Who is ATSDR?

ATSDR is the Agency for Toxic Substances and Disease Registry. It is a federal public health agency of the U.S. Department of Health and Human Services.  According to its website, ATSDR protects communities from health effects related to exposure to natural and man-made hazardous substances.     

What is the ATSDR report?

The ATSDR report from August 22, 2018, is a technical report on recent Ethylene Oxide (EO) emissions monitoring for a two-day period in May 2018 in the Willowbrook, Illinois, area.  At the August 29, 2018 Village of Willowbrook townhall meeting, ATSDR stated that the purpose of the report was to inform regulatory decisions and not to communicate real-world risk to the public.  For example, ATSDR clarified that the report is based on assumptions that are unrealistic and worst-case measurements that are biased for regulatory decision-making purposes.  

What are the key findings from the ATSDR report?

The published ATSDR report from August 22, 2018, indicated that exposure to emissions from EO in the Willowbrook, Illinois, community presents a “public health hazard” based on the unrealistic assumptions made in the report.  On August 29, 2018, at the Village of Willowbrook townhall meeting, ATSDR clarified that “(the report) was not one that indicated immediate health threat or that there was an emergency situation.”

Furthermore, the ATSDR report concluded that measured and modeled ethylene oxide concentrations indicate that non-cancer health effects are unlikely for residents and off-site workers in the Willowbrook community surrounding the Sterigenics facility.

Why does ATSDR continue to state that the Sterigenics Willowbrook facility poses “No Immediate Health Threat” after it issued its report?

Below are some important facts that may help explain ATSDR’s clarifying statements:

  1. EO occurs naturally.  There is far more EO internally produced within our own bodies, than the risk level stated in EPA’s Integrated Risk Information System (IRIS) risk assessment.

    • Healthy human bodies internally produces EO.  Published research on Internally-Produced Equivalent EO values (Kirman and Hayes 2017) concluded that the mean normal internally produced level of a non-smoker is 19,000 times greater than the risk level stated in the recent EPA IRIS risk assessment.  

  2. There are many sources of background EO apart from the Sterigenics facility that were not taken into account in the ATSDR report.  

    • EO is emitted into the atmosphere from a number of sources every day.  Hospitals, plants, microbes, and combustion of plant material and fuel are just a few of the contributors to background EO. 

    • According to World Health Organization data, cigarette smoke releases 1,100 times more EO than emission samples cited in the recently published ATSDR report.

    • There are more than a dozen hospitals in DuPage and Cook counties that use EO for sterilization of medical devices and emit EO.

    • An EPA background monitoring program found EO in many samples around the U.S.

  3. The ATSDR risk analysis was heavily biased to the worst case short-term scenario, which is an unrealistic predictor of the long-term levels of exposure to EO.

    • ATSDR relied upon the highest concentration detected in the residential area samples collected by USEPA, under non-representative weather conditions, for the general population risk estimate.  This is not reflective of long-term exposures.

    • In addition, in its evaluation, ATSDR intentionally excluded from consideration 21 of 39 samples that it acknowledged reflected lower overall measured levels. 

    • As the author of the ATSDR report stated at the Village of Willowbrook townhall meeting, the EPA “biased the model on purpose to try and capture what might be the worst exposure in the community.”  The ATSDR author further said, “I don’t know if anyone’s home 24 hours a day, 7 days a week for an entire year for 33 years, which is what we assumed.”

  4. The study does not take into account the voluntary upgrade to the Sterigenics Willowbrook facility to further lower emissions that was implemented in July, 2018.

    • Emissions prior to the upgrade were well below USEPA & Illinois EPA permit compliance levels. The Willowbrook facility had emissions controls that exceed Illinois EPA permit requirements for an estimated 99% of process emissions.

    • The voluntary changes made by the upgrade control the remaining process emissions, which have reduced the already low emissions by an additional 90%, resulting in EO levels far below those conservatively modeled by ATSDR.

What other concerns are there with the accuracy of the ATSDR report?

Sterigenics is committed to safety, and Sterigenics continues to evaluate the ATSDR report and the EPA sampling data.  As our review continues, we have noted some additional errors in the report.  For example, the sampling method was flawed and there were errors in the preparation of the report.

  • To measure the small amounts of EO collected in the USEPA’s sampling devices, their laboratory used a customized method.  No scientific control samples were reported and USEPA did not provide validation and quality control information to allow independent evaluation of the results.

  • ATSDR specified a risk criterion that is much lower than laboratories generally can measure.  This is an impractical goal to apply since there is no practical way to measure EO concentration levels or demonstrate that those levels meet this guideline level, in particular for a substance that occurs in nature and is present in the background environment.

  • ATSDR misstated the number of samples collected by USEPA and mis-tabulated their results in the report on risk estimates.  These errors point out the importance of transparency in the data used to state report conclusions.