Sterigenics Willowbrook Facility - Latest Update
On this page
- Update February 8, 2019
- Update February 5, 2019
- Update January 28, 2019
- Update December 18, 2018
- Update December 13, 2018
- Update December 7, 2018
- Update November 23, 2018
- Update November 21, 2018
- Update November 14, 2018
- Update November 5, 2018
- Update October 24, 2018
- Update October 10, 2018 (link to stack test results added 11.20.2018)
Update, February 8, 2019
A recording of the February 5, 2019 webinar is available here.
Update February 5, 2019
Results for air quality samples taken in late November and December 2018.
EPA has posted results for 12 days of air quality monitoring in Willowbrook: November 25 and 28, and December 1, 6, 7, 10, 13, 16, 19, 22, 26 and 28. EPA will use all the data as part of a full assessment of risk from ethylene oxide in Willowbrook, which we expect to complete by Spring 2019.
With these results, seven weeks of data are now available. Based on the full data set to date, EPA notes:
- The two sites located closest to the two Sterigenics buildings are seeing the highest ethylene oxide concentrations. Average readings are a little over 2 micrograms per cubic meter; however, there have been readings as high as 10 and 11 micrograms per cubic meter.
- Monitors at the six community-oriented sites are seeing ethylene oxide concentrations that are consistently on the order of a few tenths of a microgram per cubic meter.
- At community-oriented monitors upwind of the Sterigenics buildings, ethylene oxide concentrations generally have ranged from 0.1 to 0.5 micrograms per cubic meter.
- At the community-oriented monitors downwind of the Sterigenics buildings, ethylene oxide concentrations have occasionally been as high as 1.7 micrograms per cubic meter.
- Despite the additional data, monitoring information about ethylene oxide in the Willowbrook area remains limited. It remains premature to draw conclusions about long-term health risks from the data. EPA is continuing to monitor in the Willowbrook area and will continue to post data as it becomes available. We expect to post data from several January sampling days soon.
- EPA will use all the data as part of a full assessment of risk from ethylene oxide in Willowbrook, which we expect to complete by Spring 2019.
- Note: as part of EPA’s ongoing quality assurance efforts, the agency has updated a few results from November. These updates apply to a small number of lower concentration values; they do not change any of the higher values.
Update January 28, 2019
Status of ethylene oxide monitoring data
EPA is completing steps to assure the quality of air quality samples taken in the Willowbrook community in December 2018, as well as during the government shutdown in January 2019. We will post results as soon as possible.
Update December 28, 2018
New questions and answers were added to the Frequent Questions page on December 20 and 28th.
Update December 18, 2018
Slides from the December 18th webinar are available here.
Update December 13, 2018
EPA webinar: Update on Ethylene Oxide Monitoring in Willowbrook, Illinois
The U.S. Environmental Protection Agency will hold a webinar Tuesday, December 18, 2018, to provide updates on ethylene oxide monitoring in Willowbrook, Ill. For more information on this webinar, please review the details below:
Date: Tuesday, December 18, 2018
Time: 1:00pm -2:00pm (CST)
Meeting Link: https://epawebconferencing.acms.com/willowbrook/
Call in Number: 833-819-8005
Conference ID: 1898022
*Note: A maximum of 500 people may attend the webinar at any one time. EPA plans to record the webinar and post it to the website.
- Opening remarks
- Review of ethylene oxide monitoring plan
- Recent monitoring results
- Monitoring next steps
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Update December 7, 2018
EPA has posted results for three days of air quality monitoring in Willowbrook: November 13, 16 and 19
- Monitors detected ethylene oxide in the air at the two sites closest to the Sterigenics facility.
- Monitors did not detect ethylene oxide at the six community-oriented sites -- those at schools and in residential areas.
- It is premature to draw conclusions from the data. EPA plans to continue monitoring in the Willowbrook area for three months and will continue to post data as it becomes available.
- EPA will conduct a full assessment of risk from ethylene oxide in Willowbrook, which we expect to complete by Spring 2019.
- On November 21, 2018, EPA announced that it had identified an issue with the analytical method used in previous EPA monitoring. We have changed the analytical method, so that the issue does not affect these results.
