Nevada ? A hepatitis C outbreak was caused by workers improperly reusing syringes and medicine vials at a Las Vegas clinic, federal health officials said Friday.

The Centers for Disease Control and Prevention was contacted by state health officials earlier this year after two people treated at the now-closed Endoscopy Center of Southern Nevada were diagnosed with hepatitis C.

Officials have linked 84 cases of the liver disease to the clinic after notifying 50,000 patients of the clinic to be tested.

CDC investigators said in a report to the Nevada State Health Division that during visits to the clinic, they saw employees reusing syringes to give a sedative and that interviews suggested it was common practice.

“This was considered the most likely mode of transmission,” the report said.