Two hospitals in Washington state warned nearly 1,500 patients they may have been exposed to HIV, hepatitis B virus (HBV) and hepatitis C virus (HCV). It’s the latest development in an ongoing drug diversion scandal, in which a traveling surgery technician has been charged with stealing and swapping syringes of painkiller drugs in at least four states, Access WDUN reports.

The alert comes just weeks after state health officials in Colorado and Arizona warned more than 3,000 surgery patients to get tested for blood-borne illnesses, after health authorities at Glendale hospital in Phoenix uncovered evidence that surgery tech Robert “Rocky” Allen, had been taking fentanyl syringes from the surgery room and then using the powerful opioid narcotic. It was later discovered that Allen had been fired from at least four medical centers in four different states under similar allegations, setting a chain reaction of HIV and hepatitis warnings across the Southwest.

Northwest Hospital and Medical Center in Seattle is now offering free hepatitis and HIV testing to 1,340 patients who received surgery at the facility in late 2012, during a 10-week window Allen worked at the facility before being fired for undisclosed reasons. Nearby Lakewood Surgery Center, where Allen also worked for a short time, said it had alerted 135 patients. Despite the warnings, both hospitals, as well as the U.S. Centers for Disease Control and Prevention are currently characterizing the risk of infection as low.

Allen, 28, who was arrested last month in Colorado, has plead “not guilty” against federal court charges of tampering with a consumer product and obtaining a controlled substance by deceit. The surgery tech’s defense has said that Allen is a Navy veteran who suffers from post-traumatic stress disorder and started using opioid painkillers after witnessing war horrors in Afghanistan. Allen is currently out on a $25,000 bail and has been ordered to stay at a halfway house and get drug treatment as court proceedings continue.

Other hospitals implicated in the exposure alert include: Scripps Green Hospital in San Diego, HonorHealth John C. Lincoln Hospital in Phoenix, and Swedish Medical Center in Denver. So far, no infections linked to Allen have been reported at any of the facilities.