What’s being done to protect SoCal residents from the potential harms of a cancer-causing chemical?

Vernon is an almost exclusively industrial city just southeast of downtown Los Angeles. And one of the companies that operates within Vernon has recently become the target of lawsuits over its use of a chemical called ethylene oxide, a colorless, flammable gas used to sterilize medical supplies. It’s also a known carcinogen.

As the lawsuits make their way through court, local air regulators say they are working to protect residents and off-site workers from potentially harmful chemical emissions.

And not just in Vernon — air regulators are monitoring ethylene oxide levels at more than a dozen facilities in Greater L.A.

What is ethylene oxide and who monitors it?

Because it can be used on a wide range of materials, ethylene oxide is well-suited for sterilizing medical equipment. But public health officials say long-term exposure to it can increase one’s risk of developing certain cancers, as well as reproductive issues.

The South Coast Air Quality Management District (SCAQMD) is responsible for monitoring the air and enforcing regulations in L.A., Orange, Riverside, and San Bernardino counties.

There are currently 15 facilities that use ethylene oxide to sterilize medical equipment under the agency’s jurisdiction, according to Susan Nakamura, SCAQMD’s chief operating officer. There is also one facility devoted to ethylene oxide aeration, which is the process of removing residual gas from items that have been sterilized.

SCAQMD began investigating facilities that use ethylene oxide in March 2022. At the time, the Environmental Protection Agency was revising its regulations on the chemical’s potential toxicity after a ProPublica analysis found that ethylene oxide was the biggest contributor to excess industrial cancer risk from air pollutants nationwide.

Ethylene oxide’s use in Vernon

Community members and workers in Southeast L.A. County have filed separate lawsuits against Sterigenics U.S. LLC, a company that sterilizes medical equipment in Vernon.

Each lawsuit alleges the company knowingly exposed people to unsafe levels of ethylene oxide without warning them of the potential health risks.

Sterigenics has denied any wrongdoing. In an email, spokesperson Kristin Gibbs told LAist that the company “empathizes with anyone battling cancer,” but that it’s “confident that it is not responsible for causing the illnesses.”

“We will vigorously defend our essential and safe operations against these claims,” she added.

What do air regulators do to protect residents?

The agency investigates issues at regional facilities and posts those results as well.

For example: In May 2022, SCAQMD issued a Notice of Violation to the Sterigenics building on 50th Street. According to the agency, the building operators:

• failed to operate its air pollution control system in accordance with its permit and in good condition; and
• failed to include a differential pressure gauge and a pH meter in its control equipment. That violation has since been resolved. 

A few months later, SCAQMD issued additional Notices of Violation to the company for installing control equipment at both of its buildings without permits. Those violations have also been resolved.

Throughout that time, multiple public officials asked the agency to shut down Vernon Sterigenics until it no longer posed a public health risk, including state Assemblymember Miguel Santiago and L.A. County Supervisor Janice Hahn. The latter wrote:

Maywood residents spend time outdoors during a hot afternoon.

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Brian Feinzimer

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LAist

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Residential buildings in Maywood are in close proximity to industrial facilities in neighboring Vernon.

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Brian Feinzimer

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LAist

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The agency can also apply labels to companies that correspond to a level of risk.

In June 2022, for example, SCAQMD designated Vernon Sterigenics as a “Potentially High-Risk Facility.” That designation is used when emissions data show it has the potential to exceed a cancer risk threshold greater than 100 chances in a million, or that it already has. Sterigenics was then required to provide an emissions reduction plan and ordered to make a number of upgrades. Some are still in the process of being fulfilled.

To mitigate the potential impact of the Vernon facility’s emissions, “we used every tool in the tool box,” said Nakamura, SCAQMD’s chief operating officer. “We take the protection of public health very seriously.”

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Are air regulators confident in their ethylene oxide monitoring results?

As Hahn noted in her letter to SCAQMD, Southeast L.A. County’s proximity to Vernon has made it especially vulnerable to environmental issues. This includes contamination from Exide, a now-shuttered battery recycler that spewed lead and arsenic into Bell, Boyle Heights, Commerce, East L.A. Huntington Park, and Maywood for decades. Local residents also live close to freeways and other industrial facilities.

To make sure SCAQMD’s ethylene oxide monitoring results are precise, the agency employs a two-step process. Jason Low, deputy executive officer of the agency’s monitoring and analysis division, told LAist that the process requires air quality regulators to take a few seconds of air samples near the facility, then more samples as they move away. Those samples are sent to the agency’s lab for analysis.

SCAQMD also has a mobile platform, which “can detect signals related to ethylene oxide in real time,” Low added.

“So we can drive around the facility, and then we can drive away from the facility and see how the levels of ethylene oxide change,” he said.

Once the agency determines that there are elevated ethylene oxide emissions near a sterilization facility, it puts up canisters near and around it, including in local residential areas. These canisters take samples over a 24-hour period. Then, those canisters are also taken to the lab.

“We're one of the few laboratories in the nation that can do this,” Low said.

Nearby residents are unlikely to see the warning signs on the Sterigenics buildings in Vernon.

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Brian Feinzimer

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LAist

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What else is being done to protect local residents?

On the outer walls of Sterigenics in Vernon, there are signs that read: “This facility contains one or more chemicals known to the state of California to cause cancer, birth defects, or reproductive harm.”

These signs are required by state law. Similar ones can be found throughout California, including in parking lots and in the coffee section of grocery stores. The signs are meant to help Californians make informed decisions about their exposure to potentially harmful chemicals. But their utility is unclear, particularly when it comes to those who live around Sterigenics.

Vernon is almost entirely industrial, with only a few hundred residents. People who live in surrounding neighborhoods don’t necessarily enter the city, unless they work there. As a result, they may be unlikely to see those warning signs.

Earlier this summer, LAist knocked on the door of 60 homes in Maywood, just a few blocks from Sterigenics in Vernon. About a dozen residents answered the door. None of them had ever heard of ethylene oxide.