Lab Matters Spring 2026 | Seite 23

ENVIRONMENTAL HEALTH

By Jeff Wagner, PhD, chief, Environmental Laboratory Branch, California Department of Public Health Center for Laboratory Sciences and Emily Potter, DrPH, fellow, Environmental Health materials cleanup. This collaboration underscored the critical connection between scientific analysis, laboratory capacity and public health guidance, particularly in the immediate aftermath of the fires.

Figure 1. Interagency coordination during the LA fires recovery.

Major United States disasters in the first half of 2025 marked the costliest six-month period on record, causing more than $ 100 billion in damages. Among these events were the devastating wildfires that swept through Los Angeles, California, in early January 2025. Impacts included fatalities from both direct firerelated losses and indirect impacts on the region’ s health and emergency response systems.

The role of interagency environmental testing during one of the worst disasters in the state’ s history was paramount. Coordinated measurements demonstrated an optimized model for public health laboratory response. In the immediate post-fire response, standardized testing from various agencies enabled rapid assessment of potential exposure risks, guided emergency cleanup and informed protective public communications. Exploratory testing helped increase understanding of what substances were left after the fire to inform future planning.

A Multi-hazard Environment

The Los Angeles wildfires created overlapping risks, combining fire devastation with potential environmental and public health threats across air, water, soil and indoor dust. The fires released soot and burned building materials, degraded air quality with increased airborne particulate matter( PM) and metals, and potentially impacted soil, drinking and recreational waters with fire-related runoff.

The defining challenge was to rapidly prioritize and test diverse, time-sensitive samples under pressure. As such, the California response exemplified adaptive, high-impact public health response.

Coordinated Laboratory Response

Several task forces were formed by local, state and federal partners to assess these risks. Environmental and public health teams provided technical expertise on a range of measurements, including air, soil and water quality, vector control, worker safety, toxicology and hazardous

California agencies( Figure 1) conducted analysis of air samples, ash and indoor dust to assess chemical risks and unique fire signatures. This included standardized testing to monitor for PM and airborne metals by the South Coast Air Quality Management District, the California Air Resources Board and the US Army Corp of Engineers, as well as exploratory methods to better understand potential additional pollutants conducted by the California Department of Public Health Environmental Health Laboratory. Some smoke and ash chemical risks can be determined by comparing to established standards like outdoor

What is PM 2. 5?

PM 2. 5

( fine particulate matter) refers to airborne particles smaller than 2.5 micrometers in diameter— about 30 times thinner than a human hair. Wildfire smoke is a major source of PM 2. 5

, which can penetrate deep into the lungs and enter the bloodstream, increasing the risk of respiratory and cardiovascular health effects, especially for sensitive populations.

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