Mysterious California Landfill Fire Raises Major Health Fears

Deep within the Chiquita Canyon Landfill site near Santa Clarita, to the north of Los Angeles, a fire has been burning, releasing noxious gases and vapors that have left local residents smelling foul odors and led to a multiagency task force to be formed to address the issue.

Hazardous chemicals such as benzene—a carcinogen—and dimethyl sulfide, which is considered acutely toxic, have been detected being emitted at the landfill site, along with a host of other compounds, as discarded substances in the landfill mix and react with one another, raising concerns about the impact to locals' health that the emissions could have if not addressed soon.

"If the concentrations are above the odor threshold for the sulfide compounds, the odor thresholds are often lower than the health-based exposure benchmarks—so it doesn't necessarily mean that there's an acute health risk associated with that," Marc Glass, principal environmental consultant at Downstream Strategies, who has advised state and federal governments on contamination, told Newsweek.

"Some other compounds—benzene being one of them—there are effects even at or below the odor thresholds. So if you can smell it, it's probably not good."

However, he cautioned that he had not seen the monitoring data from around the Chiquita Canyon site and so could not make a concrete evaluation of the risks the emissions pose.

Authorities say that air quality monitoring has been established around the site and in the nearby community, and currently there was no evidence of contamination of nearby waterways. The operator of the landfill site has taken steps to control the emissions.

"Landfills are all over and have a lot of hazardous substances in them," Glass said. "All kinds of chemicals—consumer containerized products, including paints, and all kinds of solvents and things like that—that consumers use and discard make their way into landfill."

While they are usually individually in small amounts, he added, they can add up to large amounts of hazardous substances in landfills "because it would be difficult for the public to deal with managing hazardous waste streams" without disposing of them in the trash.

Michael Brogan, a spokesperson for the Environmental Protection Agency (EPA) in the region, told Newsweek that "many of the pollutants detected [at Chiquita Canyon] are present at many other landfills."

But when it becomes an issue is if those substances begin emitting beyond normal amounts, or start reacting with each other to form noxious gases.

Benzene can cause skin and eye irritations, but can also cause genetic defects and cancer. Prolonged or repeated exposure to the chemical can cause damage to the organs. Glass described it as "a nasty and very common industrial chemical" that gave the sweet smell to gasoline, but became problematic the more someone is exposed to it.

Dimethyl sulfide can cause skin, eye and lung irritation as a vapor, as well as dizziness and asphyxiation.

The EPA, which is leading the multiagency effort, has said that, as well as those two chemicals, chloromethane, carbon disulfide, toluene, hexane, tetrachloroethane, styrene and acrylonitrile have been detected at the landfill site. All are considered hazardous, if not toxic.

A South Coast Air Quality Management District (SCAQMD) spokesperson told Newsweek that "elevated levels" of hydrogen sulfide and benzene have been detected through sampling in the nearby community, as well as at the landfill site.

Glass said that the emissions would be a concern for workers on the landfill site, and that air monitoring would keep track of the levels around nearby housing, but suggested that residents should watch out for their sense of smell getting used to the odors, which was a person's "first warning sign."

"You can become desensitized to them and fail to smell them or detect them by odor—even when they're there, if you're having a lot of exposure to them—so residents in the area should also be concerned about that," he said.

Earlier in January, SCAQMD inspector Larry Israel told a hearing that the smell was "like a porta-potty" and "pretty horrendous." Nearby residents have taken to remaining indoors due to the odor, they told officials.

Brogan said that the taskforce's "highest concerns are possible health and environmental impacts, especially those raised by community members," and that the "overarching purpose" of the multiagency effort was to "marshal our collective expertise, resources, and tools to find short- and long-term solutions to the environmental and public health issues at the landfill."

According to local news outlet CNS, following a two-day hearing on the matter, Chiquita Canyon Landfill was directed to continue monitoring and controlling the excess emissions, but not to remove the pollutants causing them.

On January 16, Megan Morgan, an attorney acting on behalf of the landfill site, told residents and officials that it "understands and regrets that this is impacting its neighbors" and that it wanted to "slow and stop this reaction," which she indicated had remained of a constant size in the prior four months.

As the chemical reaction that is causing the gases and vapors is deep under the surface of the landfill, stopping the reaction altogether would first require understanding how the source was behaving, which could be "a really intractable problem, or at least difficult" without being able to reach it, Glass said.

For combustion to be occurring, he explained, the source could either be creating its own oxygen or air was able to reach it. Aside from excavating the reactive material, he suggested inert gases could be pumped into the landfill to push any oxygen out.

Brogan said the landfill operator had begun installing new gas collection wells and emission control devices to prevent the gases from releasing into the atmosphere.

"Potential health concerns associated with these pollutants are addressed by maintaining control of gases generated in the landfill through effective capture and destruction," he added. "The newly installed equipment will likely reduce emissions from the landfill."

As well as hazardous vapors, a soup of contaminated waste water—known as leachate—has been bubbling to the surface, which spilled into concrete-lined stormwater channels on the site's perimeter in the fall, according to the Los Angeles Times.

Glass described leachate as "pretty typically nasty stuff" that, if it makes it into nearby waterways or groundwater, can easily exceed health-based and aquatic benchmarks. "[In] a bad case scenario, you can see death of aquatic life," he said. "But there is a dilution factor that would occur too."

California is expected to see continued significant precipitation. Asked about the possibility of flooding causing an overflow at the landfill site, Glass said that to see high concentrations of contaminants in surface water, "I wouldn't expect that from leachate unless there was some sort of catastrophic failure, like a landslide or something that released a lot of leachate all at once."

Brogan said that, at present, there was "no evidence suggesting that the nearby waterways or groundwater have been contaminated by the landfill leachate or wastewater," adding that the Los Angeles Regional Water Quality Control Board was working to protect nearby water sources.

A spokesperson for the California Air Resources Board told Newsweek it was "actively supporting the efforts of the lead agencies to ensure that Chiquita Canyon Landfill expedites resolution of the nuisance odors," but that enforcement was directly overseen by SCAQMD.

A SCAQMD spokesperson said its January 17 order included requiring actions to reduce odors, including landfill excavation and removing exposed leachate, which were to begin "immediately to completely resolve the underlying landfill reaction as soon as possible, but an exact time frame for when that will be complete is not known."

Newsweek also approached Chiquita Canyon Landfill and the Los Angeles Regional Water Quality Control Board via email for comment on Wednesday.

Update 2/2/24, 4:20 a.m. ET: This article was updated to include comment from a California Air Resources Board spokesperson.

Update 2/5/24, 3:30 a.m. ET: This article was updated to include comment from a SCAQMD spokesperson.