Companies have made tens of billions of dollars creating and using toxic “forever chemicals” known as PFAS, creating the biggest environmental contamination crisis in human history. PFAS makers and users have contaminated the blood of every living creature on the planet with chemicals that will never break down and have been linked to cancer and other serious health problems.

Many of these companies hid the risks of PFAS, an abbreviation for perfluoroalkyl and polyfluoroalkyl substances, from their workers and their regulators. The lethal impacts of PFAS might still be a secret if not for the efforts of legendary environmental attorney Robert Bilott, who I was proud to portray in the movie “Dark Waters.”

Now that the scope of this environmental crime has been revealed, many companies are seeking exemptions from our federal cleanup laws.

Congress and the Biden administration must not let PFAS polluters shirk their responsibility to clean up their mess. Exempting some polluters from sharing the cost of cleaning up Superfund sites, as some members of Congress have proposed, will leave other companies and taxpayers bearing the cost. These PFAS “polluter holiday” bills will also undermine the “polluter pays” principle that encourages polluters to think twice before they dump their toxic wastes on the rest of us.

None of us volunteered to have a toxic forever chemical in our blood. We’ve all been victims of the polluters who hid the risks of PFAS and the victims of the regulators who have looked the other way.

But thanks to heroes like Bilott, millions of us now know that we’ve been poisoned without our knowledge or consent. We know that PFAS are building up in our blood and organs. We know that PFAS have contaminated the drinking water of more than 200 million Americans. We know that some of the most contaminated sites are in our defense communities, which have been disproportionately impacted by toxic chemicals for too long.

But sounding the alarm is not enough. We need to hold PFAS polluters accountable. We can’t allow favored industries — regardless of how sympathetic they may be — to escape their responsibility.

Fortunately, President Biden’s Environmental Protection Agency (EPA) has made clear that only the real polluters will be required to help pay for the cost of cleaning up the most contaminated sites. No administration has done more to address the PFAS contamination crisis than the Biden administration. In particular, the Biden administration has proposed a first-ever national drinking water standard for six PFAS, which would be toughest in the world when finalized.

The Biden EPA has also proposed to designate the two most notorious PFAS — PFOA and PFOS — as hazardous substances. But that designation, which triggers responsibility for cleanup costs under Superfund, has also set off a rush by some in industry to weaken our landmark cleanup laws.

Now, Biden faces an important challenge: to face down the polluters and their lackeys in Congress. Since enacting the Superfund law, Congress has never exempted favored industries from Superfund. Creating first-ever loopholes in the law for PFAS polluters will open a Pandora’s box of exemptions for other polluters and their toxic wastes.

Biden should not wait to tell Congress he will reject bills that create polluters holidays for PFAS makers and users. No bill, no matter how important, deserves his signature if it includes this poison pill.

Mark Ruffalo is an acclaimed American actor and producer. A longtime environmental and political activist, he portrayed environmental attorney Rob Bilott in the 2019 legal thriller “Dark Waters.”