EVANS CITY — A crash involving a BART bus and a train this morning injured 12 people.

About 8:10 a.m. the bus was headed east on Maple Avenue. When it came to a railroad crossing, the driver stopped to look for trains.

When the driver did not see anything, he proceeded to drive and was hit on its driver's side by a train, according to Mike Robb, executive director of the Alliance for Nonprofit Resources, which oversees BART.

He also said there was heavy fog: “It is my understanding that visibility was very limited this morning due to the fog.”

The train, which appeared to be hauling tankers, did not derail and is halted on the track, which is owned by Buffalo and Pittsburgh Railroad. There is no gate or lights at the crossing.

Two passengers were taken by medical helicopters to Pittsburgh hospitals. The driver and remaining passengers were taken by ambulances to hospitals.

According to Allegheny General Hospital spokesman Dan Laurent, three men involved in the crash, ages 35, 38 and 75, arrived at the hospital by ambulance. A woman involved in the crash, age unknown, arrived by medical helicopter. Laurent said the four patients' conditions were being evaluated as of 10 a.m.

The 11 passengers were either developmentally disabled or senior citizens. All on the bus were headed to different locations.

Officials did not release the names of any of the passengers or the driver.

Robb said that it is BART's standard procedure to investigate bus drivers following accidents.

Evans City police were in charge of the accident scene. They had assistance from police from Adams Township, Cranberry Township, Middlesex Township and state police.

Emergency crews from Evans City, Callery, Cranberry, Harmony and Zelienople are on scene. Ambulances from Cranberry, Quality and Harmony also responded.

A police officer said that the bus was knocked on an embankment but was still on its wheels.