LEXINGTON, Ky. (WDRB) -- An explosion rocked a UPS Freight facility in Lexington early Wednesday morning. 

Lexington Fire Battalion Chief Jason Wells said the explosion was caused by acetylene, which is a gas used for welding. Tanks of the gas were on a tractor-trailer parked inside the building in an industrial park on Blue Sky Parkway. 

At least eight employees were in the building, when the explosion happened about 7:44 a.m. on Wednesday. 

WKYT reports that two people were taken to the hospital with injuries described as not life-threatening. Six others were taken to the hospital for observation in what Wells called a mobile ambulance bus. He said the injuries ranged from minor burns to concussion-type injuries. All of the employees were awake and alert. 

Wells said there is nothing suspicious about the explosion, and it is being investigated as an accident. 

The building used for UPS vehicle maintenance sustained "significant damage," according to Wells.  The roof, interior walls and the rear of the building were being checked for structural stability. 

Investigators expect to be on the scene for several hours to make sure the area is safe and to determine what happened. 

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