Earthjustice and the Comité Diálogo Ambiental announced on Thursday, October 1, 2026, that a study detected an average of 2.2 parts per billion (ppb) of ethylene oxide (EtO), a carcinogenic chemical, in the air of the La Margarita and Brisas del Mar communities in Salinas. That is far above the 0.011 ppb level that the federal Environmental Protection Agency (EPA) associates with a cancer risk of 1 in 10,000.
According to the EPA’s 2016 IRIS assessment, 0.011 ppb is the average EtO concentration a person can breathe for 70 years without the risk of cancer being expected to exceed that level, the organizations said. They added that EPA models and measurements, as well as Earthjustice’s own, consistently show concentrations several times above that level in communities near Steri-Tech.
The study, conducted between July and September, was commissioned by Earthjustice from scientist Rick Peltier of the firm Dirigo Innovations, who is also a professor at the University of Massachusetts Amherst. Samples were taken in La Margarita and Brisas del Mar, west and northwest of Steri-Tech. Peltier said EtO concentrations measured downwind of the facility, toward the community, were substantially higher than those measured upwind, indicating that Steri-Tech’s emissions contribute to elevated EtO levels in the surrounding community.
He explained that chronic exposure to EtO carries serious health risks at concentrations even lower than those Earthjustice detected in 2025 and 2026 and the EPA detected in 2022. The organizations noted that EtO is an invisible, odorless gas, smelling only at high concentrations, and is highly toxic even at low concentrations.