Officials in South Carolina say two teenage sisters are facing charges after pepper spray was used during a fight on a school bus.

The Richland County Sheriff's Department tells local news outlets that the 16-year-old and 15-year-old siblings were charged with third-degree assault and interfering with the operation of a school bus.

The girls were on the bus going to Westwood High School when an argument started Tuesday.

Officials say the 15-year-old pulled out pepper spray, spraying at another teen, who got off the bus. That's when deputies say the two sisters began fighting a second teenager.

Twenty-one students were taken to hospitals to be checked out. No one was injured.

The 15-year-old also is charged with carrying a weapon on school property.