Wildfires may release cancer-causing chromium 6, study reveals

A new study from Stanford University suggests wildfires could lead to chromium 6, a cancer-causing agent, being released in the air. 

Researchers recently released their findings in Nature Communications sayind that wildfires can transform benign metals in soil and plants into toxic particles. 

The team said they found chromium-rich soils at wildfire sites compared to adjacent unburden sites. 

"Our study suggests far more attention should be paid to wildfire-modified chromium, and we presume additional metals as well, to more thoroughly characterize the overall threats wildfires pose to human health," lead study author Alandra Lopez said in a news release

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Scientists add that in nature, chromium is usually in the form of chromium 3, which is an essential elemental in the human body used to breakdown glucose. 

However, chromium 6 is usually formed in industrial processes and can become a cancer risk if inhaled or ingested, such as in contaminated drinking water. 

It's believed wildfires can transform chromium 3 into chromium 6 in surface soils. 

Scientists said wildfire smoke is known to already carry "dangerous air pollutants including gases, organic aerosols, and fine particulate matter, which can trigger asthma attacks, heart attacks, and early death."

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But they said less attention has been paid to the surrounding soil, and with wildfires expected to increase in the future, they believe the research needs to be better understood. 


In this photo taken on October 10, 2023, a man looks at a forest fire as it approaches houses in Ogan Ilir, South Sumatra. (Photo by Al ZULKIFLI / AFP) (Photo by AL ZULKIFLI/AFP via Getty Images)

"In the complex mixture of gasses and particles that wildfires spew out as smoke and leave behind as dust, heavy metals such as chromium have largely been overlooked," senior study author Scott Fendorf added.

Scientists worry first responders and nearby residents of a wildfire could be exposed to chromium 6. They say the risk usually decreases after rainfall.

They recommend potentially affected people to wear an N95 mask when visiting a burn site.

This story was reported from Los Angeles.