Four people sustained injuries after a Dippen Dots building exploded in McCracken County on Friday night. All four victims were transported to local hospitals to receive additional treatment. There is no update on their condition at this time. ATF officials were at the site of the explosion on Monday to determine what caused the explosion. The facility will be closed until the investigation is finished. The business did have a nitrogen leak. It is yet to be determined whether the leak caused the explosion. Officials say the explosion happened around 9 p.m. local, state and federal units are working on an investigation.