Since fires erupted across Los Angeles County in January, Ashley Oelsen has spent several hours each day collecting ash and soot from the beach outside of her Santa Monica apartment. Oelsen, a conservation biologist who sits on Santa Monica’s Commission on Sustainability, Environmental Justice and the Environment, worries about the dark-colored, pungent piles of burned debris that continue to mix with the sand, plant life and ocean water.
“I’m concerned about the way it will affect us long term,” she said. “It’s endless amounts of worry about the impact of the contaminants.”
Oelsen said she has spent about $8,000 of her own money shipping her beach samples to laboratories to test for toxic materials.
More than 16,200 structures burned in the Palisades and Eaton wildfires, raising concerns about toxic ash. Many of the incinerated homes and businesses contained various heavy metals, such as copper, lead, zinc and aluminum. Some older homes were constructed with asbestos or lead paint. Newer devices like electric cars or solar panels held lithium batteries. Exposure to these materials presents such significant health risks as cardiovascular disease and reduced lung function.
Researchers at the University of California, Santa Barbara, found that wildfire ash can fertilize algae, which can lead to a depletion of oxygen in the water. This kills the algae, as well as fish — and species that rely on both for sustenance.
Craig Nelson, oceanography professor at the University of Hawaii at Mānoa, heard similar concerns from residents following the Lahaina wildfires in August of 2023.
“Our main concern was things coming from melted plastic, things coming from burned wood and burned structural material that made [their] way into the water,” he said. “We didn’t find anything. We’re pleased but not terribly surprised.”
Nelson said not much is known about pyrogenic material — the substances generated during a fire.
“What we know is that when you heat up any molecule, it often changes,” he said. “When you’re measuring them, you have to know exactly what it looks like. There’s thousands of compounds that you could be looking for, some of which fall into classes that we know about and some we just don’t know. Pyrogenic materials are not high on the list of things that are regulated or studied.”
This week, the Trump administration announced plans to eliminate the scientific research arm of the Environmental Protection Agency. Under the proposal, as many as 1,155 chemists, biologists, toxicologists and other scientists, responsible for the independent research that undergirds virtually all of that agency’s environmental policies, would be fired, making future guidance on pyrogenic materials unlikely.
Nelson said that his team collected and submitted a dozen fish for analysis at the National Oceanic and Atmospheric Administration, but following recent cuts to the agency’s workforce and facility closures, he is doubtful they will get their data back — let alone analyzed.
The Los Angeles County Department of Public Health recently issued an advisory for local beaches in the wake of the fires that suggests visitors can “recreate on the sand,” but should stay out of the water and avoid debris along an eight-mile stretch of shoreline from Santa Monica State Beach to Las Flores State Beach.
On March 12, Los Angeles County Public Works released findings from beach sediment tests, which found the samples did not contain any substances that would be classified as hazardous waste. One sample from both the Santa Monica Channel and Topanga Creek outlet was taken in early February.
The sediment was tested for materials like asbestos, heavy metals, dioxins, pesticides and petroleum hydrocarbons. The county reported that minor traces of these were detected that did not exceed safety thresholds.
These thresholds themselves are changed frequently. In 2024, the Biden-Harris administration lowered the threshold for the level of lead in dust that EPA considers hazardous. However, there is no safe level for lead exposure.
Jane Williams, the executive director of California Communities Against Toxics, shares Oelsen’s alarm over potential contaminants that may be overlooked.
“My biggest concerns [about] the exposures that are occurring is that we are in the process of repeating the post-9/11 exposure pattern,” she said. “We started seeing health issues in cleanup workers within a year of the 9/11 cleanup, and within a few years those workers started to die.”
Since the attacks at the World Trade Center on September 11, 2001, nearly 17,000 first responders and others who were in the area have been diagnosed with cancer. More than 6,000 deaths have been attributed to 9/11 illnesses. Williams fears similar phenomena in the wake of the Los Angeles fires.
“What’s happening is what I call the disaster after the disaster,” she said.
Ashley Oelsen is awaiting the results of her tests, but wants people to lean on the side of caution. “We don’t know the long-term effects,” she said. “We don’t have the data. We don’t have the information.”
