The New Haven Coliseum, an arena that was once a center of activity in New Haven’s downtown, is on schedule to be demolished sometime early this fall, said New Haven Deputy Economic Development Director Tony Bialecki, although an exact date for the demolition will not be known for a few more weeks.

The prime contractor, Standard Demolition of Trumbull, Conn., is currently working inside the steel-and-concrete Coliseum and the nearby abandoned Macy’s and Malley’s department stores to remove as much of each structure as possible before imploding each building’s remaining superstructure.

“They’re … inside both buildings doing environmental remediation, and from there they will move outside on both buildings, and we can demolish them once they’re clean inside,” Bialecki said. “It’s more prudent to sort of go slowly, carefully with this thing.”

Before demolition work could begin, the Coliseum had to be disconnected from its electric power supply, a complex process which took a significant amount of time. Al Carbone, a spokesman for United Illuminating, the electric company working to disconnect the Coliseum from the city’s grid, said safety processes and extra cautions taken not to disrupt the rest of the grid caused the disconnect to take a few weeks.

Still, Carbone and Bialecki said, the complexity of the disconnect was anticipated, and there was no delay in the overall demolition process.

Bialecki said that a final date for the implosion will not be set for another few weeks. Once the date is set, rescheduling would be difficult because of the necessary safety precautions, which will require the assistance of police and fire services.

“Once they get that date, they’ll stick to that date, because there are whole procedures and plans,” Bialecki said. “They’re just trying to make sure that they have the right date.”