TIVERTON -- New England Gas Co. has some explaining to do about its reports on its investigation into soil contamination in North Tiverton, the state Department of Environmental Management says in its long-awaited official response, released yesterday.
The DEM criticizes the soil-sample collection and testing methods used by the engineering firm hired by the gas company, Vanasse Hangen Brustlin.
The DEM also disagrees with many of the conclusions and decisions made by the gas company after Vanasse's reports were released late last year. The state Department of Health and federal Environmental Protection Agency have raised similar concerns, which were included in the DEM report.
The DEM did not know that the gas company "was intending on eliminating properties or drawing final conclusions based solely on this limited investigation," the document reads. "New England Gas Co. is reminded that [the DEM] originally wanted to investigate the entire neighborhood [about 150 properties] including the vacant property to the south of Judson Street."
Fall River Gas Co., which Southern Union bought three years ago, may have used the area as a dumping spot in the 1960s for hazardous waste from its coal gasification plant, the DEM said last March. Southern Union is the parent company of New England Gas.
New England Gas hired Vanasse when the DEM ordered the testing of 75 properties for soil contamination. Reports of Vanasse's findings were released in November and December.
Although several properties showed levels of contaminants above state standards, Vanasse's report concluded that most did not need further testing. It also said some of the contaminants found could have come from lead paint and pesticides, rather than from manufactured gas plant waste.
The Vanasse reports also said nine properties should be excluded from further testing by the gas company because contamination on those properties could be associated with previous business use on the land.
A separate report completed by a risk assessment firm hired by the gas company said "Activities such as walking and playing, gardening, ingesting home vegetables or digging a subsurface structure should not have a significant impact on human health from exposure to constituents in the soil," which contradicts what the state Department of Health has told residents since the contamination was discovered in August 2002.
Some of the points the DEM made in its lengthy report are:
"The department does not concur with New England Gas Company that the [Vanasse report] is complete on some if not all of the properties that were investigated.... The department requests that the proposed second phase of investigation look more thoroughly at all of the properties."
The nine properties are not "completely separate and distinguishable sites from this investigation due to historical ownership and commercial activities. There is evidence that some of the contaminants of potential concern may have originated" from the former gas plant. Therefore, it will not issue letters of responsibility to current or past owners "at this time."
Of the nine properties, "it should be noted that even if [the John Simpson Construction Co.] operated on [some of] these properties, the former Fall River Manufactured Gas Plant still has some liability if the waste material came from that facility."
The Vanasse report does not historically document anything about the Fall River Gas Plant, which is important for the investigation.
Observations made by Vanasse field testers were similar to those found at other manufactured gas plant facilities -- such as high iron staining, sulfur odor, blue or orange staining, gray or black coloration, clay and ash. "How did [Vanasse and the gas company] make the determination that none of their observations were not evidence of [manufactured gas] waste?"
The gas company does not provide support that high lead concentration might have come from other lead sources such as lead paint. Was there testing "performed along the drip edges of older homes or visual evidence of lead paint chips to support any assumptions?"
The gas company did not collect an "adequate representation of samples."
Several properties not suggested by Vanasse for further testing -- such as five lots west of the Bay Street playground -- "warrant further testing" because of the contaminants found in the initial investigation, the DEM concluded.
Alisha A. Pina can be reached by phone at 253-1200 or by e-mail at apina(at)projo.com.
