June 6, 2020

Sampling in an Engaged Community: Ethylene Oxide Exposures in Willowbrook, Illinois

By Ed Rutkowski

An industrial hygienist from a consulting firm that participated in the sampling of ethylene oxide (EtO) in the Willowbrook, Illinois, community discussed his experiences June 1 as part of a prerecorded virtual session at AIHce EXP 2020. The presenter, Benjamin Chandler, CIH, CSP, of GHD Services in North Little Rock, Arkansas, shed light on the sampling challenges associated with a case that drew national attention and resulted in the shuttering of a Willowbrook facility.

The chain of events began in August 2018, when EPA released information indicating that residents of Willowbrook and surrounding areas were at increased risk of cancer from exposures to EtO. The gas was being emitted by Sterigenics, whose Willowbrook facility uses EtO to sterilize medical devices. EPA’s determination was driven by a change in the cancer risk basis for EtO in the agency’s Integrated Risk Information System. The change indicated a 30-fold increase in cancer potency, accompanied by an escalation of EtO’s status from “probably carcinogenic to humans” to “carcinogenic to humans.”

Sterigenics, which was informed of EPA’s sampling results in June 2018, had already installed controls to its Willowbrook facility that reportedly reduced EtO emissions by 90 percent. But the Willowbrook community was alarmed by EPA’s findings, which were detailed in a report (PDF) by the Agency for Toxic Substances and Disease Registry. Reportedly frustrated by a lack of answers at a public forum attended by 400 people, the Village of Willowbrook formed its own task force to investigate the issue. The task force hired GHD to conduct sampling.

Chandler, who participated in the task force along with a toxicologist, a chemical engineer, and representatives from Willowbrook, explained to AIHce attendees that the objective of the sampling was to identify strategies for measuring EtO in the community, including indoor, outdoor, and background levels, and to use that information to provide guidance. The project was “ground zero for EtO and the contributions of medical sterilization facilities,” Chandler said, referring to other communities that have since hired third parties to investigate EtO emissions in their local areas.

One challenge for the sampling project was identifying laboratory methods. Several options exist for collecting air samples in workplaces, Chandler said, but criteria for community exposures were much lower. “We were unable to initially find a method with a laboratory that gave us a low-enough detection limit,” Chandler explained. Eventually, a few labs modified their methods and achieved a detection limit of around 0.02 parts per billion, a level that allowed comparison to limits set by the American Chemistry Council and the Texas Commission on Environmental Quality—24.5 ppb and 40 ppb, respectively—that correspond to a 1-in-10,000 risk of cancer. However, the new detection limit was still not low enough to work with EPA’s estimated 1-in-10,000 cancer risk level for EtO of 0.01 ppb.

The sampling method followed EPA TO-15, Determination Of Volatile Organic Compounds (VOCs) In Air Collected In Specially-Prepared Canisters And Analyzed By Gas Chromatography/Mass Spectrometry (PDF). Samples were collected in 6-liter evacuated summa canisters beginning in November 2018. By then, Chandler said, interest in the project had grown significantly, drawing the attention of organizations such as the American Chemistry Council and advocacy groups. Because EtO is transported by rail, transportation groups became interested in the project, as did other medical sterilization companies. Some groups arranged to conduct their own sampling. Chandler said at some sites as many as six canisters were set up in a single location.

Eventually sampling expanded from DuPage County, where Willowbrook is located, to areas in Lake County north of Willowbrook.

Willowbrook residents took a keen interest in the task force, filling meeting rooms for town hall discussions. “Once the public became aware of sampling, very quickly we had to transfer these town hall meeting to larger venues,” Chandler said.

By the time sampling concluded in August 2019, Chandler said his team had taken more than 200 ambient air samples of indoor and outdoor environments, from areas upwind and downwind of the Sterigenics facility. Sampling times were varied to acquire samples while the Sterigenics facility was operating and when it was closed. “At the time, this was the largest sampling area for EtO ever surveyed,” Chandler said.

Chandler’s team consistently found background levels of EtO above the EPA risk criteria up to three miles from the facility. Detectable levels of EtO were found inside residences and businesses. “Some of the data we collected ultimately was used to issue a seal order to Sterigenics,” Chandler said.

He commended the Willowbrook leaders for funding such a large sampling project and informing their community of its progress. “We have a very educated public these days, with information being shared quickly and on a large basis,” he said.

Not long after the sampling project ended, Sterigenics announced it would permanently close its Willowbrook plant.

Ed Rutkowski is editor-in-chief of The Synergist.