When relatives say Tom Dickinson gave his life to firefighting, they don’t just mean 40 years in the Minneapolis Fire Department, including 15 as chief.

They believe the stomach cancer that killed him two years ago, at age 78, resulted in part from the chemicals he breathed in during fires. “His job, it contributed to taking his life,” said son Mark Dickinson, also a St. Paul fire captain.

Now the younger Dickinson wants to cut the risks for other firefighters by supporting Minnesota legislation to ban flame retardant chemicals suspected of increasing cancer risks.

“We have an inherently dangerous job and cannot completely eliminate all the dangers we are exposed to,” Dickinson said in Senate committee testimony this month. “However, we can reduce the dose we are exposed to.”

Flame retardants give people only 3 additional seconds on average to escape from fires, but produce twice the smoke and 40 times the soot as fires involving untreated furniture, he said.

Legislation would place a cap on the application of 10 fire retardant chemicals to furniture, mattresses and children’s clothes. Business lobbyists have raised concerns about the number of chemicals in the ban, although some are already being phased out of production.

Federal researchers last month reported elevated rates of lung cancer and leukemia deaths among firefighters in Chicago, Philadelphia and San Francisco.

Environmental toxicologist Susan Shaw has tested blood levels in Maine firefighters after fires and found elevated levels of flame retardant chemicals.

Missing, though, is a causal link — proof that elevated chemicals actually cause more deaths. The National Institute of Occupational Safety and Health will be studying that question soon, a spokeswoman said.

Also unclear is the risk facing today’s firefighters compared with the old guard. The older Dickinson used to remain in smoky buildings until he was dizzy — in an era before respirators. Still, inhalation is only one method of exposure. High heat can increase skin absorption of these chemicals, Mark Dickinson said. “Firefighters become literally sponges,” he said.