On May 6, 2022, the County received a Proposition 65 Notification from the South Coast Air Quality Management District (SCAQMD) identifying a release of ethylene oxide from Sterigenics, a medical sterilization facility in Vernon. SCAQMD is the regulatory entity that is responsible for air monitoring and enforcing air regulations. Ethylene oxide is a flammable, colorless gas used by Sterigenics to sterilize medical equipment. Exposure to ethylene oxide can irritate the eyes and respiratory system and damage the nervous system. Short-term exposure to ethylene oxide may cause headaches, weakness, nausea, vomiting, diarrhea, difficulty breathing, eye and skin burns, and reproductive effects. Long-term exposure to ethylene oxide over several years increases the risk of certain cancers including lymphoid cancer and breast cancer in females. Sterigenics operates two facilities that use ethylene oxide to sterilize medical devices. Both facilities are located between 49th St. and 50th St. on Gifford Ave., which is an industrial area within Vernon. These facilities are near residential areas within the City of Maywood. The nearest Maywood residential area is located approximately 500 feet away, and the nearest school is about 1700 feet away.
On September 2, 2022, Sterigenics provided South Coast AQMD with the Early Action Reduction Plan required as a "Potentially High-Risk Level Facility." The Plan includes an Air Toxics Inventory Report (due 11/4/22), a Health Risk Assessment (due 12/6/22), and a Risk Reduction Plan (due 12/6/22); and was approved by South Coast AQMD on September 9, 2022. As of March 2023, all documents have been submitted to AQMD. On September 9, 2022, the South Coast AQMD approved Sterigenics' Early Action Reduction Plan. Risk reduction measures in the Plan include temporary enclosures such as plastic sheeting, directing fugitive emissions to control equipment, perimeter monitoring which may include smoke tests, maintenance of onsite records, ventilation of areas with fugitive emissions to portable capture and control equipment, evaluation of other interim measures and technologies, sealing off building draft openings that are not under negative pressure, installation of signage in areas with known fugitive emissions, implementation of a building differential pressure monitoring plan, leak detection, installation of dry beds to control fugitive emissions, and periodic fenceline air monitoring.
Part of the Early Action Reduction Plan approved by South Coast AQMD includes a temporary threshold for ethylene oxide emissions from the facility of 17.5 ppb. If any of the South Coast AQMD or Sterigenics monitors detect levels above 17.5 ppb, a curtailment of allowable operations at the facility will be put into place. That curtailment is dependent on the number of exceedances in a 30-day period and the measured level of ethylene oxide. The curtailment actions include an allowable reduction in operations of 20%, 50% or 100% at the facility. This plan is to stay in place until permanent engineering controls are approved by South Coast AQMD and put in place by Sterigenics. South Coast AQMD staff identified deficiencies and rejected the draft Air Toxics Inventory Report and is in the process of reviewing the Health Risk Assessment and Risk Reduction Plan.
AQMD is also in the process of updating Rule 1405, the Control of Ethylene Oxide and Chlorofluorocarbon Emissions from Sterilization or Fumigation Processes, to incorporate new information and technologies into the rule. 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. It is expected that the amended Rule 1405's new requirements will be effective for all facilities in the region as of 12/31/24.
South Coast AQMD continues to collect air grab samples at the Maywood community location. Sampling results continue to show levels of ethylene oxide in the community to be generally consistent with the regional background level range (please see Figure 1).
Sampling results at SCAQMD Ethylene Oxide air quality monitoring Site 1 (just outside the facility), and at Site 3, on Gifford Avenue, did not exceeded the State offsite worker cancer risk limit of 3.18 parts per billion during the last three months. The temporary threshold of 17.5 ppb was not exceeded in any instance so there were no curtailments of operations. Additionally, South Coast AQMD reports that off-site worker cancer risk drops off substantially (about 50 times lower) a short distance away (approximately 150 feet), from the facility.
Sterigenics has also been operating its own two air monitors around the facility and has recently begun operating a third monitor. Since July 2023, the readings from these monitors have been below the 100/million offsite worker cancer risk threshold of 3.18 parts per billion (please see Figure 3).
At this time, no specific action is required by community members.
For more information on Ethylene Oxide emissions at Sterigenics in Vernon, please visit the South Coast Air Quality Management District's Sterigenics Emissions Investigation in Vernon website.
If you live near the Sterigenics facilities and are experiencing bad smells, you can report odors by calling: 800-CUT-SMOG (1-800-288-7664) Or filing a complaint online: www.aqmd.gov/home/air-quality/complaints
If you have questions regarding health concerns Call:
626-430-9821
Email:
tox@ph.lacounty.gov
