An explosion at a Falls Church townhouse was accidentally set off when an electrical spark ignited about a dozen aerosol insect repellant containers, according to the Fairfax County fire department.

A man was injured and 11 people were displaced from two adjoining townhouses in the 2800 block of Pine Spring Road. It happened at about 7:15 p.m. Sunday night.

According to fire investigators, an electrical spark from a nearby refrigerator ignited the cans. The explosion severed several floor joists and pushed out one of the room walls. It also damaged an adjoining townhouse, fire officials said.

The man who was hurt suffered non-life threatening injuries and was transported to INOVA Fairfax Hospital for treatment.

Red Cross is assisting the people displaced from their homes. Fire officials did not provide an estimate of the damages.