Firefighters may be at an increased risk of developing bladder cancer, according to a new study.

Researchers from the University of California, San Francisco, said in a news release that the risk of transitional cell carcinoma, a formal name for bladder cancer, is known to go up when people absorb carcinogens such as cigarette smoke.

This is because the kidneys clear the chemicals from the blood, and they end up stored in the bladder.

The team studied 1,286 active and retired firefighters for less than a year, looking for markers of bladder cancer before doing further examinations. Two of the retired firefighters were diagnosed with bladder cancer.

The researchers said that rate of cancer is much greater than what would be expected in a general population of men.