(CBS) — They put their lives on the line every day to save others, and many of them are paying a heavy price.

A new study reveals a surprising link between firefighters and cancer.

Nearly 15,000 of them were included in this research, and the results could lead to some big changes in the way firefighters do their jobs.

CBS 2’s Chris Martinez reports.

It’s a phone call Andy Dina will never forget, with these three words:

“You have cancer.”

The veteran firefighter, a lieutenant with the Naperville Fire Department, was diagnosed with prostate cancer at 46 years old.

Thousands of first-responders have faced that fight. A newly released study looked at 30,000 firefighters from three departments: Chicago, San Francisco and Philadelphia over nearly 60 years.

The conclusion, according to Tom Ryan, president of the Chicago Firefighters Union Local 2: “Our cancer levels will be higher than the average person.”

Chicago firefighters are two and half times more likely to develop mesothelioma from exposure to asbestos. They also have a higher rate of digestive and respiratory cancers and develop kidney, bladder and prostate cancers far younger than the average age of 65.

Matt Montague was diagnosed at 34 with acute leukemia.

The cause may be chemicals released when modern-day materials burn and are breathed in.

They may also be absorbed through the skin, even away from the fire.

Bob Hoff, a Chicago firefighter for 35 years, is now in Carol Stream. He showed his department’s gear-storage room.

A companion study recommends keeping gear outside the truck after fighting a fire and then storing it in its own ventilated room at the station.

Firefighters should also shower immediately after.

The potential new guidelines come too late for many.

Robin Youngberg’s husband, Vic, was a career firefighter.

He lost his battle at just 56 years old.

“He had metastatic lung cancer that settled into the spine,” his widow says. “We didn’t have control over when that day was, but he went out with no regrets.”

More than 30 types of cancer were examined in this research and later this year. A second phase of the study will be released that should give a better idea of how exposures to certain chemicals might lead to specific cancers.