Toxic levels of PCBs have been detected at another elementary school.
Environmental Protection Agency inspectors found 18 out of 28 samples taken at P.S. 11 in Brooklyn showed PCBs above the regulatory limit of 50 parts per million.
EPA officials say the chemicals are leaking from old fluorescent light fixtures. The Department of Education says any fixtures found to be leaking will be removed.
Inspectors found PCB contamination at a Staten Island school earlier this month.
The chemicals were widely used in construction from the 1950s though the 1970s.
Health officials say that while the contamination does not pose an immediate health threat, long-term exposure can cause cancer and other health problems.