4. Tansitor Electronics, Inc.

State: VT

Site Lead: State

Date Deleted from NPL: September 29, 1999

Date of Last Five-Year Review: September 23, 2009

COCs: VOCs

RAOs: 1,1,1-TCA less than 200 µg/L, 1,1-DCE less than 7 µg/L, TCE less than 5 µg/L, PCE less than 5 µg/L, which are the federal MCLs. A technical impracticability (TI) waiver was granted for a 10-acre area where MCLs do not have to be met.

Technologies Applied: Groundwater monitoring and monitored natural attenuation

Reported Results: Groundwater monitoring within the TI Zone has shown gradual reductions in concentrations of contaminants. Groundwater monitoring beneath and outside the TI Zone has demonstrated that there continues to be no migration beyond the TI Zone or the Site.

MCLs Achieved? No, because a TI zone was established.

ICs in Place? Yes, the use of groundwater is prevented through deed restrictions

Vapor Intrusion: With respect to potential vapor intrusion within the manufacturing building, information provided by the facility indicates that the HVAC systems create an ongoing air exchange of 8–24 times per workday to address the use of solvents within the manufacturing process and soil vapor data levels were below OSHA time weighted average levels. As the contaminated groundwater is a potential vapor intrusion source, EPA will continue to evaluate this pathway in future reviews, particularly if land use of the Site changes.

Long-Term Monitoring? Yes

 



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