LOUISVILLE, Ky. — The painstaking search for victims following the catastrophic crash of a UPS cargo plane in Louisville, Kentucky, extended into its third day on Thursday. Investigators are diligently working to uncover the causes behind the aircraft’s fiery demise and engine failure during takeoff.

The blaze that engulfed the massive plane spread rapidly to nearby businesses, resulting in the tragic loss of at least 12 lives, including a child. This devastating event has left little hope of finding survivors amidst the wreckage at UPS Worldport, the pivotal global aviation hub for the company.

The ill-fated aircraft, carrying three crew members, had been cleared for takeoff on Tuesday when flames erupted from the left wing, explained Todd Inman from the National Transportation Safety Board. Although the board is spearheading the investigation, Inman noted that determining the exact cause of the fire and engine detachment could take over a year.

Despite the engine failure, the plane managed to gain enough altitude to clear the runway fence before crashing just beyond the Louisville Muhammad Ali International Airport, Inman reported. Investigators have since retrieved the cockpit voice recorder and flight data recorder, with the detached engine found on the airfield.

The crash’s explosive impact triggered secondary explosions at Kentucky Petroleum Recycling and damaged a nearby auto salvage yard. Tragically, the child who perished was at the salvage yard with a parent, according to Governor Andy Beshear.

Some people who heard the boom, saw the smoke and smelled burning fuel were still stunned a day later.

Stooges Bar and Grill bartender Kyla Kenady said lights suddenly flickered as she took a beer to a customer on the patio.

“I saw a plane in the sky coming down over top of our volleyball courts in flames,” she said. “In that moment, I panicked. I turned around, ran through the bar screaming, telling everyone that a plane was crashing.”

The governor predicted that that death toll would rise, saying authorities were looking for a “handful of other people” but “we do not expect to find anyone else alive.”

University of Louisville Hospital said two people were in critical condition in the burn unit. Eighteen people were treated and discharged at that hospital or other health care centers.

The airport is 7 miles (11 kilometers) from downtown Louisville, close to the Indiana state line, residential areas, a water park and museums. The airport resumed operations on Wednesday, with at least one runway open.

The status of the three UPS crew members aboard the McDonnell Douglas MD-11, made in 1991, was still unknown, according to Beshear. It was not clear if they were being counted among the dead.

UPS said it was “terribly saddened.”

The Louisville package handling facility is the company’s largest. The hub employs more than 20,000 people in the region, handles 300 flights daily and sorts more than 400,000 packages an hour.

Jeff Guzzetti, a former federal crash investigator, said a number of things could have caused the fire as the UPS plane was rolling down the runway.

“It could have been the engine partially coming off and ripping out fuel lines. Or it could have been a fuel leak igniting and then burning the engine off,” Guzzetti said.

The crash bears a lot of similarities to one in 1979 when the left engine fell off an American Airlines jet as it was departing Chicago’s O’Hare International Airport, killing 273 people, he said.

Guzzetti said that jet and the UPS plane were equipped with the same General Electric engines and both planes underwent heavy maintenance in the month before they crashed. The NTSB blamed the Chicago crash on improper maintenance. The 1979 crash involved a DC-10, but the MD-11 UPS plane is based on the DC-10.

Flight records show the UPS plane was on the ground in San Antonio from Sept. 3 to Oct. 18, but it was unclear what maintenance was performed and if it had any impact on the crash.