A group of 15 Massachusetts firefighters is suing equipment makers and distributors in federal court over the presence of so-called forever chemicals or PFAS (per- and polyfluoroalkyl substances) in their equipment.

The lawsuit, filed this week in U.S. District Court in Boston, claims that they were unaware that their protective clothing — also known as turnout gear — and Class B firefighting foams contained the flame-retardant chemicals, which are known to increase the risk of cancer and other diseases.

All of the firefighters, who retired from or are currently working for fire departments in Worcester, Boston, Brockton, Fall River and Norwood, have been diagnosed with or treated for cancer, according to the lawsuit. The group is suing for damages after discovering elevated levels of PFAS chemicals in their blood in December.

More than 20 manufacturers and distributors are named as defendants, including 3M, DuPont, Honeywell and Globe Manufacturing.

One of the firms representing the plaintiffs, California-based Pritzker Levine LLP, has filed similar lawsuits on behalf of over 100 plaintiffs in Massachusetts, New York and California, said Elizabeth Pritzker, one of the attorneys representing the firefighters.

“We think it’s especially egregious that firefighters have been treated this way for so long, and frankly lied to for so long about the potential causes of their cancers,” Pritzker said. “It’s time for us to do right by these first responders and make change and get them the remedies that they so deserve.”

Cancer is the leading cause of firefighter deaths, according to the International Association of Fire Fighters, the nation’s largest union representing firefighters.

In a statement, 3M stated it does not manufacture turnout gear worn by firefighters and that the company “will continue to vigorously defend our record of responsible use of PFAS and environmental stewardship in ongoing litigation, including these cases.”

Rich MacKinnon, president of The Professional Fire Fighters of Massachusetts, said the effects of PFAS have been an ongoing conversation for its members across the state, though his union is not involved in the suit. The union has been working on state legislation that would ban the chemicals.

“Our priority of our union has been dealing with the high risk and high rates of cancer among our members and how we address that,” MacKinnon said.

In Norwood, where two of the plaintiffs worked, cancers linked to PFAS have been a concern among firefighters, fire chief David Hayes told GBH News. For example, he has seen several cases of prostate cancer in his department. Now, there’s concern that those cases may actually be linked to PFAS exposure.

“It’s very disturbing to hear that the things you work with all your life suddenly cause cancer,” Hayes said. “These guys have just gone about their day, doing what they do, and inadvertently got exposed.”

While most departments have shifted away from PFAS-containing foams and use advanced gear-washing techniques, Hayes said another issue is what to do with old materials that departments may have. His department has several gallons of firefighting foam containing PFAS locked away, and he doesn’t have a way to dispose of it.

“Mostly everybody is focused on PFAS-free product right now,” Hayes said. “The question for each department individually is what to do to dispose with that foam that you have on hand.”

The Quincy-based National Fire Protection Association, which sets the performance standards for protective equipment, currently has a committee considering changes to testing and labeling of products containing PFOAs, a type of PFAS. The committee is expected to complete a first draft of its report this fall, which will be open for public comment.

“Our committees need to hear what the first responders think about the requirements,” Christian Dubay, vice president and chief engineer of the NFPA, said. “That’s how our standards get changed.”