Caltech Research Buttresses New Law to Address Lead Contamination after Wildfires

Gov. Newsom signs the wildfire-related bills. Image: Governor’s office.

by Andrew Moseman

This month, in Altadena, California Governor Gavin Newsom signed a package of fire-related bills connected to the January 2025 fires in which thousands of Los Angeles County residents, including many members of the Caltech community, lost their homes. One of those bills, AB 1642, was informed by research out of the laboratory of Francois Tissot, Caltech professor of geochemistry and Heritage Medical Research Institute Investigator. Authored by Pasadena Assembly Member John Harabedian, the bill establishes first-in-the-nation standards to measure and address contamination from lead and other toxic materials left behind in homes after a wildfire.

In the aftermath of the Eaton fire, Tissot and his lab members pivoted much of their research to measuring and analyzing the dangerous substances released during the disaster, sharing their findings with the public. Tissot worked closely with Harabedian’s office and organizations, including Eaton Fire Residents United, to shape the legislation and was present for the signing ceremony.

“The standing homes of the Eaton fire were a curse in disguise.” Tissot said. “Spared by the flames, the data show that these homes were pervasively contaminated with asbestos, lead, and other toxic heavy metals released by the fire. In the absence of mandatory testing and scientific standards to remediate properties, many families were forced to return to still-contaminated homes, putting their health at risk. As a victim of the fire and an isotope geochemist who has studied this contamination firsthand, I am thankful that AB 1642 will help protect other communities by creating scientific standards and guidance for safe re-occupancy for wildfire survivors.”

Read more about AB 1642 and its companion legislation to “strengthen California’s long-term wildfire recovery system.