WTOP is reporting a large explosion at a shopping center in Prince George’s County. Six people, most of them firefighters, were seriously injured in the blast. The firefighters had been there in response to a call for a natural gas leak at the Penn Mar shopping center in Forestville, Md. See also the AP, and WTOP provides the aerial photo. Looks like the mall was basically leveled at one end. Luckily, the building was evacuated shortly before the explosion.