The Agency for Toxic Substances and Disease Registry (ATSDR), a public health agency of the U.S. Department of Health and Human Services, today is issuing the final public health assessment (PHA) for the Lockwood Solvents Groundwater Plume Site in Billings, Mont. The PHA reports that certain adverse health effects might have been experienced by residents in the affected area.

The Lockwood Solvents Site is a chlorinated solvent groundwater plume containing tetrachloroethene (PCE), trichloroethene (TCE), cis-1,2-dichloroethene (cis-1,2-DCE), and vinyl chloride. The site is in the unincorporated community of Lockwood, adjacent to the northeastern outskirts of Billings.

Sampling data show that volatile organic compounds (VOCs) have entered private wells at levels above federal and state drinking water standards. People in the area used their private wells for domestic purposes, including showering and bathing.

ATSDR reaches the following conclusions in the PHA:

• Before area residents switched to a municipal water supply, some residents were exposed to volatile organic compounds (VOCs) that might have caused harmful health effects. Residents were exposed to VOCs in groundwater while bathing or showering or other domestic uses. Such contact resulted in inhalation exposure as the VOCs evaporated from the water into the indoor air and in dermal exposure by absorption through the skin.
  • A few residents thus were exposed to tetrachloroethene (PCE), which might have damaged their nervous system. Specifically, that exposure to PCE might have caused mild changes in eye-hand coordination, changes in the ability to respond as quickly as normal to repeated stimuli and changes in the eye's perception of stimuli.
  • Residents who showered with water from wells with high PCE levels might have an increased risk of cancer from PCE exposure. This conclusion is uncertain because of limitations in determining the risk of cancer from PCE exposure.
  • A few residents also were exposed to vinyl chloride, which might have increased their risk of cancer.
• Some adults and children might have been exposed to VOCs via a soil-gas pathway, that is, by inhaling indoor vapors that leached from the soil.
• To date, all of the affected homes either receive water from the municipal water supply or are served by wells in which any contamination is below drinking water standards.
• The soil-gas pathway and outdoor use of contaminated private wells remain potential exposure pathways for residents whose homes are connected to the public water supply.

The source and extent of the groundwater contamination has not been determined. Sampling data indicate that contaminant levels are approaching maximum contaminant levels (MCLs) in several private wells in the site area and off-site wells could become contaminated as the plume migrates; therefore, monitoring of the contaminant plume is necessary to prevent future exposures to adults and children.

ATSDR recommends the following for the Lockwood Solvents Site:

• Implement procedures to stop exposure to contaminants in groundwater if private wells exceed state or federal guidelines.
• Define the extent of the contaminant plume to determine whether other private wells in proximity to the plume have been affected or could in the future be affected.
• Continue to monitor contaminant levels in private wells of area residences and commercial businesses that are not connected to the public water supply.

The Montana Department of Environmental Quality has completed an earlier recommendation from ATSDR to monitor indoor air concentrations at selected residences.

ATSDR previously encouraged residents to contact their personal physicians if the residents' wells contained high levels of VOCs.

The PHA is available at the following repositories:

Montana State University-Billings Library
1500 North 30th Street
Billings, MT

Montana Department of Environmental Quality
Remediation Division
209 Phoenix Avenue
Helena, MT

U.S. Environmental Protection Agency, Region VIII
Montana Operations Office
Federal Building
301 South Park, Drawer 10096
Helena, MT

Community members seeking information on the procedures or the content of the public health assessment may contact Environmental Health Scientist Teresa Foster toll free or Health Communications Specialist Debra Joseph at 1-888-422-8737. Regional Representative Dan Strausbaugh also may be contacted at 406-457-5007 or 303-717-2952. Callers should refer to the Lockwood Solvents Site in Billings, Mont.