Waltham Fire Hazmat Team Helping in Watertown Incident

The medical examiner and a representative of the district attorney's office are on the Arsenal Street scene that has seen a gathering of hazmat teams, police and fire engines from Watertown, Waltham  and Reading, starting shortly after 6 tonight.

That's when, according to scanner reports, the first police and fire responded to a Tier 3 hazmat situation.

Patch correspondent Stephen Walsh, who is on scene at Arsenal Street, reports there is a silver car on-scene with a note taped to the passenger-side window saying "poison used, stay away."

Walsh also reports there is a body inside the vehicle.

 Members of the Department of Fire Services (District Two) hazmat team arrived on the scene earlier this evening, along with the State Police bomb squad and a Reading Fire Department hazmat truck. 

Crews had set up a tarp around the scene as well as a decontamination zone. 

The car is parked in a lot across from the AutoZone store on Arsenal Street.

The staging for the incident is set at , 450 Arsenal St. and scanner reports say multiple buildings were evacuated. 

Reports from the Twitter feed of firstduephotos (Ted Pendergast) said the incident involved hydrogen sulfide.

We are awaiting a news conference.

Stephen Walsh contributed to this report.