- Upgraded underground fuel storage systems were supposed
to prevent the gasoline additive MtBE, cited as a cancer threat, from leaking
into groundwater in New Hampshire.
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- Gary Lynn, chief of petroleum remediation for the New
Hampshire Department of Environmental Services, said the new double-walled,
double-piped tanks were "a liquid release success story (but) there
was an unrecognized problem . . . vapor releases" of methyl tertiary
butyl ether.
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- The vapor release problem was a topic of concern at a
groundwater contamination conference last week in Baltimore. Cliff Rothenstein,
director of the Environmental Protection Agency's Office of Underground
Storage Tanks, said: "We need to find out the source of the problem
and . . . make sure systems are both liquid- and vapor-tight."
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- Lynn said New Hampshire is already working on the problem.
He said DES got a heads up on the problem from California in 2002, when
extremely sensitive testing there showed there were still leaks at gas
stations; this time vapors were the problem.
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- Lynn said that solved a seeming mystery here. Despite
groundwater cleanup projects and installation of upgraded fuel storage
systems, the MtBE problem wasn't going away. In fact, he said: "Here
we are cleaning up the site and the MtBE (level) is going in the opposite
direction."
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- Lynn said the vapor leaks are small enough that they
aren't detected by normal testing, so the state had to hire the same vendor
who could do the extremely sensitive "tracer" testing used in
California.
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- The special testing confirmed the loss of MtBE vapor
from tanks at a Windham location, which is being used as a test site for
vapor containment solutions.
-
- Lynn praised the cooperation of Kevin Waterhouse, the
owner of the Waterhouse Country Store in Windham, saying: "The owner
has been a champ."
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- He said there is no simple solution to the vapor leak
problem. Not only do tanks systems have lots of connections, each a possible
source of leakage, but there are also underground, plastic lined sumps
that may only contain liquids, and above and in-ground vents that can get
stuck open.
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- Complicating the problem is that MtBE vapors are "very,
very water-soluble," he said.
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- That's evident because there is MtBE found at nearly
100 of the more than 400 gas stations where the DES does groundwater monitoring.
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- At the Waterhouse Country Store in Windham, Lynn said
the problem resulted from tanks that were pressurized slightly by recycled
gas vapors.
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- "We've reduced the pressure, to see if we can reduce
the release," he said.
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- "We're one of the early states," he said, in
identifying and tackling the vapor release problem. The state is now testing
a variety of potential solutions, including membranes, and has invited
the University of New Hampshire to join in trying to develop and test alternatives.
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- Lynn said new tank standards and the use of Stage 2 systems,
utilizing what Lynn called the "hoods" and "flying saucer"
on the gas dispensing nozzle to collect vapors and prevent their escape
can help with the vapor problem.
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- New Hampshire's ban on MtBE in gasoline, which goes into
effect in 2007, won't eliminate the MtBE problem, but he said: "The
vapor release problem will be a much smaller problem."
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- The Associated Press contributed to this report.
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- http://www.theunionleader.com/articles_showfast.html?article=42827
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