The Worcester County Fire Marshal's Office responded to a Bishopville fire dispatch for an explosion at 10731 St. Martins Neck Road. Arriving firefighter found a commercial structure, with no fire but evidence of an "over-pressure" explosion. It was quickly discovered the source of the explosion was the building's hot water heater. No injuries were reported with the incident. Fire companies from Bishopville, Showell, Ocean Pines and Ocean City responded to the 1:45PM alarm. The cause of the explosion is contributed to a faulted relief value on the hot water heater.