Scientists race to detect ocean damage sparked by LA wildfires

As crews work to remove potentially hundreds of thousands of tons of hazardous materials from the Los Angeles wildfires, researchers and officials are trying to understand how the fires on land have impacted the sea.

The Palisades and Eaton fires scorched thousands of homes, businesses, cars and electronics, turning everyday items into hazardous ash made of pesticides, asbestos, plastics, lead, heavy metals and more.

Concerns arise as much of this debris could end up in the Pacific Ocean, potentially affecting marine life.

Fire debris and toxic ash could make the water unsafe, especially after rainfall, which can transport chemicals, trash and other hazards into the sea.

In the long term, there are worries about the impact of charred urban contaminants on the food supply.

The recent atmospheric river and mudslides have intensified these concerns, increasing the risk of runoff carrying contaminants toward the ocean. Runoff can contain nitrogen, phosphate, heavy metals and pollutants from burned materials.

Mudslides and debris flow in the Palisades Fire burn zone can also dump hazardous waste into the ocean. After fires, the soil becomes less able to absorb rainfall, raising the risks of further runoff.

Local officials have set up concrete barriers, sandbags and other measures to prevent debris from reaching beaches.

State and federal agencies are also conducting tests to monitor ocean water for toxins, metals and chemicals, including microplastics and banned substances like PCBs, which pose serious health risks.

Recent water tests have not raised immediate health concerns, and one beach closure was downgraded to an advisory. However, scientists are continuing to study the extent of the contamination and how long the effects will last.

Forest fires can sometimes deposit beneficial nutrients into the ocean, but the toxic ash from urban fires could have severe consequences for marine organisms.

Researchers are studying how fire debris affects the ecosystem and the food chain, taking tissue samples from fish to check for contaminants.

It will take time to fully understand the impact of these urban fires on the environment and food supply.

(Cover: People walk on the beach after debris from the Los Angeles fires are washed ashore in Santa Monica, California, February 15, 2025. /VCG)