Sterigenics’ Southern California Sterilization Facility Ordered to Close

The South Coast Air Quality Management District (South Coast AQMD) has ordered Sterigenics U.S. LLC to close its medical sterilization facility in Ontario, Calif., due to elevated ethylene oxide (EtO) readings near the plant.

South Coast AQMD’s approved Early Action Reduction Plan on April 7 had required the company to immediately address and reduce health risks from its EtO sterilization operations at the facility. The plan set interim thresholds to curtail operations upon persistent elevated EtO levels; specifically, it required the company to suspend operations if air monitoring results near the facility showed one EtO value at 17.5 parts ppb or higher. Repeatedly exceeding the threshold would result in a temporarily shutdown.

On April 12, April 15, and April 18, monitoring data showed EtO levels near the facility to be at 33.6 ppb, 24.3 ppb and 39.8 ppb respectively—well above the 17.5 ppb threshold. Consequently, the facility must remain closed for at least three days and cannot resume full operations until EtO levels drop below the 17.5 ppb threshold.
 
The Interim threshold is in place until all other actions committed to in the plan are implemented including the construction of a Permanent Total Enclosure (PTE) to prevent emissions from escaping the buildings, and implementation of an enhanced leak detection and repair system. Upon completion of these other actions, EtO levels should be substantially lower.

Sterigenics, a Sotera Health Company, has not commented on South Coast AQMD’s shutdown order. The company in recent years has been caught in the crossfire of controversy over the potential health hazards of EtO, a colorless, odorless carcinogenic gas used to sterilize about half of all medical devices on the market. Sterigenics closed its facility in Willowbrook, Ill., in 2019 and paid $408 million to settle more than 870 lawsuits over emissions from that plant. 
 
South Coast AQMD is communicating with other agencies, such as the U.S. Food and Drug Administration on the potential impacts to the sterilization industry. South Coast AQMD is also working towards stricter rules and requirements for EtO emissions from medical sterilization facilities as well as  reviewing new draft health standards for EtO released by the Office of Environmental Health Hazard Assessment.
 
Sterigenics uses EtO to sterilize medical equipment. The facility is in an industrial area in Ontario, with the nearest residential community is located more than a mile and a half away. Since June 16, 2022, South Coast AQMD has routinely collected 24-hour air monitoring samples adjacent to and nearby Sterigenics. The levels recorded are substantially higher than the 2021 annual average EtO concentration from the nearest South Coast AQMD regional monitoring station in Rubidoux, which is 0.06 ppbv (with a maximum value of 0.14 ppbv). 
 
EtO is a flammable, colorless gas used to sterilize medical equipment and make products including antifreeze, textiles, solvents, detergents, and adhesives. Short-term exposure to EtO may cause headaches, weakness, nausea, vomiting, diarrhea, difficulty breathing, eye and skin burns, and reproductive effects. The most significant public health risk is long-term exposure to EtO over a number of years due to an increased risk of certain cancers including lymphoid and breast cancer.
 
More information on South Coast AQMD’s investigation, as well as sampling data can be found here.
 
South Coast AQMD is the air pollution control agency for major portions of Los Angeles, Orange, San Bernardino, and Riverside counties, including the Coachella Valley. 

Read more: EPA Proposes New EtO Rules to Measure, Reduce Emissions