The department says approximately 16 percent of its firefighters are women. Of that number, 15 percent of female firefighters between 40 and 50 years old have been diagnosed with breast cancer, which is six times the national average.
"Cancer is a concern for the San Francisco Fire Department as well as the fire service nationwide. But in San Francisco, we have seen and we do have numbers of elevated cancer rates for male and female firefighters," said Jeanine Nicholson, deputy chief of administration for the San Francisco Fire Department.
Over the last decade, more than 250 of the department's active and retired firefighters — both men and women — have died from various forms of cancer.
Nicholson is among the group of female firefighters who has been diagnosed with breast cancer. In 2012, she was diagnosed with an aggressive form of the disease called triple negative breast cancer.
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"Within two weeks, I had a double mastectomy and a port implanted in my chest," she said. "And a month later, I started what was the first of 16 rounds of chemotherapy."
Battalion Chief Anita Paratley was also diagnosed with breast cancer while serving the city of San Francisco.
"We didn't know how many the numbers were. But right after me, there seemed like one after another, younger women in their 40s," Paratley said of women being diagnosed.
But it's not just women seeing a spike in cancer — male firefighters have also been diagnosed with the disease.
San Francisco Fire Inspector Chris Gauer, who has been involved in fighting 186 fires, was diagnosed with vocal cord cancer about five years ago.
Because radiation didn't work to combat the disease, he had to undergo a full laryngectomy, meaning his voice box was removed.
"I never smoked — never was around, you know, tobacco smoke or anything like that. And my doctors also confirmed that it was definitely fire related," Gauer said.
The cause for the increase in cancers, including the breast cancer and other types that have spiked in firefighters, is believed to stem from the kinds of items burning inside homes.
Because of the increase in synthetic materials in homes, fire department researchers say firefighters are exposed to even more dangerous fumes.
"And we have a lot of flame retardants in furniture that are toxic and are toxic to you and your family as well as to firefighters," Nicholson said. "So you'll have these flame retardants in your bloodstream just as we do. We just have it in higher rates."
Firefighters are also more susceptible to chemicals that get on their skin. To combat this, firefighters are taking on more rigorous decontamination procedures.
A study conducted by the Women Firefighter's Biomonitoring Collaborative is hoping to produce more concrete answers for scientists and firefighters.
Until then, the threat of cancer is a fear consistently looming over the department.
"I always think of it as there's a cancer sniper out there in the fire service. And it's not when. It's not if. It's who's gonna be next? What woman in the San Francisco Fire Department is gonna get breast cancer next?" Nicholson said.