TCE Levels At Richmond Deemed Safe
But Hanover School Officials Say More Tests Still To Be Conducted
Hanover — Even though test results for trichloroethylene inside the Richmond Middle School have shown safe levels of the chemical compound, school officials are adamant that more testing will be done.
The U.S. Army Corps of Engineers received results yesterday of testing it did April 1 to determine if TCE, which is a known carcinogen, was present in the air inside the middle school. The results, shared with school officials yesterday, showed that TCE ranged from non-detectable levels to 1.2 micrograms per cubic meter in the air. What was found in the middle school is below the New Hampshire Department of Environmental Services screening level in commercial buildings for TCE, which is 1.8 micrograms per cubic meter.
When a chemical compound reaches a screening level, a cleanup is not ordered but it does trigger additional investigation. In the case of Richmond Middle School, additional testing is still being conducted but no mitigation will be ordered at this time, said Darrell Moore, a project manager for the U.S. Army Corps of Engineers New England district.
Last month, the Corps of Engineers announced that it would be widening its search for TCE from the campus of the Cold Regions Research and Engineering Laboratory on Route 10 to adjacent properties. Richmond Middle School is across the street from CRREL and it is the first adjacent property to receive results. More results are expected this week for neighboring Brendel & Fisher Wealth Management and the building that houses Hanover Family Chiropractic and Hanover Yoga. Five houses to the south of CRREL in the Fletcher-Cedar neighborhood were also tested and those results should be in next week, Moore said.
“Even though this first batch of testing is encouraging, we still have a long way to go to make sure our students and staff aren’t in danger from TCE contamination,” Superintendent Frank Bass said. “It doesn’t mean that there is absolutely no TCE on the property.”
TCE was used as a refrigerant at CRREL from 1960 to 1987 and during that time it frequently spilled. In May 1970, a blown gasket caused 6,000 gallons of TCE to be moved to a storage tank, but many gallons went through the floor drains and into the sewer system. And then in July 1970, a tank exploded and about 3,000 gallons of TCE leaked and much was washed down the sewer system.
At the time, the hazards of TCE were not known, but scientists and environmental officials now know that TCE can cause damage to the central nervous system and immune system and cause cancer.
Officials have been investigating and cleaning up TCE at CREEL since 1990, but only in 2010 did they realize that vapor intrusion was an issue. Vapor intrusion can occur inside buildings when chemicals like TCE are in soil, soil gas or groundwater. The chemicals inside the soil or groundwater can then enter the building from beneath the concrete slab and become trapped, allowing people to breathe in the chemicals.
The levels that were found at the middle school are low enough that they don’t prove that the TCE entered the building through vapor intrusion, Moore said. The Corps of Engineers also tested the ambient air outside of the middle school and found non-detectable levels to 0.91 micrograms per cubic meter of TCE, which is just below the 1.2 micrograms per cubic meter that were found inside the building.
In the sub-slab soil, as much as 1.1 micrograms per cubic meter of TCE was found. If the TCE entered the building through vapor intrusion, then the soil vapor would likely be at a higher level than the air inside the building, Moore said.
“It’s nothing to worry about at this time. They are very low levels,” Moore said.
Officials with the Corps of Engineers first notified school administrators and neighbors about the expanded testing in early March. School administrators learned that it could be nearly a month before tests could be done by the Corps of Engineers, so school administrators hired their own consultant to conduct initial testing. While the tests were limited, the only TCE that was found in the building was in the principal’s office, and it was such a low level that it didn’t cause concern.
Dartmouth College did a similar round of testing with a private consultant within the 32 homes in the Fletcher-Cedar neighborhood, which is just south of CRREL and is home to Dartmouth employees.
Dartmouth raised initial alarms in late March when it announced that TCE was found near or above the screening level for a residential property in a vacant house near the CRREL property line.
Dartmouth originally only tested three homes, then expanded its own testing to include all 32 Fletcher-Cedar homes. As of last Thursday, results for 19 homes had come in, and no additional TCE was found in any of the homes. However, benzene, carbon tetrachloride and chloroform have been found in numerous homes. Dartmouth spokesperson Justin Anderson said the college is investigating the source of the additional chemical compounds.
The Corps of Engineers has tested five homes near the CRREL property line and those results are expected to be in next week, Moore said.
The Richmond Middle School results will be shared with the Department of Environmental Services, as well as the school district’s consultant, Haley and Aldrich.
The Corps of Engineers and its contractor, AMEC, will continue testing at the Richmond this week by drilling into the ground outside the school and taking samples at 10, 25, 50 and 75 feet, Moore said. Another round of sampling will be done in July or August.
Bass, the superintendent, stressed that the air inside the middle school is safe and that yesterday’s test results were encouraging, but said he and other school administrators will be taking a “cautious approach” in the months ahead.
“We have to proceed very cautiously here, and I don’t want to indicate that we’re all set because we’re not,” Bass said.
Sarah Brubeck can be reached at firstname.lastname@example.org or 603-727-3223.