The University of Pittsburgh Medical Center (UPMC) reported that Kwiatkowski was a contract employee who worked at the facility for 47 days in 2008, until he was fired for being in an area of the hospital where he was not assigned. Kwiatkowski was assigned to the interventional radiology department but was found in a neighboring operating room that did not perform angiography, according to a UPMC statement.

UPMC said it notified his employer, Maxim Staffing Solutions, of his termination. The hospital is working with state and county health authorities to identify patients who may have come into contact with Kwiatkowski to see if they were at risk of contracting hepatitis C.

Two years later, Kwiatkowski was fired from another hospital, Arizona Heart Hospital, after he was allegedly found unconscious in a hospital bathroom with a syringe and needle nearby, according to published reports. That facility and another hospital, Maryvale Hospital, have announced hepatitis C testing programs for patients seen at their cardiac catheterization labs during Kwiatkowski's terms of employment.

Health authorities in at least a half-dozen states where Kwiatkowski worked are investigating whether patients may have been infected through his alleged diversion of fentanyl for his own use. The case came to light when Kwiatkowski was arrested on July 19 and charged with infecting patients at Exeter Hospital in New Hampshire.