The Board of Finance has approved $4.2 million in bonding to replace the windows at Osborn Hill School and remediate PCB contamination that was discovered at the school when the project was launched last year.

Testing done prior to replacing the old, inefficient windows at the Stillson Road elementary school led to discovery of the PCB contamination. Some of the potential carcinogenic substance was found in window caulking and paint, and some of it was airborne in the gymnasium as the result of spray-on fireproofing. The law now requires schools to test for PCBs, asbestos and lead when undertaking renovations.

"Once you test and find them, you have to remediate them," Superintendent of Schools David Title told the finance panel Tuesday. "For the windows, the cleanest more efficient way is to replace them."

The funding includes the $820,000 already expended by school officials over last summer to clean up PCBs in preparation for the start of the new academic year last fall.

The bonding request still must be approved by the Representative Town Meeting.

Title told the board that school officials expect that they will receive state reimbursement for about 25 percent for parts of the project.

If the windows and caulking are not replaced, he said, then "you are committing to an ongoing testing program" to prove to the federal Environmental Protection Agency that corrective measures are working on a quarterly basis.

Architect William Silver said out of the total money being sought, about $1 million is not connected to EPA requirements regarding the PCBs. That money is for the new windows themselves and Silver said their energy-efficiency value should pay back those costs in about seven to 10 years.

Finance Vice Chairman Robert Bellitto Jr. asked, especially with the impending renovation of Riverfield School, is the Osborn Hill window project still such a priority. "I'm just wondering what's going to be get bumped because we're doing all this," he said.

"In our opinion, this needs to be done now," Title said. "To me, this is very important." Silver said there is really no benefit to deferring the project.; 203-556-2771;