HOLYOKE, Mass. (AP) _ Police arrested a man as he ran with his pants on fire from a burning apartment building and charged him with setting the blaze, police said Tuesday.

Patrolman David Fournier was on patrol Monday night when he saw James J. Wawrzyniak, 25, of Winsted, Conn., run out with his trouser leg on fire, Deputy Chief John Barnett of the arson squad said.

''The gasoline fumes must have gotten inside his pants,'' said another arson investigator, William Porter.

Wawrzyniak and the tenants of the five-story building were not injured, Barnett said.

Residents had extinguished the fire by the time firefighters arrived.

Wawrzyniak was held at the police station pending arraignment.