Regina police said officers on patrol at Evraz Place on Saturday afternoon were informed of a possible bear spray incident on the east end of the midway.
Several people reported something had been sprayed in the air.
Police said the victims had varying degrees of symptoms consistent with bear spray, including red eyes, runny noses and general irritation of their eyes, nose and throats.
Several victims were taken to a first-aid centre for treatment and police believe other victims left the event.
Officers took two youth into custody and police said they seized a canister of bear spray and a “very realistic” Glock-styled BB gun.
A 15-year-old boy is facing charges of possession of a BB gun for a purpose dangerous to the public peace, breach of an undertaking and mischief.
A 13-year-old boy is facing charges of unauthorized possession of bear spray, possession of a prohibited weapon, carrying a concealed weapon and mischief.
They cannot be identified under provisions of the Youth Criminal Justice Act.
Both made their first appearance in youth court on Monday morning.
Investigators are encouraging anyone who was a victim in this incident to file a police report.