CHICAGO (CBS)–A gym in west suburban Wheaton is being sued by the family of a 7-year-old who was killed due to a head injury in the facility.

A spotter was assigned to look after the child, Brady Doherty, while he was at My Gym Children’s Fitness Center on Sept. 30 for a kids’ birthday party.

Doherty was using a zipline attraction when he was vaulted into an unpadded pole, then plummeted to the floor, striking his head on an unpadded cement floor, according to the lawsuit, filed by the family’s attorneys, Corboy and Demetrio.

Doherty, who was not wearing a harness or a helmet, died on October 2, the lawsuit says.

Lawyers for the family allege that My Gym failed to properly install and provide safety devices that would have prevented Brady’s injuries and death.

“The Doherty family is worried about similar unsafe zipline attractions throughout the country and hope this case prompts My Gym to remove its zipline from all locations,” said attorney Michael K. Demetrio, in a statement.