WESTMINSTER, Colo. -- An explosion at a Westminster apartment complex sent scores of residents into the cold Tuesday night.

The incident was reported at about 8 p.m. at the Terrace Gardens in the 7100 block of Hooker Street and displaced approximately 100 residents.

Damage from the explosion was confined to the boiler room, according to firefighters. There was no smoke or fire damage in the apartments. An investigation into the cause on Wednesday determined that it was the result of a gas line, 7News reported.

Two maintenance workers were trying to repair the boiler at the time of the explosion. Both received minor burns and were hospitalized.

Residents had complained about a lack of heat and the broken boiler on Tuesday.

Many of the residents who were displaced stayed with family or friends, and the others were placed in a local hotel, through the assistance of the American Red Cross and COCAT, a restoration and construction company.

All electrical power was shut off to the building and it was not known when the families will be able to return, fire officials said. Structural engineers will examine the building Wednesday.