SPRINGFIELD — A hazmat incident closed four blocks of Main Street and forced residents to shelter in place for several hours Monday night as police and firefighters responded to a suspected suicide with hazardous gas released inside a vehicle.

Responders found one victim dead in a vehicle, Eugene Springfield Fire Battalion Chief Mike Caven said.

"It sounds like we had somebody commit suicide with a hazardous gas in the vehicle," Caven said Monday night. "They're locking down the area, (asking people) shelter in place until they can make sure everything's ventilated."

The gas released was hydrogen sulfide, and the chemicals were isolated to the one vehicle, said Battalion Chief Anthony Bucher, who responded initially.  

"They've just been mitigating the hazard … that's why the area is cordoned off," Bucher said Monday night. 

The vehicle, a black SUV, was parked near the intersection of Main Street and Pioneer Parkway East, and the first report came in at 4:35 p.m. according to the dispatch call log. Upon arrival, the victim was removed from the vehicle and emergency responders tried to resuscitate them but were unsuccessful, Caven said. 

Also known as H2S, sewer gas, swamp gas, stink damp and sour damp, hydrogen sulfide is a colorless gas known for its pungent "rotten egg" odor at low concentrations. It is extremely flammable and highly toxic, according to U.S. Occupational Safety and Health Administration.

Fire officials also investigated the victim's apartment, but found no other hazardous materials, Caven said.

He did not have additional details to provide Tuesday. 

Dean Potter, a 41-year-old Springfield resident, said he noticed a strong gas smell when he got off the bus at Springfield Station earlier Monday.

"It was like a rotten eggs, natural gas smell," he said.

A public safety alert was delivered via cellphones at 5:21 p.m. Monday, calling it a hazmat incident. The fire department asked residents who live or work in the vicinity to shelter in place while crews responded. The shelter in place order was lifted at 7:25 p.m. Main Street was closed from Pioneer Parkway East through to Sixth Street, and ESF asked residents to avoid the area. 

Police, fire and and public works vehicles were stationed around downtown to direct traffic and keep people out of the area, which was roped off with caution tape. 

Main Street was reopened around 8 p.m. Monday.

Springfield police officers assisted the initial fire crew and were exposed to the chemicals, but were later cleared and had no symptoms, Caven said.

Louis Krauss covers breaking news for The Register-Guard. Contact him at lkrauss@registerguard.com, and follow him on Twitter @LouisKraussNews.