On June 16, 2020, the Lake County Health Department (LCHD) posted the last set of results from the final phase (Phase III) of EtO air monitoring, which included samples collected between April 4 and May 7, 2020.
In the last data set, there were five sample results that the analyzing laboratory (Eastern Research Group) noted as “possible void” due to the amount of vacuum pressure measured in the canister at the laboratory. LCHD discussed the reports with the contractor performing the air monitoring, GHD Services, Inc. GHD made the professional decision to invalidate and not report these results. Because the canister pressures measured at the lab were outside of what is required by the test methodology (Method TO-15), they could not be validated.
U.S. Environmental Protection Agency air test methods can be viewed here:
The lab sheets with the results were posted, and the compiled spreadsheet on the LCHD web page indicated the following result: “Not reported = Sample result not reported; remaining pressure in canister was outside test method parameters.” The posted maps provided by GHD did not report the invalidated results.
Based on the five “not reported” sample results and other inquiries received, including from the Agency for Toxic Substances and Disease registry (ATSDR), Stop EtO Lake County, and Vantage Specialty Chemicals, LCHD reached out to the U.S. Environmental Protection Agency (EPA) for assistance in reviewing the Phase III sample set to verify the results’ validity. The EPA has provided a great deal of technical support to this air monitoring effort, so LCHD once again sought their expertise in reviewing the data. LCHD sent the formal request to the U.S. EPA on September 2, 2020.
The EPA indicated that they needed additional quality control/assurance information from the laboratory and contractor to conduct a comprehensive review. LCHD was also in communication with the ATSDR, and they requested the additional information as well. To obtain the information, LCHD requested instrument calibration data, chromatographs from the sample analyses, field collection and chain-of-custody sheets. All of this information was collected and provided to the EPA and ATSDR for Phase III; receipt of the laboratory chain-of-custody sheets for Phase I and II (which contain the original canister pressure from the laboratory) is pending.
Having received all of the information for Phase III, the EPA reviewed of all of the pressure data “blind to reported EtO concentrations,” and developed conclusions regarding the validity of the results. The EPA’s conclusions are included in this letter, which LCHD received on October 6, 2020. As a result of this review by the EPA, the sample data table for Phase III on our web site was updated to incorporate the EPA’s findings.
The EPA’s letter did not address the five sample results that were “not reported” by GHD Services Inc., as they reviewed only reported results, but a follow-up email exchange with the EPA indicated that the agency concurs with the earlier determination by GHD to invalidate the five sample results because the canister pressures were outside of required method parameters.
LCHD will continue to work with the EPA and the ATSDR, as well as the Illinois EPA, to assist them in any way we can. The complete quality assured/quality-controlled monitoring dataset (Phase I – III) will be reviewed by the ATSDR for their health risk assessment. The Illinois Department of Public Health has also agreed to then conduct a cancer incidence rate study after the health risk assessment is completed.
For more information, visit our Ethylene Oxide in Lake County webpage.