( CNN ) -- A man lost both of his hands and four other people were injured in an explosion Friday morning at a southern Boston apartment building , Boston police said . Police spokeswoman Neva Coakley said the nature of the explosion at the building in the Hyde Park neighborhood was n't immediately clear . However , Boston Police Commissioner Edward Davis told The Boston Globe that the man who lost his hands had been mixing chemicals in his basement apartment , and that the chemicals exploded . Two people , including the man who lost his hands , were taken to a hospital , and three others were treated at the site in the Hyde Park neighborhood for unspecified injuries , Boston police said . Davis said the man mixing the chemicals might have been experimenting with fireworks , and investigators did n't immediately know why the chemicals exploded , according to the Globe . The incident had `` no connection to terrorism , '' Davis told CNN affiliate WCVB . `` He told us he was experimenting , '' Davis said , according to the station . Firefighters were called to the four-story apartment building at 15 Riley Road shortly after 9 a.m . They quickly put out a fire in the basement , fire department spokesman Steve MacDonald said . A caller reported hearing bangs and seeing smoke coming from the building , WCVB reported , citing police . MacDonald said Friday morning that investigators were checking out potentially hazardous chemicals at the scene . But the site , which had been cordoned off during the initial probe , was deemed safe by Friday afternoon , Coakley said .
NEW : Scene is now safe , Boston police say . Four other people are treated for injuries , police say . A man said he was experimenting with chemicals , an official tells a newspaper . The incident happened at the home of one of the suspects in the bombings.