CASA GRANDE, Ariz. - A passenger grabbed the steering wheel of a Greyhound bus while struggling with the driver yesterday and caused the vehicle to roll on its side on a highway, injuring 33 people.

No other vehicles were involved. There were no life-threatening injuries, authorities said.

The passenger, who was smoking a cigarette, became upset after two other bus drivers in the rear of the vehicle told him that he couldn't smoke, said Steve Volden, spokesman for the Arizona Department of Public Safety.

The passenger then went to the front of the bus and banged on the passenger door of the bus, which was traveling at around 70 mph, Volden said.

Unable to open the door, the passenger grabbed the steering wheel and tried to take control of the bus, Volden said.

The bus then went off the roadway. The driver tried to maintain control by bringing the bus back on roadway, but it ended up on its side, Volden said.

The passenger was taken into custody. His identity was not released.

The bus originated from Los Angeles and was headed for Miami, Fla.

The struggle occurred around 1 a.m. during the Phoenix-to-El Paso leg of the trip on Interstate 10, about 50 miles south of Phoenix, said Greyhound spokeswoman Jamille Bradfield.

The injured were taken to area hospitals, where one passenger is in critical condition. The bus driver is in stable condition, Bradfield said.

While the conditions of other passengers were not immediately available, hospitals report that one person on the bus is in good condition, two others are in stable condition and another four were treated and released.

Five people on the bus weren't injured.

he portion of the roadway where the wreck occurred remained closed until 7 a.m. The crash scene had been cleared by late yesterday morning

The Arizona wreck is the third such incident on a Greyhound bus in a month.

On Oct. 3, a Croatian man slashed the neck of a Greyhound bus driver in Tennessee, causing a crash that killed seven passengers. The incident prompted Greyhound to shut down all bus service for a few hours.

Two weeks later, passengers on a Greyhound bus were credited with averting disaster in Utah after they helped thwart an alleged hijacker who tried to overpower the driver and threatened to flip the vehicle. No one was injured.

Bradfield said Greyhound didn't suspend bus service after the Arizona crash because authorities believe it is an isolated incident.