Seven hurt in explosion at county fair

Saturday's explosion left seven people injured.

RIDGEVIEW, Washington (CNN) -- An explosion on a ride at a county fair Saturday left seven people injured.

The explosion on "The Star Dancer" occurred around 5 p.m. PDT (8 p.m. EDT).

"The explosion came after a mechanical failure during routine maintenance on the ride," said Clark County Fire Department spokeswoman Leah Carr. "No riders were on the ride at the time."

The cause of the explosion is still under investigation.

Six of the injured were employees of Butler Amusements, which operates the ride. A 9-year-old boy was also hurt. Three employees and the boy were taken to the hospital for treatment. All but one employee were treated and released. Three injured employees were treated at the scene for minor injuries.

The Star Dancer takes riders on gondolas to the top of a tall tower so they can get a view of the skyline.