PORTLAND – A two-year program designed to get mercury out of Maine schools has uncovered stockpiles of potentially dangerous chemicals that could cost millions to clean up, state environmental officials said.

So far, 6,500 pounds and more than 1,000 gallons of hazardous waste have been removed from science labs, maintenance departments, art and vocational classrooms, and nurses’ stations in about 80 Maine schools.

More than 700 pounds of mercury have been removed from schools, making them the second-largest source in the state. Only the defunct HoltraChem chemical plant in Orrington has a larger mercury stockpile.

The clean-out program, run by the Maine Department of Environmental Protection, has also discovered radioactive materials in more than a dozen schools and shock-sensitive chemicals that have deteriorated and could explode if moved.

Ann Pistell, who coordinated the program for the environmental department until it ran out of funding this year, recalled finding a container in one school that “could have blown up the classroom” if someone took it from its shelf.

Among the most disturbing findings were bottles of bromine and chlorine, both used to make mustard gas, that were tucked away in several schools, Pistell said.

Had one of the bottles developed a slow leak, it could have killed “instantly a substantial number of people in the school,” she said.

The state sponsored a limited school chemical clean-out in the 1990s, but the program was voluntary and did not include training for teachers. This project, which involved about 18 percent of Maine’s schools, show there’s still work to do.

Last year, the state included $500,000 in an environmental bond issue to help a systemwide cleanup. The bond failed, but the environmental department plans to try again this year with another bond issue or a specialized fee.

“We will come up with a funding source somehow for this,” said Dawn Gallagher, the department’s environmental commissioner.

But Gallagher said chemical clean-outs at every school will likely cost much more than $500,000. “That’s only a beginning, frankly,” she said. “I think it’s going to be several million dollars.”

Jon Hinck, toxics project director for the Natural Resources Council of Maine, said that seeing the results of the DEP’s school mercury project “opened our eyes to a pressing issue.”

Hinck said what Pistell found in the schools she has helped so far shows “that this really shouldn’t be left to languish as we sometimes do with policy matters.”

The Natural Resources Council of Maine has decided to take up the issue immediately and talk to legislators. The group also plans to do some direct outreach to schools to teach faculty and students about chemical hazards.