Air Monitoring Finds Elevated Levels of Cancer-Causing Ethylene Oxide in Salinas, Puerto Rico
Preliminary results show that the chemical's risks still persist in local communities
For years, Earthjustice has represented community and environmental groups seeking stronger regulations for sterilizer facilities. EPA conducted air monitoring in 2022 near the Steri-Tech facility in Salinas, Puerto Rico, and found ethylene oxide (EtO) levels that raised significant concerns about cancer risk. To provide more current information about EtO levels in the surrounding community, Earthjustice commissioned additional monitoring beginning in July 2026, and the preliminary results were shared at a community meeting in Salinas on Oct. 1, 2026.
The preliminary monitoring results, completed by scientist Rick Peltier of Dirigo Innovations, shed light on the ongoing dangers of EtO emissions in Salinas. Shown in the map below, the July 2026 monitoring detected EtO across La Margarita and Brisas del Mar neighborhoods to the west and northwest of Steri-Tech. EtO concentrations measured downwind of the facility were substantially higher than concentrations measured upwind, indicating that emissions from Steri-Tech are contributing to elevated EtO levels in the surrounding community.
Measurements taken over seven days show ethylene oxide levels across six sites in Salinas.
Peltier explained that the preliminary results show that downwind EtO concentrations in Salinas averaged 2.2 parts per billion (ppbv). Chronic exposure to EtO causes serious health risks at concentrations far below levels measured by Earthjustice in 2026 and EPA in 2022. The EPA’s 2016 IRIS assessment establishes 0.011ppbv as the average concentration of ethylene oxide that a person may breathe over a 70-year lifetime without being expected to exceed a 1-in-10,000 risk of contracting cancer from ethylene oxide exposure. EPA’s modeling and monitoring in 2022, and Earthjustice’s monitoring in 2025 and 2026, consistently show average airborne ethylene oxide concentrations in the communities surrounding Steri-Tech that are multiples greater than 0.011ppbv.
This map shows a range of ethylene oxide measurements taken at Salinas and six other locations across the U.S.
More than 14 million people in the United States and its territories, including Puerto Rico, live near sterilizer facilities that emit ethylene oxide, one of the most toxic air pollutants regulated by EPA. With seven sterilizers on the island, Puerto Rico faces a disproportionate impact from EtO pollution from sterilizers.
EtO is highly toxic, even at low concentrations. Exposed community members are at an increased risk of health harms from ethylene oxide, including breast and blood cancers, pregnancy loss, developmental challenges, and other impacts.
Additional monitoring results and a final analysis are expected in the coming months.
Earthjustice’s Washington, D.C., office works at the federal level to prevent air and water pollution, combat climate change, and protect natural areas. We also work with communities in the Mid-Atlantic region and elsewhere to address severe local environmental health problems.
Tylar Greene
Public Affairs and Communications Strategist, Earthjustice
tgreene@earthjustice.org
