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ATSDR Press Room

ATSDR Changes Conclusions About TCE Exposure in Millsboro, DE

Sussex County, Millsboro, Delaware

Friday, August 17, 2012

The Agency for Toxic Substances and Disease Registry (ATSDR) has made slight changes in its conclusions in the October 2011 health consultation for Millsboro, DE, because of new guidance from the Environmental Protection Agency (EPA). The revised conclusion is that past exposure to trichloroethylene (TCE) in the Millsboro, DE drinking water between October 2004 and October 2005 may have increased residents’ likelihood of experiencing non-cancer health effects. The increased risk for cancer health effects is low.

Because the findings of the health consultation have changed, ATSDR is releasing the revised health consultation for another 30-day public comment period.

EPA had not yet completed its review of cancer and non-cancer health hazards for swallowing or inhaling TCE when ATSDR released the public comment version of the Millsboro water system health consultation on October 25, 2011.  EPA’s finalized review revises non-cancer and cancer health values. Using these revised guidelines, ATSDR re-evaluated potential exposures at the site.

In October 2005, the Town of Millsboro discovered TCE contamination in the water system. Residents were ordered not to use water from the system. The Millsboro Water Treatment Facility installed a granulated activated carbon filtration system to remove TCE before water enters the distribution system. In December 2005, testing revealed that filtered water met drinking water standards for TCE and was safe to use. Since the filters were installed, the water treatment facility has conducted weekly sampling to ensure that levels of TCE remain safe.

TCE was released into the soil from a refrigeration system in a poultry vaccine manufacturing plant, contaminating both the soil and, subsequently, the groundwater. TCE contaminated two of the three Millsboro water system wells between water tests in October 2004 and October 2005, possibly for as much as one year. ATSDR estimated past exposures and possible health effects by using pre-filtered well water test results taken between October 2005 and October 2006.

Based on the new guidance, ATSDR revised its conclusions to state:

  • Using Millsboro’s public water supply now or in the future will not harm people’s health, provided the water continues to meet federal standards and ATSDR’s health-based guidelines.
  • Past exposure to TCE in the public water supply may have increased the likelihood of Millsboro residents experiencing non-cancer health effects. The increased risk for cancer health effects is low.

To read the updated health consultation, go to

A copy of the health consultation is also available at the Millsboro Public Library and can be reviewed during regular business hours at the following location:

Millsboro Public Library
217 W. State Street
Millsboro, DE 19966

ATSDR will accept public comments on the document until September 17, 2012.

Comments on the health consultation must be made in writing. Comments received during the public comment period (without the names of persons who submitted them) and ATSDR’s responses to them will appear in an appendix to the final health consultation. Names of those who submit comments will be subject to release in answer to requests made under the U.S. Freedom of Information Act (FOIA).

Send comments to:, or mail to:

ATSDR Records Center
Attn: Rolanda Morrison
re: Millsboro Water Contamination Site
4770 Buford Highway, NE (MS F-09)
Atlanta, Georgia 30341

For more information about the health consultation, community members can contact Rob Robinson, Environmental Health Scientist, in Atlanta at or 770-488-3334 or by calling 1-800-CDC-INFO.

ATSDR, a federal public health agency of the U.S. Department of Health and Human Services, evaluates the human health effects of exposure to hazardous substances.

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Related News Releases For Sussex County, Millsboro, Delaware


ATSDR Releases Health Consultation on TCE Exposure for Millsboro, DE
Release Date: Wednesday, February 13, 2013
“Exposure to trichloroethylene (TCE) in the Millsboro, DE, drinking water between October 2004 and October 2005 may have increased residents’ likelihood of experiencing non-cancer health effects,” says the Agency for Toxic Substances and Disease Registry (ATSDR) in a health consultation released today.

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