Photo: Randy Millis

New research has confirmed what firefighters have long suspected — exposure to flames and smoke leaves them with elevated levels of toxic chemicals in their bodies.

In what may be the first before-and-after study of the occupation, a University of Ottawa researcher has found battling blazes leaves firefighters with significantly higher levels of chemicals that can cause both cancer and genetic damage.

"We looked at what was there before and then after the fire," said Jules Blais, author of a paper in Environmental Science and Technology. "This is really something that hasn't been done."

Blais worked with a group of firefighters in Ottawa, taking urine samples and skin wipes at the start of their shifts and after they'd been out on a call.

Both samples after a fire showed high levels of polycyclic aromatic hydrocarbons — so-called PAHs — that are created by burning plastic and are known to cause damage and genetic mutations within cells. Such chemicals are commonly produced in all kinds of fires.

Blais found PAH levels were typically three to five times higher after a fire. For some firefighters, the increase was 60 times.

The results were compared with those of colleagues who hadn't left the office as well as with overall Canadian averages.

As well, firefighters are regularly re-exposed to the same chemicals.

Tests taken from lung fluid samples didn't show chemical markers for contaminants. However, the skin and urine samples matched up, suggesting the toxins are being absorbed through the skin.

"This is research that can lead to very short-term gains," said Blais. "If we can learn to reduce these exposures, we can have a very immediate impact on health. Take a shower, is part of it."