A tow motor exploded and caught fire while it was being pulled off a semi-truck for repair overnight, injuring two people in southeast Davidson County. The two workers were transported to a medical facility in critical condition according to Charles Shannon of the Nashville Fire Department. The tow motor may have had a propane leak and a spark may have ignited the explosion as it was being pulled off the trailer-trailer, Shannon said. The explosion was at around 3:30 a.m.