MANKATO, Minn. (AP) _ A cancer patient who tried to kill himself after watching a television show about Dr. Jack Kevorkian caused a gas explosion that destroyed part of his apartment house, authorities said.

John Campbell, 51, apparently turned on a gas oven to commit suicide, said city Fire Marshal Al Ratzlaff.

Campbell was listed in critical condition Saturday at St. Paul Ramsey Medical Center, which wouldn't provide details of his injuries.

Investigators weren't sure what ignited the gas Friday, Ratzlaff said.

The fire destroyed third-floor apartments, and other parts of the building were damaged by smoke and water, Ratzlaff said. Damage was estimated at $100,000 and seven people were temporarily displaced.

The owner of the building, Avis Woehrle, said Campbell came downstairs after the explosion and told her: ''I'm on fire. I tried to kill myself. Call the fire department.''

She said Campbell told her he didn't mean to involve anyone else.

Kevorkian, a retired pathologist, faces trial April 19 on a charge of violating Michigan's assisted suicide law. Kevorkian has been present at 20 deaths since July 1990.