Living near wildfires ups cancer risk

Residents stand on their roof to watch a wildfire burn near their home September 1, 2009 in Glendale, California. (Credit: Justin Sullivan/Getty Images)

People exposed to wildfires have a higher incidence of lung cancer and brain tumors, a new study finds.

Researchers tracked over two million Canadians over a period of 20 years. They say the study is the first to examine how proximity to forest fires may influence cancer risk.

Wildfires tend to happen in the same locations each year, but we know very little about the long-term health effects of these events,” says Scott Weichenthal, an associate professor in the epidemiology, biostatistics, and occupational health department at McGill University. “Our study shows that living in close proximity to wildfires may increase the risk of certain cancers.”

Published in The Lancet Planetary Health, the study shows that people living within 50-kilometers (about 31 miles) of wildfires over the past 10 years had a 10% higher incidence of brain tumors and 4.9% higher incidence of lung cancer, compared to people living further away.

With the changing climate, wildfires are predicted to become more prevalent, severe, and longer in duration in the future—and they are increasingly recognized as a global health problem.

“Many of the pollutants emitted by wildfires are known human carcinogens, suggesting that exposure could increase cancer risk in humans,” says lead author Jill Korsiak, a PhD student in Weichenthal’s lab.

Wildfires typically occur in similar regions each year, and as a result, people living in nearby communities might be exposed to carcinogenic wildfire pollutants on a chronic basis, the researchers say.

In addition to effects on air quality, wildfires also pollute aquatic, soil, and indoor environments. While some pollutants return to normal concentrations shortly after the fire has stopped burning, other chemicals might persist in the environment for long periods of time, including heavy metals and hydrocarbons.

“Exposure to harmful environmental pollutants might continue beyond the period of active burning through several routes of exposure,” Weichenthal says.

Still, more research is necessary to understand the complex mixture of environmental pollutants released during wildfires, the researchers say. They also note that further work is needed to develop more long-term estimates of the chronic health effects of wildfires.

Source: McGill University