EtO Monitoring Results

Air samples collected by GHD Services, Inc. are sent to a laboratory for analysis. Once received, the results are shared with partner agencies then posted publicly on this page. The results indicate the levels of EtO in the air at the monitoring locations. These reported levels do not indicate your health or cancer risks. Learn more on our EtO Monitoring Frequently Asked Questions (FAQ) page.

Air Monitoring Results Spreadsheet

Updated May 18, 2020

Recent Updates

May 18, 2020 Update: First set of Phase III air monitoring results received

The Lake County Health Department has received the first set of Phase III air monitoring results from samples collected on three separate days from April 4 to April 11, 2020. This third phase of testing included samples collected up to May 1-2, 2020. The Air Monitoring Results spreadsheet will continue to be updated as additional results are received.

March 5, 2020 Update: Final set of Phase II air monitoring results received

The Lake County Health Department has received the final set of samples from Phase II of the ambient air monitoring for EtO.

On December 13, 2019, Medline Industries stopped EtO sterilization operations, and as of this date have not yet resumed. Samples collected after December 13, 2019 are representative of those non-operational conditions. As of this date, the Health Department has been informed by the Illinois Environmental Protection Agency (IEPA) that Medline is still undergoing testing of their additional pollution controls. After Medline has been permitted by the IEPA to resume full operations, a final 30-day period of monitoring will be conducted to provide post-control data.

January 27, 2020 Update: Phase II air monitoring concludes

Phase II of outdoor air monitoring concluded on January 22, 2020. The Health Department expects to receive the final results mid-February and will post them to this page. During the second phase of monitoring, over 350 samples were collected from 12 locations on 30 sampling days. This includes 14 sampling days during the temporary shutdown of EtO operations at Medline Industries, which began December 13, 2019.

A third and final 30-day period of monitoring will begin after Medline resumes its EtO sterilization operations. While monitoring is expected to resume in February, the exact date depends on when the Illinois Environmental Protection Agency (IEPA) has tested and approved Medline’s new emissions controls and the facility is fully operational. During the final phase, samples will be collected at the same 12 sites that were monitored during the second phase.

For more details, read the press release.

January 14, 2020 Update: Fourth set of Phase II air monitoring results received

The Lake County Health Department has received the fourth set of Phase II air monitoring results from samples collected on five separate days from December 4 to December 25, 2019. The Air Monitoring Results spreadsheet will continue to be updated as additional results are received. Medline has not been operating since the morning of December 13, 2019 as they are finalizing the installation of their additional emission controls. Therefore, samples collected on 12/13-12/14/2019, 12/16-12/17/2019, 12/19-12/20/2019, 12/22-12/23/2019 and 12/25-12/26/2019 are representative of air conditions without Medline operating. Phase II monitoring will be extended into February as a result of the delays with Medline’s additional emissions controls not yet being operational.

January 7, 2020 Update: Third set of Phase II air monitoring results received

The Lake County Health Department has received the third set of Phase II air monitoring results from samples collected on five separate days from November 19 to December 1, 2019. The Air Monitoring Results spreadsheet will continue to be updated as additional results are received.

December 12, 2019 Update: Second set of Phase II air monitoring results received

The Lake County Health Department has received the second set of Phase II air monitoring results from samples collected on five separate days from November 4 to November 17, 2019. The Air Monitoring Results spreadsheet will continue to be updated as additional results are received.

November 26, 2019 Update: First set of Phase II air monitoring results received

The Lake County Health Department has received the first set of results from the second phase of ethylene oxide (EtO) air monitoring. The initial results include samples collected on three separate days from October 26 to November 2, 2019. This phase of the air monitoring is set to continue through January 2020 and is being funded by the Illinois Environmental Protection Agency. 

To make the results more user-friendly, the Health Department is now linking to an online spreadsheet rather than embedding a table on this page. The Air Monitoring Results spreadsheet will be updated as additional results are received.

PRESS RELEASE: Ethylene Oxide Air Monitoring Results Received

August 14, 2019 Update: [Phase 1] final air monitoring results received; corrections to wind rose diagrams

The final air monitoring results from phase 1 are posted below. Please note that all maps have been revised to include adjusted wind rose diagrams that provide a more detailed gradient for wind speed, more distinctive coloring to better distinguish wind speeds, and corrected wind speed data. 

PRESS RELEASE: Final Ethylene Oxide Air Monitoring Results Received

July 24, 2019 Update: Additional air monitoring results received

Both Medline and Vantage conducted independent air monitoring in June 2019, some of which were done at sites also being monitored by the Health Department, the Village of Gurnee and the City of Waukegan. Results can be viewed here:

Medline air monitoring results

Vantage air monitoring results

Lake County Air Monitoring Wind Rose Maps

The maps posted below show the monitoring locations, air monitoring results by day, and a wind rose, which shows the wind information for each sampling day (i.e., wind direction, intensity, and percentage of time wind was blowing from the direction indicated). 

Wind roses are very important in determining the potential impact of a source of pollution. For more information, please see the U.S. EPA’s How to Read a Wind Rose (PDF).

  1. April 2020 Monitoring
  2. October 2019-January 2020 Monitoring
  3. June-July 2019 Monitoring

Lake County Air Monitoring Lab Reports

  1. April 2020 Monitoring
  2. October 2019-January 2020 Monitoring
  3. June-July 2019 Monitoring