Concerns growing over CA wildfires, toxic metals: Here's what to know

PALO ALTO, Calif. (KGO) -- New information is emerging about the long term threat from some wildfires in California. Researchers at Stanford say it's a toxic mix of dangerous metals and the air we breathe.

As a researcher with the Stanford Doerr School of Sustainability, Scott Fendorf, Ph.D., is no stranger to wildfires and the toxic threat they can create.

He and his team uncovered an effect of superheated fires, burning so hot they can transform a naturally occurring element in the soil called chromium, into a toxic version known as chromium 6.

But now he says studies of this year's massive fires in Southern California, are confirming a broader, laundry list of dangerous metals. With the type and concentration changing as the flames roar through different areas.

"The Eaton Fire started as a true wildfire. And then it moved through the wildland, the wildland urban interface and then ultimately into the actual urban center. And across that, you actually see a different set of contaminants," says Prof. Fendorf.

He explains the threat shifts to elements like lead as the flames reach populated areas, along with another extremely dangerous pollutant called Beryllium, literally melted out of commercial metals by the heat.

"So there's a number of different elements that have been showing up. So, I think lead is the one that's probably the highest on the list in terms of concentration and toxicity. And so I would say largely it's the biggest risk driver. The beryllium story that's just emerging is also one to be thinking about," he adds.

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And researchers say those metals are not only being found on the ground, but also in tiny particulate matter carried for miles by the smoke. Dr. Sharon Chinthrajah, M.D., is a lung specialist at Stanford, who recently co-authored a study on the effects of critical smoke exposure on immune cells.

"And we're able to show that, these substances that are in wildfire smoke and different parts of pollution can actually change the genetic expression in immune cells that lead to activation of immune cells and importantly, that there are some effects that are seen with more and more exposure." she says.

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While the long-term effects will need further study, she says several compounds are also known cancer risks. And both researchers believe the new data could help drive an even more aggressive public health response and warning system in future wildfires.

"In communities to make sure that not just vulnerable populations like children, pregnant women, elderly people, but all, all people, have a safe place. So, I'm talking about filters in the home, filters in the school, really to clean the air," says Dr. Chinthrajah.

"You can look at the air quality index, and that gives you the total particle counts. But it doesn't tell you if those particles might have led in them, if they might have developed chromium. And those are the parts that were just starting to emerge on and including the long-distance transport of those particles," adds prof. Fendorf.

A call to action, driven by an emerging understanding of the threat wildfires pose to the air we breathe.