HazMat crew on Semont Rd.: Boston Firefighters spent the morning investigating an "irritant" found in the air inside 14 Semont Rd. Photo by Ed Forry

(Updated— Friday, July 8, 1:30 p.m.) — Hazardous material teams from the Boston fire and police departments spent the morning at a house on Semont Rd. in Dorchester's St. Mark's Area as they investigate an airborne "irritant" that was alleged to have been used in an attack on a man this morning. Instead, the man who claimed to be the victim has been led away in handcuffs.

Boston Fire Department spokesman Firefighter Steve MacDonald says that investigators now believe that a "mace-like product" was sprayed inside the house at 14 Semont Rd. at some point overnight.
Boston Police confirm that a man who claimed to be the victim in the bizarre sequence was himself arrested on an outstanding warrant.

The investigation began this morning after the not-yet-identified man entered the emergency room at Boston Medical Center around 8 a.m. and said he'd been sprayed in the face with a canister at Wainwright Park. Boston Fire and police responded to the park, but did not find anything there, MacDonald says. The investigation then turned to the man's apartment on the first-floor of a house at 14 Semont, where more than a dozen police and fire vehicles have been parked on the sidestreet and Dorchester Ave since around 8:45 a.m.

The man was released from Boston Medical Center and returned to Semont Rd. A chemist and HazMat unit was called to the scene at Semont Rd. after the first fire crews arrived at the apartment and could feel an irritant on their faces. They immediately evacuated the house and cordoned off much of the street.

MacDonald said that fire officials were "waiting for test results to come back from state lab" before he could say for sure that the irritant in the unit was mace.

Emergency vehicles were preparing to leave the scene around 11:30 a.m., he said.