LA fires exposed millions to toxic lead levels, study finds

Summarised from 2 outlets · Updated 28 Oct, 18:44 · Archive

About 7 million Los Angeles residents were exposed to airborne lead concentrations 80 times normal background levels during the 2025 fires.

During the peak of the 2025 Los Angeles fires, approximately 7 million residents were exposed in a 24-hour period to airborne lead concentrations that exceeded 80 times the normal background level, according to a study published Wednesday in the journal Science Advances.

Researchers from the California Institute of Technology compared the chemical composition of smoke from the Eaton Fire with that of a typical wildfire and found that the urban plume contained significantly higher levels of lead, arsenic and halogens, including chlorine and bromine. These toxic compounds were linked to burning vehicles, building materials and electronics.

Nga Lee 'Sally' Ng, an author of the study, said the key finding was that 'wildfire smoke is very different fundamentally from the urban smoke'. Using new technology to measure smoke composition, the researchers were able to identify 'the very detailed component of these particles that we are breathing'. Co-author Haroula Baliaka noted that understanding the different chemical compositions of smoke from urban versus wildland fires helps address a gap in research.

As wildfires grow larger, more intense and more frequent due to drier and warmer weather associated with climate change, researchers said monitoring and emergency response systems will need to adapt to the particular hazards posed by urban fires.

How it is being reported

• Smoke from LA fires exposed millions of people to high levels of toxic heavy metals, study saysDuring the peak of the 2025 Los Angeles fires, approximately 7 million residents were exposed to airborne lead concentrations over 24 hours that exceeded 80 times the normal background level, according to a new study published Wednesday in the journal Science Advances.Clickorlando · 28 Oct, 18:03
• Smoke from LA fires exposed millions of people to high levels of toxic heavy metals, study saysDuring the peak of the 2025 Los Angeles fires, approximately 7 million residents were exposed to airborne lead concentrations over 24 hours that exceeded 80 times the normal background level, according to a new study published Wednesday in the journal Science Advances.News4Jax · 28 Oct, 18:03

In this story: Los Angeles · California Institute of Technology · Eaton Fire · Nga Lee Ng · Haroula Baliaka

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