The South Coast Air Quality Management District (South Coast AQMD) began investigating facilities within our jurisdiction that emit Ethylene Oxide (EtO) in March 2022, following the U.S. Environmental Protection Agency’s (U.S. EPA) reconsideration of the potential toxicity of EtO. South Coast AQMD is currently conducting special monitoring at three local facilities that conduct sterilization services for medical equipment, located in Carson, Vernon and Ontario.

Air Monitoring is being conducted at the facilities to identify sources of emissions. South Coast AQMD is looking into the facilities’ equipment to verify compliance with our rules and permit requirements and is evaluating immediate actions for the facilities to take to reduce and control emissions. Data so far shows emissions in surrounding communities to be at background levels.

EtO is a flammable, colorless gas that many industries use to make products including antifreeze, textiles, solvents, detergents and adhesives, as well as to sterilize medical equipment. Exposure to EtO can irritate the eyes and respiratory system and damage the nervous system. Short-term exposure to EtO may cause headaches, weakness, nausea, vomiting, diarrhea, difficulty breathing, eye and skin burns and reproductive effects. Long-term exposure to EtO over a number of years increases the risk of certain cancers including lymphoid cancer and breast cancer.

During South Coast AQMD’s monitoring efforts, the agency became aware of fugitive emissions from sources that were not previously known. As a result, South Coast AQMD is working on amending Rule 1405 to strengthen requirements to address fugitive emissions at these facilities which could include additional monitoring requirements. The rulemaking process, including Working Group meetings, are ongoing and open to the public. Upcoming meeting dates can be found at the Proposed Amended Rule 1405 page.

For more information, please visit our EtO Emissions Investigation webpage.