The measure was introduced Wednesday morning during a ceremony at City Hall to honor fallen firefighters.
Dozens of boots were placed on the steps of the rotunda to remember the 230 San Francisco firefighters who died from cancer in the last 14 years.
"It's is time to let San Franciscans and the world know that long after the fires are put out, firefighters are still fighting," union President Tom O'Connor said. "Fighting for their lives against cancer and other occupational illnesses."
The legislation would grant firefighters with cancer full disability and death benefits; unless it can be proven they did not get the disease because of their job.