Nearly 30 years after the W.R. Grace & Co. property in Acton and Concord was designated as a national Superfund hazardous-waste site, environmental officials have removed all contaminated sediment and constructed new ground-water treatment systems.
The US Environmental Protection Agency recently announced it has finished its construction work at the site, but will continue to monitor activity there for the foreseeable future.
“We’re finally coming to the end of the race,’’ said Doug Halley, Acton’s health director, who has worked on the project since 1978. “The hard part, the hills, are behind us.’’
The EPA will conduct five-year reviews, continue the operation and maintenance of the ground-water treatment systems, and monitor the restored wetland areas and ground water.
Through treatment systems, contaminated ground water is being pumped out, treated, and put back underground, Halley said. He said the process will continue as officials monitor contamination levels. When contamination is no longer evident, the pumping will stop and the water tested to see whether it remains clear. If not, the pumping and treatment operation will continue, he said.
“Now we have certainty as to the action being taken,’’ Halley said.
A spokesman for W.R. Grace did not return calls seeking comment.
The former W.R. Grace chemical-manufacturing site off Independence Road in Acton includes several bodies of water and various wetlands. The approximately 260-acre property, which extends into Concord, was used for industrial purposes for more than a century. Halley said almost all of the contamination took place on the Acton portion.
While remediation continues in Acton, Concord is in the process of purchasing about 80 acres from W.R. Grace, said Town Manager Chris Whelan, after Town Meeting in the spring voted to spend $1.2 million to acquire the land. Whelan said the town would like to place solar panels on the property and may build a waste-water treatment plant there.
Robert Eisengrein, a former Acton resident who was involved in the cleanup efforts several years ago, said he’s pleased that federal, state, and local officials have been able to make so much progress.
“A lot of people should be commended, including W.R. Grace, which has supported this and didn’t just walk away,’’ said Eisengrein, who now lives in Devens.
Eisengrein, 92, lived in Acton about a mile from the site for about 10 years. He said his stepson used to play in the area and would talk about the multicolored puddles on the ground.
“It was scary at the time,’’ said Eisengrein, who estimated he attended hundreds of meetings on the issue. “A lot of people were concerned the water was polluted, but I drank it, and I’m still around at 92.’’
According to the EPA, W.R. Grace purchased the site in 1954 and manufactured materials used to make concrete and organic chemicals, container sealing compounds, latex products, and paper and plastic battery separators. Waste water and solid industrial wastes from these operations were put in several unlined lagoons, buried in a landfill or otherwise discarded on the property.
Investigations in 1978 indicated that two Acton municipal water-supply wells had been contaminated, and were shut down, Halley said. Following that discovery, W.R. Grace and the EPA entered into a cleanup agreement, and in 1983 the site was placed on the agency’s Superfund National Priorities List.
Halley said there was a six- or seven-year period when residents may have ingested contamination; however, officials have studied cancer rates and determined that there was no public health impact.
The EPA says between 1983 and 1997, numerous studies, risk assessments, and sampling events were conducted at the site, and led to the removal of more than 100,000 cubic yards of contaminated soil and sludge. All of the facility’s buildings, with the exception of those associated with the remedial action, have been demolished.
Grace also operated an aquifer restoration system that extracted and treated contaminated ground water on portions of the site from 1983 until last year; it was replaced by the current treatment systems.
Over the last two years, the EPA and the state Department of Environmental Protection conducted inspections at the site to ensure that the construction of the ground-water treatment systems and the sediment excavation and removal were in compliance.
Prior to W.R. Grace, the site was home to the American Cyanamid Co., which manufactured explosives, and the Dewey & Almy Chemical Co., which produced synthetic-rubber sealants, latex products, plasticizers, and resins.