Thursday, January 18, 2001 Older Editions

Radon mitigation for new schools

By Adam Groff

Saying they can't be sure whether there will be unsafe levels of radon in the two new schools under construction in West Andover, town officials have decided to equip the buildings with a radon mitigation system.

Eight of nine preliminary tests of the area where the new schools will be built indicate there are radon levels there well above Environmental Protection Agency standards. As a result, the School Building Committee, on the advice of the Health Department, has recommended that a special ventilation system be incorporated into the two new schools being built at Cross Street and High Plain Road. It is estimated to cost about $200,000.

Radon is a naturally occurring radioactive gas that can cause lung cancer. According to town project manager Phil Tuminelli, building on a rock ledge, like the one underlying the site for the new schools, can increase the risk of elevated radon levels.

"When you're blasting rock," he said, "you end up fracturing the rock, and radon can come up through the cracks. The problem with radon is that there's no way of telling whether you're definitely going to have radon."

He said that the presence of radon is difficult to detect before the walls and roof of a building are erected, creating an enclosed space in which the gas can collect. However, he said it is possible to conduct a rough test for radon by placing a detection kit under a basket, covering the basket with plastic sheeting, covering the sheeting with sand, and leaving it there for 48 hours. Tuminelli says that's what he and the construction engineers did.

"The tests came back positive," he said, while cautioning that such tests are not conclusive.

"It's always cheaper to address a radon problem preventively than after the fact," said Health Director Everett Penney, who agreed that there is no "proof positive" of a radon problem prior to substantially completing a construction project. He said his department brought the issue to the attention of the School Building Committee last year in the course of reviewing plans for the schools when the department saw the amount of ledge on the site.

Penney says radon is quite common in Andover.

"We had done a program in 1988 and '89 with residential homes where we made radon test equipment available to people," said Penney. He said participating Andover residents tested their own homes for radon and then submitted the tests anonymously for evaluation.

"About one third of them were above the (radon level) that the EPA recommends for health protection," said Penney. Radon is measured in picocuries per liter of air, or pCi/l; the safe level recommended by the Environmental Protection Agency is 4 pCi/l.

Penney said that eight of the nine tests conducted by Tuminelli and the construction engineers returned an average radon reading of about 200 pCi/l.

Regarding the seemingly high readings, Penney cautioned that there is no EPA-approved method for ground testing for radon; he said that the method used at the Andover school site is the one suggested by the state health department, and it is only a rough guide. However, he said, the tests gave enough of an indication of risk to warrant preventive measures.

"I would say that this site is no different from any other in Andover," said Penney, adding, "A radon problem is very easily cured or prevented by circulating air."

The mitigation system for the schools will consist basically of ventilating the space under the buildings.

Said Tuminelli, "What we're doing is we're putting in crushed stone and we're going to put in some piping and were going to have six to eight 'pressure points' to siphon the gas off." He said that the fans for the system will be left out until the buildings are erected and more accurate tests can be taken.

"We're doing the work now that we can't do 15 months from now if we do have a problem," he said.

The current rough estimate for the cost of the system is $200,000.

"We feel pretty good that the final number won't be that high," said School Building Committee Chairman Mark Johnson. He said the money for the system will come out of contingency funds.

"It's like insurance," said Penney of the system. "The chance you take is that if you don't do anything and you test on the first day of school and it's above the 4 (pCi/l), it could not only be more expensive, it could delay the opening of school."

The state Department of Public Health publishes a radon fact sheet that can be found online at www.state.ma.us/dph/rcp/radonfq.htm.