All four people aboard a small jet were killed Thursday morning when it crashed shortly after taking off from a small airport in Connecticut, officials said.

The jet took off just before 10 a.m. from the Robertson Airport before crashing into the building at Trumpf Inc., a manufacturing company, Farmington Police Lt. Tim McKenzie said.

“It appears there was some type of mechanical failure during the takeoff sequence that resulted in the crash behind us,” he said.

The plane, a Cessna Citation 560X, was headed to Dare County Regional Airport in Manteo, N.C., the Federal Aviation Administration said. Two pilots and two passengers aboard the plane were killed, McKenzie said. Their names were not immediately released.

The crash set off chemical fires inside the Trumpf building, Gov. Ned Lamont said. Everybody who was inside the Trumpf building has been accounted for and there were no serious injuries, McKenzie said

Lamont said authorities were in the process of identifying those who died on the plane. He said there was nothing left of it when first responders arrived.

“It was just a ball of fire, an explosion, and then the chemical fires afterwards," he said.

“I think they are still trying to identify who was there, identify the next of kin before we can say anything else. I just know it was incredible. The thing was filled with jet fuel."

Farmington is in central Connecticut, about 10 miles southwest of the state capital of Hartford.

McKenzie said an intense fire burned for over 20 minutes.

Caleb Vaichaus, who works near the crash site, said he ran to the scene after hearing a loud explosion and seeing billows of black smoke from the Trumpf building.

“I ran straight toward it to see if I could help. I got as close as I possibly could and the flames were extremely hot and the fire was just getting bigger," he told WTIC-TV.