The Lockwood Solvent Ground Water Plume covers 580 acres near Billings, Montana. Workers discovered benzene and chlorinated solvents in local water supply wells in 1986. The EPA added the site to the Superfund National Priorities List in December 2000 and selected a cleanup plan in August 2005. Two companies caused the contamination: Beall Trailers of Montana, which cleaned tanker trucks with industrial solvents from 1978 to 1990, and Soco West (formerly Brenntag West Inc.), a chemical repackaging company operating since 1972.
The site contains four contaminants of concern: vinyl chloride, cis-1,2-dichloroethene, tetrachloroethene (also called PCE), and trichloroethene (also called TCE). All four have been found in groundwater. Three of the four also appear in soil, surface water, and air. These chemicals can pose long-term health risks through drinking, eating, bathing, and routine industrial contact. No one is currently known to be drinking the contaminated groundwater. All residents whose wells exceeded health standards received public or bottled water until 2016, and no drinking wells now exceed contamination limits.
The site is divided into three operable units, or OUs. At OU1 (the Beall area), the EPA demolished an old steam bay building, excavated contaminated soil, and installed a soil vapor extraction system. Remedial action at OU1 is estimated to begin between September and November 2028. At OU2 (the Soco West/Brenntag area), excavation of contaminated soils began in 2017. Over 60,000 cubic yards of soil were excavated and treated through 2021. Groundwater treatment at OU2 uses an ozone sparge system and vegetable oil injections to support natural breakdown of contaminants. Work at OU2 stopped in 2023 after Soco West's parent company filed for Chapter 11 bankruptcy. The EPA completed emergency removal work in November 2023 to cap and stabilize remaining soils and secure the property. Indoor air sampling in 2013 and 2021 found no vapor intrusion problems at either location.
Human exposure is currently considered under control, and groundwater migration is stabilized with no unacceptable discharge to surface water. Physical construction is not yet complete, and the site is not ready for its anticipated future use. Groundwater monitoring was suspended in 2023 but is expected to resume in 2025, with the EPA leading data collection. The Montana Department of Natural Resources and Conservation established a permanent controlled groundwater area, finalized September 25, 2018, to prevent new wells from tapping contaminated water. The next five-year site review is estimated between July and September 2027.
Community members can access site documents through a digital collection at the Montana State University library in Billings. The EPA also offers assistance to property owners near the plume who need help with refinancing or selling their properties. Residents with questions can contact the EPA's Community Involvement Coordinator or Remedial Project Manager.
