Air quality monitoring in the Eaton and Palisades fire areas in March and April found elevated levels of chromium-6 (also known as hexavalent chromium, or “hex chrome”) in the air. The chromium was mostly in the form of very small particles, called nanoparticles, with size less than 56 nm (nanometers). The findings were published by LA Fire HEALTH researchers at UC Davis and UCLA and were released as a preprint yesterday.
More testing is needed to determine how much chromium-6 remains in the air, soil, and dust in the fire-impacted zones now that debris cleanup has mostly been completed. We have let all relevant government agencies know about this finding.
We created this data brief to try to help you understand these findings and their impact.
In the meantime, simple precautions are warranted to help avoid exposure to this potentially carcinogenic form of chromium:
- Use air cleaners or purifiers with HEPA filters inside homes, offices, community spaces, and classrooms in or near the burn zones.
- Upgrade HVAC filters to MERV 13 or higher rated filters.
- Use HEPA vacuums to clean floors and upholstery.
- Remove shoes before entering homes and wipe pets’ paws to avoid tracking dust into homes.
- Wear N95 or KN95 masks while cleaning to avoid inhaling particles that may be stirred up during cleaning and debris removal activities.
What You Should Know
- Recent analysis of airborne particles collected in the outdoor air around the debris cleanup zones for the Eaton and Palisades fires during March and April 2025 detected the presence of airborne metals, including chromium-6.
- Chromium-6, also called hexavalent chromium, is a form of chromium that is more toxic than the usual type of chromium detected in air, soil, and dust, called chromium-3.
- The measured chromium-6 levels were below limits set for workers, but above screening levels for workers and the general public. Screening levels are used to determine when additional investigation is warranted.
- Read more about the findings, why this matters, and answers to key questions about Chromium-6 in the new Data Brief below:
What is a preprint?
A preprint is a preliminary version of a manuscript (research paper) that has not completed peer review at a journal. Typically, when a scientific paper is published, a group of editors and other scientists review the data to verify its accuracy and the make sure the methods used are scientifically sound. Preprints are a way of sharing important data with the community as quickly as possible, while the scientific review process is still underway.
9 responses to “New LA Fire HEALTH Data Brief: Chromium-6 detected in air near LA burn zones”
I have standing home with burned down houses all around me as far as the eye can see. Windows were open. We’re in our 70’s. Our daughter is pregnant. We haven’t moved back but planning too. My question, is this a continuing testing in the palisades? Is it expected the levels in the air will continue to be high or get lower? Are the findings going officially to epa, who didn’t test? Did finding go to Ca insurance commissioner, since there’s such low priority for standing homes? Where else is this been published ie. LA Times, NY Times,?
I have standing home with burned down houses all around me as far as the eye can see. Windows were open. We’re in our 70’s. Our daughter is pregnant. We haven’t moved back but planning too. My question, is this a continuing testing in the palisades? Is it expected the levels in the air will continue to be high or get lower?
For people living in homes near the burn, what does this discovery mean? How long will this chromium be in the air? Does it settle, like lead, into the soil? How much of it will expose a child, dog or adult to health issues, and what are the health outcomes? Can a person be checked for chromium? Can it be eradicated from a persons blood?
Will similar tests for these exact compounds be continued month after month so that comparisons and/or improvements could be reported?
I live 4/10 of a burning structure on a street that was not burned in Altadena. I am wondering how much danger I am in in being exposed. I am just east of Casitas which also did not burn. Thank you.
4/10 of a mile…
I had wondered about the cause of experiencing headache each time I spent a little time (may be 20-30 min) at my empty lot after January 7 fire. Both before the debris was removed (more severe headaches then) and after debris removal (less severe). They went away after resting.
[…] Last week, iO Wright from PostFire LA, in partnership with EFRU and Resilient Palisades, hosted a live Q&A with LA Fire HEALTH Study experts to answer your questions about chromium-6 (Cr6 or hexavalent chromium). The video came together in response to the preliminary findings about Cr6 in the air that were released by the LA Fire HEALTH Study on August 2…025. […]
[…] August, new research found that Cr6 levels during March, April, and May were elevated in the fire-affected areas of the […]