GROTON -- It has often been reported that there was a light at the end of the tunnel regarding cleanup efforts at a former industrial property near the center of town, but after a recent meeting with the town's Conductorlab Oversight Committee, that light might finally appear.
According to representatives of the Honeywell Corp. who briefed the committee Tuesday, latest testing confirmed that harmful chemicals at the company's 430 Main St. site are below dangerous levels and plans were being made to demolish an existing building on the property.
"We are very hopeful that we continue to get good data over the next three quarters," Honeywell remediation manager Maria Kaouris told committee members.
Kaouris said four consecutive quarters of testing with traces of organic solvents called trichloroethene, or TCE, within acceptable limits must be registered before the property can pass rigorous federal and state safety standards.
Already, said Kaouris, one quarter has met the standard with three more to go over the course of 2014.
Should safety levels be maintained over those quarters, a risk assessment of the property would be conducted and submitted to the state for approval followed by demolition of the building and eventual disposition of the property.
Contaminants in the ground at the Main Street site included metals (hexavalent chromium) and TCEs that were used as degreasers in the manufacture and later treatment and disposal of circuit boards.
Most of the contamination on the property has been located in an area formerly used for wastewater treatment and its disposal in a leaching bed called by Honeywell cleanup officials as the "hot spot."
The residual contaminants in the soil are all that is left of a company called Conductorlab, which opened the manufacturing facility in 1958 and remained in operation at the 3.2-acre site until closing in 1985.
Since then, only the groundwater and treatment system have been in operation with such Honeywell subsidiaries as Grimes Aerospace performing monitoring duties at the site, which have included the installation of groundwater monitoring wells on and off the property, water and soil sampling, and indoor air-quality testing.
That situation was altered with the introduction of oxidizing chemicals made of iron and sodium persulfates which were leached into the underlying bedrock beneath the property.
Those efforts, reported Kaouris, have apparently succeeded rendering the contaminants inert to the point where they were "essentially gone."
Assuming that the site will be found clean, Kaouris said that the existing building there would be razed in 2015 with each piece inspected for further contamination and safely disposed, cleaned or recycled.
At that point, said Kaouris, Honeywell would conduct talks with the town to decide what to do with the property -- either sell it on the private market with a use-limitation rider or use it for municipal purposes.
Honeywell will remain responsible for the site should any questions regarding contamination arise in the future.
Members decided to doublecheck Honeywell's work by hiring an independent company to peer review its claims.