Mayfield (United States) (AFP) - It was a banal industrial building, low, wide and largely unexceptional, with a few windows and a sign proudly declaring its occupant: "MCP, Mayfield Consumer Products." 

It is no more.

Inside what was once a candle factory, dozens of workers were trapped when the most powerful tornado in the history of Kentucky -- and possibly of the entire United States -- rumbled through like a freight train Friday night.

In all, 110 employees were inside, working to supply scented candles and essential oils -- popular products during the holiday season. The factory had been operating around the clock.

But that night the exceptionally powerful storm flattened the factory -- as it did much of the nearby town of Mayfield.

By Sunday morning, workers were using bulldozers and construction equipment to clear debris from the historic town's devastated center, working in chilly temperatures but under a bright sun.

Forty employees of the candle factory were rescued in the early hours of Saturday, Governor Andy Beshear said. He did not say how many might have made their own way out on their own.

Now, the hopes of finding survivors are fading fast.

"I pray for it," Beshear told CNN on Sunday. "It would be an incredible miracle." But, he acknowledged, no survivor had been found since a few hours after the storm ripped through.

'Terrifying experience'

The governor said at least 80 deaths have been confirmed in Kentucky, the state hardest hit by a slew of tornadoes.

Many of the dead perished at the Mayfield candle factory, which lay squarely in one twister's path.

MCP was a major employer in the town of 10,000. A family-owned business created in 1998, it had recently been hiring -- a rarity in an America where small manufacturers more often lose out to international competitors.

"Our Mayfield, Kentucky facility was destroyed December 10, 2021, by a tornado, and tragically employees were killed and injured," CEO Troy Propes said in a message on the company website.

"Our employees, some who have worked with us for many years, are cherished."

The factory also employed trusted inmates from a local prison.

Since late Friday, rescue workers have been desperately searching through the tangle of debris that is all that remains of the factory, where fallen girders and twisted sheet metal are piled high.

They have been seen removing corpses, while advancing gingerly through the wreckage with heavy equipment. Specially trained dogs sniff the debris to find anyone -- dead or alive -- still buried.

Jason Riccinto had worked at the factory, but as a volunteer fireman he has spent hours with a search crew on the scene.

"We moved stuff by hand to search for people. Once we knew nobody was there, they get the excavators," he told AFP. "It's search, pull back, search, pull back."

"It's total devastation."

The His House Ministries, a nondenominational church near Mayfield, has been providing food and clothing for survivors -- and a space for the county coroner to do his work, pastor Stephen Boyken said.

People "come with pictures, birthmarks -- they talk now about using DNA samples to identify those who have been lost," he said.

Those who made it out alive described scenes of terror and anguish.

One trapped factory worker, Kyanna Parsons-Perez, broadcast herself on Facebook Live, pleading in a quavering voice for anyone to come help.

The harrowing sound of fellow workers crying and moaning could be heard. But there was also the sound of one woman's voice quietly seeking to calm the others.

Parsons-Perez miraculously survived. 

"It was absolutely the most terrifying thing I have ever experienced in my life," she said later.