LOUISVILLE, Ky. — A UPS cargo plane’s left wing caught fire and an engine fell off just before it crashed and exploded after takeoff in Kentucky, a federal official said Wednesday, offering the first investigative details about a disaster that killed at least 12 people, including a child.

First responders, meanwhile, searched for more victims, a day after the crash at UPS Worldport, the company’s global aviation hub in Louisville, though Gov. Andy Beshear said finding survivors seemed unlikely. The inferno consumed the enormous aircraft and spread to nearby businesses.

After being cleared for takeoff, a large fire developed in the left wing, said Todd Inman, a member of the National Transportation Safety Board, which is leading the investigation.

The plane gained enough altitude to clear the fence at the end of the runway before crashing just outside Louisville Muhammad Ali International Airport, Inman told reporters.

Airport security video “shows the left engine detaching from the wing during the takeoff roll,” he said.

The cockpit voice recorder and data recorder were recovered, and the engine was discovered on the airfield, Inman said.

“There are a lot of different parts of this airplane in a lot of different places,” he said, describing a debris field that stretched for half a mile.

The plane with three people aboard crashed about 5:15 p.m. Tuesday as it was departing for Honolulu from UPS Worldport at the Louisville airport.

The crash had a devastating ripple effect, striking and causing smaller explosions at Kentucky Petroleum Recycling and hitting an auto salvage yard, Grade A Auto Parts. Beshear said the child who died was with a parent at the parts business.

Beshear earlier said it was a “blessing” that the plane did not hit a nearby Ford Motor factory or the convention center.

U.S. Rep. Morgan McGarvey, D-Ky., praised firefighters who rushed headfirst to the disaster scene, describing it as “hotter than hell and raining down oil.”