Emergency workers on the scene of a fatal explosion in Hastings-on-Hudson. (credit: CBS2)

HASTINGS-ON-HUDSON, N.Y. (CBSNewYork/AP) – An old fuel tank exploded Thursday as it was being excavated from behind a home in Hastings-on-Hudson, shooting flames in the sky and leaving two men dead.

The blast took place around 11:30 a.m. at 65 Hillside Ave., according to Hastings-on-Hudson police. The two victims, identified as Segundo Mora, 50, and Luis Jocho, 52. were excavating the old fuel tank from behind the house when it exploded, WCBS 880’s Sean Adams reported.

Chief Anthony Visalli said Friday that investigators suspect that gasoline vapors in the underground tank – not the usual remnants of heating oil – caused the deadly blast.

Visalli said soil tests should reveal what the tank held. Hazardous materials experts and the state Department of Environmental Conservation were back at the scene Friday, he said.

“We believe the explosion was caused by gasoline vapor in the tank,” Visalli said. “We think it’s been there for a long time. Why there was gasoline we don’t know. That’ll all come out in the days and weeks to come.”

As CBS2’s Meg Baker reported, the explosion also put a Westchester County school on lockdown.

“The explosion of the tank went straight up about 75 feet in the air,” Westchester County Executive Rob Astorino said.