Research Evaluated Ocean Water Quality After 2025 Fires

Scientists studied chemical contaminants in Los Angeles ocean waters following urban fires in early 2025.

Updated on Sept. 22, 2026 in Environmental

A weathered concrete drainage pipe meets the Pacific ocean shoreline, highlighting the connection between urban coastal infrastructure and marine environments. — The CLEAN Waters program analyzed contaminant levels in Los Angeles coastal waters following urban fires in Altadena and Pacific Palisades earlier this year. AI Illustration. Upload story photo >

Live Poll

Do you feel confident that your local coastal waters are safe for swimming after recent fires?

Following urban fires in Altadena and the Pacific Palisades in January 2025, research organizations investigated the resulting impact on local ocean water quality. The CLEAN Waters program analyzed the presence of heavy metals and other toxins that leached into the sea.

Why it matters

The study provides insight into how fire-related pollutants disperse in marine environments via wind and currents. It highlights the current lack of official state guidelines for recreational ocean contact in the wake of urban fires.

Researchers analyzed 100 different chemicals for risk screening using an Environmental Protection Agency tool. Data collected between January and May 2025 indicated that most chemical levels remained below established exposure risk thresholds.

The players

Heal the Bay

This non-profit environmental organization focuses on protecting the coastline and ocean waters in Southern California through advocacy and research.

CLEAN Waters

This research program was launched in 2025 specifically to evaluate the environmental impacts of urban fires on local water systems.

Los Angeles County Department of Public Health

This local government agency is responsible for protecting public health and issuing safety advisories for community recreational areas.

The details

While researchers observed a rise in contaminants immediately after the January 2025 fires, ocean currents and winds helped these pollutants disperse. Heal the Bay continues to advocate for California to implement formal safety standards for recreational ocean water.

Urban fires occurred in Altadena and the Pacific Palisades throughout January 2025.
Water quality data was collected between Jan. 27 and May 1, 2025.
The Los Angeles County Department of Public Health lifted its ocean contact advisory in April 2025.
Full CLEAN Waters research data is expected to be released in May 2026.

Deeper Dive

This study highlights a gap in California's lack of recreational ocean water chemical safety standards, which currently do not exist to regulate chemical exposure. The findings represent a departure from established bacterial safety protocols, suggesting a need for expanded environmental monitoring frameworks.

The study confirms that while pollutants entered the water, levels generally remained below exposure risk thresholds for the public. Residents can look for future state-level policy updates that may change how authorities manage ocean access during and after local fire events.

The takeaway

While the 2025 fires caused immediate concern regarding water safety, current data suggests that natural ocean processes effectively mitigated high-level chemical risks. This study emphasizes the importance of future standardized monitoring to better protect swimmers and coastal visitors.