A man driving a stolen mini­van died Saturday after he apparently suffered a medical emergency and crashed head-on into an MBTA bus that had stopped for passengers in Dorchester, police and transit officials said.

Four bus passengers and the bus driver suffered non-life-threatening injuries and were taken to area hospitals, said a Boston police spokeswoman, Officer Rachel McGuire.

Police are investigating the cause of the crash, she said. The van had been reported stolen in Quincy on Friday, she said.

Officials did not identify the minivan driver, but Transit Police Superintendent Richard Sullivan said he was in his 20s.

The crash occurred at about 9:50 a.m. Saturday at the intersection of Talbot Avenue and Lithgow Street, McGuire said.

There is a traffic camera at that intersection, she said, and police will check to see if the crash was videotaped.

On Saturday afternoon, the Ashmont Route 22 bus remained on Talbot Avenue, cut toward the curb and into the right turn lane.

The van, a dark-gray Dodge Caravan, had apparently left its own lane and struck the driver’s side front of the bus. Airbags appeared to have deployed in the van.

At least a half dozen Boston police and Transit Police cruisers were at the scene, blocking off the intersection to traffic. Investigators could be seen taking photographs of the vehicles.

Maria, a resident of the Latin Academy Apartments who asked that her last name not be used, said, “I jumped up as soon as I heard the crash.’’

She said she saw about 10 people run up to the crashed vehicles, and could hear one woman yelling at the occupants to not move.

About five minutes after the crash, the first of three ambulances arrived.

The minivan driver was taken away by stretcher, Maria said, to the first ambulance that arrived.

“I kept thinking, how did he end up on the other side of the road?’’ said Maria.

A woman wearing a neckbrace walked from the bus to another ambulance, which also left the scene, said Maria.

A wrecker took the minivan away shortly before 1 p.m. The front of the van was crushed inward, while the bus sustained damage to the driver’s side front corner.

Leah Snow, who lives on Lithgow Street, said she saw the bus driver, who appeared to be distraught, seated near the scene after the crash.

She said traffic crashes frequently occur at that intersection.

Saturday morning’s crash was the second one she has seen involving a car traveling on Talbot Avenue toward Lithgow Street striking a vehicle in the oncoming lane.

“Don’t ask me how they get on that side of the road,’’ she said.

Globe correspondent Mina Corpuz contributed to this report. John Hilliard can be reached at john.hilliard@ globe.com. Evan Allen can be reached at evan.allen@globe. com. Follow her on Twitter @evanmallen.