The facts
Haroula Baliaka and colleagues used hourly measurements at Pico Rivera, downwind of the fire, and compared the urban plume with the 2024 Airport fire's vegetation smoke. [1][2]
The urban plume contained over 50 times as much lead and three times as much arsenic as the wildfire comparison. At peak structural burning, estimated 24-hour lead concentrations were about 80 times normal non-fire background levels—a different comparison. [1][2]
The paper, 'Fire at the boundary: Airborne toxic metals from the 2025 Los Angeles urban firestorm', appeared in Science Advances, DOI 10.1126/sciadv.aei4455. [1]
Still unconfirmed
- The study does not establish individual doses or the long-term health effects of this short, intense exposure.
Sources
References support the numbered facts above. Source checks: 29 Oct 2026, 19:56 UTC.
Caltech's methods and results statement and AP's author and outside-expert interviews were checked. The full journal text did not load; no claim is made to have reviewed it.
- Chemical data collected from the Eaton fire plume help characterize urban fires
California Institute of Technology · Primary source · 28 Oct 2026
Institutional account of the peer-reviewed paper, measurements, comparison baselines and exposure estimate.
- Smoke from LA fires exposed millions of people to high levels of toxic metals, study finds
Associated Press via ABC News · Reporting · 28 Oct 2026
Independent reporting includes interviews with the researchers and experts outside the study.