Attorneys representing both living and deceased patients of an Oregon hospital filed a $303 million lawsuit against the facility on Tuesday after a nurse was accused of replacing prescribed fentanyl with nonsterile tap water in intravenous drips.

The wrongful death and medical malpractice complaint accuses Asante Rogue Regional Medical Center in Medford of negligence. The suit says the hospital failed to monitor medication administration procedures and prevent drug diversion by their employees, among other claims.

Dani Marie Schofield, a former nurse at the hospital, was arrested in June and charged with 44 counts of second-degree assault. The charges stemmed from a police investigation into the theft and misuse of controlled substances that resulted in patient infections. She has pleaded not guilty.

The 18 plaintiffs in the new suit include nine patients and the estates of nine patients who died. According to the suit, the hospital began informing them in December that an employee had replaced fentanyl with tap water, causing bacterial infections.