Tuesday, June 2, 2026

Study Finds Carcinogenic Chromium-6 Near Eaton Fire Cleanup Zone

CITY NEWS SERVICE and STAFF REPORTS

Cell phone images of the first moments after the Eaton Fire ignited on Tuesday, Jan. 7, 2025, on the mountainside opposite Midwick Drive’s terminus at N. Altadena Drive in Altadena. [Jennifer Errico]

The study, published in the journal Nature Communications Earth & Environment, found elevated concentrations of chromium-6 nanoparticles in the air around wildfire cleanup zones approximately two months after the fires were extinguished.

Researchers said the particles may have traveled six to nine miles downwind, potentially affecting communities far beyond the burn areas.

Chromium-6 is a highly toxic, carcinogenic form of the metallic element chromium. Often produced by industrial processes like metal plating and leather tanning, it also leaches into water from natural rock deposits. It poses severe cancer and respiratory risks.

“Hexavalent chromium, or chromium-6, is a toxic metal and carcinogen that can impact the lungs and is associated with asthma, bronchitis, and lung cancer,” Michael Jerrett, a professor in UCLA’s Department of Environmental Health Sciences and a co-author of the study, said in a statement. “It shows that well after the wildfires were extinguished, nanoparticles, which are so small they can enter the circulatory system very quickly, were in the air around the burn zones.”

The Eaton Fire killed 19 people and destroyed nearly 10,000 buildings, scorching 14,000 acres.

Jerrett said the nanoparticles may have exposed as many as 3.3 million people to levels hundreds of times higher than those typically found in Los Angeles air.

Researchers reported average chromium-6 concentrations of 13.7 nanograms per cubic meter. While below federal workplace exposure limits, the levels exceeded U.S. Environmental Protection Agency screening thresholds for indoor air, according to the study.

Yifang Zhu, another UCLA co-author, said chromium-6 concentrations declined over time and returned to background levels roughly eight months after the fires as the substance converted into the less toxic chromium-3 form.

The researchers said modeling suggests airborne particles may have reached communities including Beverly Hills, West Hollywood and portions of the San Fernando Valley. They recommended continued monitoring around wildfire cleanup zones and advised nearby residents to use indoor air filtration and limit outdoor exercise until conditions return to normal.