SYRACUSE, N.Y. — An excavator caught fire Monday afternoon as crews worked to remove debris of St. Joseph’s Hospital Health Center’s demolished human resources building in Syracuse, officials said.

Syracuse firefighters spent about 40 minutes battling the flames. At one point, as the flames and black smoke intensified, a large “boom” could be heard around the construction site on Hickory Street at Prospect Avenue.

Syracuse police blocked part of Prospect Avenue and stood with construction workers while firefighters battle the blaze. The Syracuse Fire Department’s Hazardous Materials Unit responded because there was a large quantity of diesel fuel and hydraulic fluid, Syracuse Deputy Fire Chief Steve Cavuto said.

After talking to the subcontractor, the deputy fire chief said the crew thought oil may have sprayed onto the hot engine, causing the fire.

Later, the construction manager confirmed the problem: The turbo in the motor of the excavator engine burst, igniting the fire, said Gary Thurston, chairman of The Hayner Hoyt Corp.

St. Joseph’s Hospital Health Center has a $400,000 contract with The Hayner Hoyt Corp. of Syracuse to demolish the former human resources building and turn it into a parking lot at 410 Hickory St., St. Joe’s project engineer Ed Grabowski said. A broken pipe damaged the building last year; hospital officials decided to tear it down and create more parking, Grabowski said.

The excavator was destroyed in the fire. Work will continue after the charred machine is removed and replaced with another excavator, Thurston said. The construction project is expected to be completed by June, he said.