Three former surgery patients are suing a Colorado hospital after they claimed nearly 3,000 had been exposed to a blood-borne disease that a medical technician with a drug addiction carried.

The plaintiffs in the lawsuit are claiming the Swedish Medical Center in suburban Denver was negligent in its hiring practices and supervision of a surgical technologists who had allegedly been caught switching a syringe that had an opitate called fentanyl citrate with some other substance during a surgery a couple months back, according to a Reuters report.

Rocky Allen, 28, was indicted by a federal grand jury on two felonies last month: one count of tampering with a consumer product, as well as one count of obtaining a controlled substance by decit. The complaint states that Allen carries a blood-borne pathogen.

Upon discovering the situation, the hospital notified 2,900 patients who underwent surgery between August 2015 to January 2016 while Allen was employed there.

The three patients who are suing are asking for compensation for emotional distress. They had undergone surgery over that time period. Each of them tested negative for any blood-borne disease, but they will need additional screens for another six months.

The lawsuit claims that Allen had been fired numerous times before over drug-related offenses, and had also been court-martialed by the Navy for stealing fentanyl while deployed in Afghanistan, and the hospital should not have had him working in surgery, according to the report.

Swedish said it had fired Allen immediately after the revelations and reported it to authorities and notified patients, arguing that other facilities he had worked at did not do this.

Allen is out on a $25,000 bond and was ordered to a halfway house while the trial is going on.