The manufacturers of “forever chemicals” used in products like nonstick pans and waterproof clothing knew about the dangers their materials posed more than forty years before the general public, according to previously secret industry documents. By following the same playbook as Big Tobacco, including suppression of their own research, the companies successfully stymied regulation for decades while the cancer-causing chemicals became ubiquitous in the water, air, and soil.

Major manufacturers are already spending billions to settle lawsuits and millions fighting federal regulations, including landmark environmental rules proposed this spring. The revealing industry documents, analyzed in a new study from researchers at the University of California San Francisco (UCSF), could bolster efforts to hold the companies accountable for widespread contamination from chemicals that take hundreds of years to break down. The manufacturer 3M is reportedly preparing to pay $10 billion to settle claims that it polluted thousands of public water systems, but the cost of cleaning up the chemicals in drinking water nationwide will likely top $400 billion.

Introduced into a variety of consumer goods beginning in the 1950s, per- and polyfluoroalkyl compounds, or PFAS, are linked to decreased fertility, developmental delays, and several types of cancer.