It seems like a straightforward question: Do the tons of toxic material the Los Angeles County fires sent spewing into the ocean pose an ongoing threat to human health?

For nearly five months, public agencies, advocacy groups and scientists have analyzed samples of seawater and sand in an attempt to determine whether January’s catastrophe has made it less safe to swim, surf or sunbathe at the region’s famous beaches.

Their collective results point to two broad truths.

The first is that neither government agencies nor privately funded groups have found levels of fire-related contamination in sand or ocean water likely to pose health risks to beachgoers. While visible fire debris still occasionally washes up on shore and should be avoided, public health officials and advocates say, there is little evidence of fire-related toxins high enough to sicken visitors through casual recreational exposure.

The second is that the unprecedented amount of ecological damage January’s firestorms caused simply dwarfs the tools we have available to measure beach pollution.

The seawater safety testing that informs the county’s beach water quality advisories is designed to look for hazards posed by sewage, not fire debris.

State and federal regulators have clear guidelines on the maximum amount of heavy metals and chemicals that can be in our drinking water before it is deemed unsafe, but no similar standards for how much of this stuff it is safe to be exposed to when swimming.

This lack of preexisting health guidelines has made it hard for public health officials to describe the situation at the coast in simple, declarative terms. That, in turn, has frustrated a public that just wants to know if it’s safe to get back on a surfboard.

“There are no human health standards for recreating in water or on sand that has been contaminated, potentially, by these pollutants … and so there’s no straightforward way to test for contaminants and then [say] this exceeds the risk threshold, or it doesn’t,” said Tracy Quinn, president of the environmental nonprofit Heal the Bay. “And that has presented a lot of challenges.”

The Palisades and Eaton fires incinerated more than 40,000 acres and countless tons of plastics, electronics, building materials, batteries and other potentially hazardous materials. Because of the region’s geography, much of that toxic ash and residue eventually flushed into the ocean.

County health officials closed several miles of coastline entirely in January and February, citing spiking levels of bacteria caused by destroyed sewage systems and dangerous amounts of hazardous debris clogging up the shore.

In the meantime, the Los Angeles Regional Water Quality Control Board began collecting samples of ocean water to assess contaminant levels.

The board soon had reams of public data for beaches from Las Flores Creek in Malibu to Dockweiler Beach in Playa del Rey, showing results for dozens of different contaminants, including heavy metals, polychlorinated biphenol and polycyclic aromatic hydrocarbons.

But, again, there are no established regulations for how much of these contaminants a surfer or swimmer can be safely exposed to. There also isn’t much historical data with which to compare the current amounts of pollutants such as plasticizers, fire retardants and other modern chemicals to pre-fire conditions.

As a result, county health officials struggled to translate their findings into recommendations the public could use.

“This is not business as usual with ocean water testing,” said Dr. Nichole Quick, chief medical advisor with the L.A. County Department of Public Health.

County health officials spent hours plugging the numbers into a publicly available Environmental Protection Agency tool that helps evaluate safe environmental exposure levels to various substances. They also invited experts from other agencies to weigh in.

No matter how they ran the numbers, they didn’t see evidence that the levels of contaminants present in January and February would threaten human health.

Heal the Bay tested seawater around the same time. The group found enough lead and other heavy metals in some samples to potentially build up over time in the tissue of marine life, but not high enough to sicken a human swimming in those waters.

The county now has an online dashboard for post-fire environmental data that includes ocean water testing.
But by the time it went live this spring, many members of the public were already frustrated by the lack of clear-cut answers and the confusing pile of data online, said Eugenia Ermacora, Los Angeles chapter manager for the Surfrider Foundation.

“It creates this anxiety,” she said. “Everybody wants an answer right now: Is it safe? Me too! I’m a surfer. My fins are drying. But we’re trying to be patient at the same time.”

L.A.’s coastal ecosystem is now the subject of a massive real-life science experiment. As in all sweeping studies, it will be a while before clear answers emerge. In the meantime, advocates are hopeful that L.A.’s experience now will help communities respond to disasters in the future.

“This is not the last time we’re going to see an urban megafire in a coastal city. It may not be the last time we see an urban megafire in Los Angeles, and we need to be better prepared,” Quinn of Heal the Bay said. “My hope is that we take the information that we’re learning here and we create protocols and standards for what to do next time.”