A study conducted between July and September detected elevated concentrations of ethylene oxide (EtO), a carcinogenic chemical, in communities near Steri-Tech, Inc. in Salinas, Puerto Rico, according to Earthjustice and the Comité Diálogo Ambiental. The analysis, commissioned from scientist Rick Peltier of the firm Dirigo Innovations, examined samples from the La Margarita and Brisas del Mar communities.
Concentrations were higher in downwind measurements, which points to the company’s emissions contributing to the levels detected. The average recorded was 2.2 parts per billion (ppb). The federal Environmental Protection Agency’s (EPA) IRIS assessment establishes that an average exposure of 0.011 ppb over 70 years corresponds to an estimated cancer risk of one in 10,000.
EtO exposure is associated with risks of breast and blood cancer, pregnancy loss and developmental problems, among other adverse effects. The EPA filed a proposed settlement in federal court to resolve alleged Clean Air Act violations by Steri-Tech. The measure would require the company to cut 99.99% of emissions from the vents of its sterilization chambers.
However, Earthjustice and the Comité Diálogo Ambiental warn that the agreement leaves other parts of the process without sufficient oversight and does not adequately address past violations. The organizations demanded stricter controls, transparent monitoring and publication of compliance reports. They also asked the EPA to honor its earlier commitment to fund an epidemiological study of the emissions’ effect on residents’ health.
The agency detected worrying EtO levels in 2022 and filed the case over alleged violations in June 2025.