The W.R. Grace (Acton Plant) site is in Acton and Concord, Massachusetts. In 1954 W.R. Grace & Company purchased the property and began producing container sealing compounds, latex products, and paper and plastic battery separators. Effluent wastes from these operations flowed into several unlined lagoons and were later buried in onsite waste areas, including an industrial landfill. After a 1978 investigation revealed that ground water in the vicinity of the site was contaminated with VOCs, W.R. Grace & Company agreed to fully restore the aquifer. An aquifer restoration system was installed in 1985 which recovers and treats ground water under the site's waste disposal areas. Subsequent samplings, however, have indicated that the system has only minimally reduced the ground water contamination at the site. This first operable unit primarily addressed the source contamination and includes minimal modifications to the aquifer restoration system. Further ground water remediation will be addressed in a subsequent Record of Decision. The primary contaminants of concern affecting the soil, sediment, and sludge are VOCs including benzene and toluene, other organics, and metals including arsenic.