A toxic Gloucester County day-care building - where children once breathed mercury vapors - was demolished yesterday, ending an embarrassing chapter in New Jersey's struggle to manage thousands of contaminated sites.

The steel claws of a track excavator took less than three hours to rip apart the former Kiddie Kollege and pile the debris in the basement and on the edges of the Franklinville site.

A sign that read "Warning: Inhalation Danger" lay crumpled and twisted in the rubble, a symbol of the missteps that allowed about 100 babies and children to be exposed between 2004 and 2006 to dangerous levels of mercury.

A thermometer factory previously occupied the building, and when it went bankrupt, the bank that held the deed wanted such a warning sign to be posted. It isn't clear whether it was erected before a Realtor acquired the building in a tax foreclosure and leased it to the day care.

Mercury vapors can cause brain and kidney ailments. After a state Department of Environmental Protection inspector discovered the day-care center in the contaminated building, it was closed, and the now-crumpled sign went up.

The contaminated rubble will be carted away over the next few weeks, Dennis Faherty, DEP's construction manager, said at the site yesterday. Roughly 700 tons will be trucked to a toxic-disposal site in Indianapolis.

"We took air readings inside the building today, and it was zero for mercury," Faherty said. Previously, the DEP detected mercury levels inside the one-story cinder-block building at 27 times acceptable standards.

Faherty said the cold weather likely kept the mercury from vaporizing yesterday, and added that workers had discovered "a couple of thimblefuls of free mercury" in the ceiling joists of the basement.

A tank truck supplied water that was sprayed on the debris to keep down the dust. A discarded hot-water tank and pipes were among the red cinder blocks piled up on the site, which is adjacent to the Jim Sullivan Real Estate office on Delsea Drive.

Jim Sullivan III had acquired the building and rented it to the day-care center, saying he misread an environmental report and assumed it was safe. He was unavailable for comment yesterday; an office worker said he was vacationing in Myrtle Beach, S.C.

Nancy Hanson, who lives nearby, said she was relieved to see the razing. "I'm glad to be done with it all," she said, noting that the state had installed a special water filter in her house after testing her well water for mercury.

Dan Donnelly, who lives across the street from the site, also applauded the demolition. "It's got to be cleaned up," he said. "I don't like the idea of being so close to the mercury, the hazardous site."

The children's parents and former day-care staff are part of a lawsuit filed against Sullivan, the DEP, Franklin Township, and others to pay for medical monitoring. No trial date has been set.