Nearly 300 people at a Massachusetts colonoscopy clinic were recently warned that they may have been exposed to HIV, hepatitis C virus (HBV) and/or hepatitis C virus (HCV), after the state’s health department found equipment at the facility had not been properly cleaned for almost a year, Mass Live reports.

Massachusetts health officials are now urging 293 people who had a colonoscopy at Baystate Noble Hospital in Springfield between June 2012 and April 2013 to get tested. The health warning only applies to people who underwent a procedure with a specific type of endoscope that could not be properly decontaminated in the hospital’s cleaning machines.

The hospital insists that the risk of infection is “low, [but] it is not zero.” So far, no one has been found to have contracted any of the viruses. The hospital has also since changed their cleaning procedures to ensure no other potential exposures occur.

The U.S. Centers for Disease Control and Prevention (CDC) reports that more blood-borne disease outbreaks have been linked to contaminated endoscopes than to any other medical devices.