The Boston Fire Department reports investigators are still trying to figure out what sparked a two-alarm fire that damaged three addresses on Dean Street in Dorchester, displacing nine residents and sending two firefighters to the hospital.

The fire, reported around 5:40 p.m. at 23 Dean St., did an estimated $300,000 in damage to 21-23 Dean and $50,000 in damage to 27 Dean St., the department says.