- Open House and Public Meeting on Ethylene Oxide
The U.S. EPA will host an open house and community forum to provide updates on the agency’s work to better understand air emissions of ethylene oxide from the Sterigenics facility in Willowbrook, Illinois. Both will be held Thursday, November 29, 2018 at Ashton Place, 341 75th St, Willowbrook, Ill. Learn more.
- Potential Issue Regarding Previous Ethylene Oxide Monitoring Results
U.S. EPA recently discovered an issue with the way ethylene oxide has been measured. As a result of the issue, monitors may have reported higher ambient levels of ethylene oxide than actually exist. More specifically, the chemical Trans-2-butene can be incorrectly identified as ethylene oxide when air quality samples are being analyzed in a laboratory. Trans-2-butene can be released from petrochemical industrial processes and the burning of fossil fuels. EPA discovered the issue as part of its work to improve the analysis method for ethylene oxide.
- What this Means
This discovery means that the results of air quality monitoring conducted prior to October 2018 may have shown higher concentrations of ethylene oxide than were actually in the air. This includes air quality monitoring that U.S. EPA’s Region 5 conducted in mid-May 2018 in Willowbrook, Illinois. U.S. EPA cannot fully evaluate the difference between reported and actual ethylene oxide concentrations, as the samples of air collected in mid-May are no longer available for analysis. U.S. EPA has made a change to its analytical method to prevent this issue in the analysis of future air quality samples – including those from monitoring started in November 2018 in the Willowbrook area. U.S. EPA is making the technical information about this change available for other laboratories.
- Does the monitoring issue change EPA’s conclusions in the National Air Toxics Assessment (NATA)?
No. U.S. EPA would have been concerned about ethylene oxide in Willowbrook, even without air quality monitoring
.U.S. EPA’s NATA identified census tracts in the Willowbrook area as a potentially higher risk community. NATA is based on air quality modeling: it does not rely on any air monitoring data.
In addition, in the health consultation conducted for U.S. EPA Region 5, ATSDR relied on both the Region’s modeled estimates of ethylene oxide in the outdoor air in the area near the Sterigenics facility as well as the results of the monitoring the Region conducted in mid-May.
- What this Means
EPA is monitoring the outdoor air near the Sterigenics facility to better understand levels of ethylene oxide (EtO) in the air. The first monitors began collecting air samples on November 13, 2018. Learn more.
EPA will hold a community meeting on November 29, 2018. We will post more information once we finalize time and location.
EPA has set up a dedicated email address for inquiries related to ethylene oxide and the Sterigenics facility in Willowbrook, IL. Emails should be sent to EtO@epa.gov.
What is EPA doing to reduce ethylene oxide from the Sterigenics facility?
What has been done to date:
Sterigenics has taken steps to further control ethylene oxide emissions from the Willowbrook facility and estimates that those controls have reduced ethylene oxide by about 92 percent.
On September 20 and 21, 2018, a contractor hired by Sterigenics conducted stack tests to measure the actual emissions from the control devices at the facility. U.S. EPA and Illinois EPA experts were present to observe the tests.
What happens next:
- Once the final report from the stack test is complete, and delivered to U. S. EPA, the Agency will review the results to confirm how much ethylene oxide the pollution controls are reducing. EPA will that information to estimate current emissions from the Sterigenics facility.
- U.S. EPA needs the emissions estimates to help the agency determine how far any remaining ethylene oxide emissions will disperse and what the levels of ethylene oxide in the air nearby the facility are likely to be. EPA will determine this using a computer model.
- The information also will help EPA determine the best places to monitor the air for ethylene oxide in the area. EPA will work with local elected officials in the area as it develops its monitoring plan.
- Existing monitoring methods are not sensitive enough to detect ethylene oxide at all levels in the outdoor air. Because of this, EPA cannot use monitoring alone to determine the levels of ethylene oxide in the air around the facility.
- EPA will conduct a risk assessment for the Willowbrook area. This assessment will be more comprehensive than either NATA or the ATSDR analysis. It will be similar to the types of risk assessments EPA conducts when it is reviewing its regulations for industries that emit air toxics to determine whether those rules need to be updated to improve protection of public health.
- EPA will update this information as this work proceeds on our website at: https://www.epa.gov/il/sterigenics-willowbrook-facility