Before-and-after study by university shows firefighters absorb toxins

OTTAWA — 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.

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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.

The study also looked at the potential for chemicals in the urine to cause genetic damage. That average was also about four times higher after an action-packed shift.

“There was evidence that during the on-shift fire suppression event, there was exposure to these substances,” Blais said.

Although PAHs generally only last a few days in the body, Blais said that’s time enough.

“It’s when the body is in the process of trying to take these things, that’s actually when the damage takes place.”

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

“The lifetime exposures can be high.”

Blais was also able to suggest how firefighters are being exposed.

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, whose research was partly funded by the Ontario Ministry of Labour. “If we can learn to reduce these exposures, we can have a very immediate impact on health.

“Take a shower, is part of it.”

Previous long-term studies of firefighters have shown they are prone to some diseases.

“They have a heightened risk from certain cancers, for example,” said Blais.

— Follow @row1960 on Twitter.

Bob Weber, The Canadian Press