SALISBURY, Md. - An 11-year-old boy was injured Tuesday night while rescuing his 2-year-old sister from their burning apartment in Salisbury. 

The Maryland State Fire Marshal's Office said it happened at around 6 p.m. in apartment 601 of a two story, eight-unit apartment building located at 1302 Jersey Road. A smoke alarm was present and operated, notifying occupants of the fire in time to escape. 

The Salisbury Fire Department responded to the scene and got the blaze under control within 10 minutes. 

An 11-year-old boy who lives in apartment 601 exited the apartment upon discovering the fire. However, investigators said that once the boy was outside, he realized his 2-year-old sister was still inside. The boy ran back into the apartment and was able to rescue the toddler from the second floor. The boy was slightly burned in the arm while making his second escape from the apartment with his sister.  His injuries were minor enough that they did not require on-scene medical attention, deputy state fire marshals said. 

The fire caused an estimated $250,000 in damage to the structure, and another $40,000 in damage to its contents. 

Of the eight apartment units, two units are uninhabitable as a result of the fire. Their occupants are being assisted by the American Red Cross. 

Deputy state fire marshals ruled the fire accidental and said it was caused by an unspecified electrical event at an outlet in a second floor bedroom.