Proponents say the Centers for Disease Control and Prevention recommends any certified N95 mask to protect against the virus. All N95 masks are certified to filter 95 percent of particles from the air, but surgical masks covered by the 2005 law also have splash protection.

Industrial N95 masks often are a firm, rounded white shell. They are a common sight at dusty construction sites and can protect against coronavirus, but companies say there’s unease among businesses as demand soars.

“God forbid, if someone wears the respirator and ends up with the virus, I don’t want to have that liability of potentially being sued,” said David Young, president of A&M Industrial, a major supplier of masks and other protective gear in New Jersey and New York.

Young’s 100-person staff supplies many companies and government buyers, and is running low on masks, and he said increasing the variety of available product might increase supply.

“We face an unprecedented demand for these kind of products and it extends beyond our normal customer base: It’s the local community, it’s municipalities, it’s school districts, it’s regular consumers. And we want to do the right thing and provide these products,” Young said.

Major mask-maker 3M said in a statement: “This will benefit hospitals, state and local governments, distributors, and other entities, along with manufacturers.”

Upstate Rep. Paul Tonko, a Democrat, was a leader of the push, and told The Post he was “hopeful we can work together to quickly pass this legislation and respond to the current needs of our medical professionals.”

“Ensuring adequate supply of personal protective equipment, such as N95 respirators, is a critical part of protecting our frontline health care workers during the coronavirus outbreak,” Tonko said.

Consumers can still sue if the reform happens, but they have to sue the feds. Chamber of Commerce vice president Bryan Quigley, whose group pushed the reform with the White House, said there’s historical precedent with vaccinations for transferring liability to the government, allowing industry to avoid bankrupting lawsuits to promote public health.

Charles Johnson, president of the International Safety Equipment Association trade group, told The Post that the reform sought by companies would apply only in declared public health emergencies when there’s a government recommendation to use the equipment.

“This isn’t the industry cowboying around, then saying, ‘Whoops, don’t sue us,'” Johnson said.