Dartmouth is currently investigating levels of the carcinogen trichloroethylene, or TCE, in the Fletcher-Cedar neighborhood, a College-owned property adjacent to the U.S. Army Cold Regions Research and Engineering Laboratory, which consists of 32 residences about a mile away from campus. The chemical may have migrated to some of the buildings from CRREL.
The College, along with the other neighboring property owners, was informed last month that TCE vapor might have extended outside the borders of CRREL property into the Fletcher-Cedar residences. CRREL representatives asked the College and the Richmond Middle School, among other properties nearby, for permission to perform tests on the properties.
CRREL plans to test the five houses closest to its boundary, which it believes are the most likely to be affected. The College will also conduct its own research on all of the houses, media relations director Justin Anderson said.
Less than two weeks ago, the College conducted its first of multiple tests on three vacant Fletcher-Cedar residences adjacent to CRREL, according to Anderson.
"We initially conducted testing on three vacant homes," Anderson said. "On Thursday night, we learned from this testing that TCE was present at levels at or above the screening level in the basement of one of the houses."
The screening level marks the threshold at which the state mandates further investigation. Anderson said the level does not indicate that cleanup is needed, nor does it suggest that there is a threat of potential harm to humans.
On Monday, the College revealed that tests of two other residences did not indicate any TCE presence.
The areas under concern are only those in CRREL's immediate vicinity, and Dartmouth has offered to provide temporary relocation to residents who request it until the College installs a sub-slab depressurization system, which remediates the air quality. The sub-slab depressurization system is the same system installed in the CRREL facility.
"There is no reason for Dartmouth students to be concerned," Anderson said.
Residents in the Fletcher-Cedar community were first informed of the testing in a March 26 letter, which detailed possible TCE migration and described the College's planned precautions.
After the College received confirmation of TCE screening levels in the basement of a vacant residence, it sent out a second letter on March 29.
"We understand that hearing this information is somewhat unsettling," Anderson said. "Our primary concern is to take care of those residents."
Fletcher-Cedar residents attended an information session hosted by the College last Friday, which featured representatives from the Dartmouth Real Estate Office and Dartmouth's Environmental health and safety group, among others.
Although the CRREL's initial testing did not indicate the presence of TCE at Richmond Middle School, a second test performed by an environmental consultant hired by Richmond Middle School indicated levels of TCE well below the most conservative screening levels, school principal Jim Nourse said.
Richmond Middle School will host an open house to discuss TCE levels tonight. Representatives from the Army Corps of Engineers will answer questions and provide more information about TCE, Nourse said.
On March 26, the middle school held a staff meeting and later sent an information packet to all school district parents. Nourse said that the school is handling the situation with care in order to ensure student safety.
"We are taking this seriously, and there will be continued monitoring of it," he said.
Norse said he has not received any emails or complaints from concerned parents or faculty. CRREL has been conducting its own research on TCE vapor that may have migrated beyond the facility, said Scott Hilton, Department of Environmental Services project manager.
"We found it at elevated levels at the property line," Hilton said.
The first round of the off-site vapor intrusion investigation began yesterday and is expected to be completed by April 15, Hilton said. The investigation will involve recording levels found in indoor air, outdoor air and in the soil below the investigated structure's foundation slab.
"There may be follow-up work after this first phase in the investigation depending on the findings," Hilton said. "Typically, you do two rounds of vapor testing to see if there are changes in concentrations in time."
CRREL previously used TCE as a refrigerant until 1987. The substance leaked in the early 1970s to mid-1980s, and in 2010, preliminary tests on TCE indicated that TCE was in the air in certain areas.
In order to minimize exposure to TCE vapor, CRREL has installed air purification systems and sub-slab depressurization systems.
While the TCE presence at CRREL is still being monitored, levels are low.
In addition to the TCE vapors, past TCE spills have contaminated CRREL's groundwater and is in the process of being removed.
