When the city Department of Housing Preservation and Development (HPD) abandoned its offices at 150 William St. in 1996, it was amid asbestos and lead problems. Now the Administration for Children’s Services (ACS) is set to move into the same privately-owned building.

But the union representing ACS’ social workers, the Social Service Employees Union Local 371, objects and is in arbitration to fight an entirely new crop of potential hazards.

Towards the end of HPD’s troubled seven-year tenancy on William St., union safety officials found asbestos on exposed radiator covers and in floor tiles, and a high percentage of lead in the paint, all of which has since been removed. These days, union officials are worrying about the elevators and the wiring. ACS isn’t set to complete its move from its current headquarters at 80 Lafayette St. until early fall, but some caseworkers have occupied part of the new building since 1996.

In recent months, some of those workers had to evacuate two floors temporarily due to smoke coming from the wiring, said Faye Moore, head of grievances at the union. And elevator troubles have been more persistent than at its current headquarters, notorious for elevators that stop and drop between floors. “You have people getting stuck on the elevator,” said Moore of 150 William St.

The agency has acknowledged these problems and says that the building’s owner, 150 William Street Association, will fix them. To be on the safe side, local 371 plans to inspect the offices within the next two weeks. If the union is still not satisfied with the elevators and wiring, it will resume arbitration, Moore said. “We will not let the other parts of ACS move in until we do a walk-through.”