Officials believe gas caused Dorchester home explosion ← Related Article Visit The Boston Globe Share on Twitter Share on Facebook Comment on this Scroll to top of page Pat Greenhouse/Globe Staff Investigators believe gas triggered an explosion at a Dorchester home Wednesday night. Pat Greenhouse/Globe Staff Two elderly people are in critical condition and 10 others were injured, an official said. Bill Brett for The Globe The blast at 27 Hansborough St. happened around 9:20 p.m. Boston Fire Department The explosion quickly grew into a three-alarm fire. Bill Brett for The Globe When firefighters arrived, flames were shooting out the windows of the two and a half story building, an official said. Boston Fire Department A fire official said damage has been set at $500,000. Boston Fire Department The city’s Inspectional Service Department will assess the building’s stability .