Updated

Authorities in at least six states are investigating whether a traveling hospital technician accused of infecting 30 people with hepatitis C in New Hampshire also exposed earlier patients to the liver-destroying disease.

David Kwiatkowski, a former technician at Exeter Hospital, was arrested Thursday morning at a Massachusetts hospital where he was receiving treatment. Once he is well enough to be released, he will be transferred to New Hampshire to face federal drug charges, said U.S. Attorney John Kacavas, who called Kwiatkowski, 33, a "serial infector" who worked in at least half a dozen states.

Authorities believe Kwiatkowski stole drugs from a hospital operating room in another state, but they declined to name any of the other states, saying only that they are not clustered in one part of the country. They would not say in what hospital Kwiatkowski was being treated at so he couldn't be contacted for comment.

"We are closer to the beginning of our investigation than the end," Kacavas said.

Investigators believe Kwiatkowski, 33, stole syringes containing fentanyl, a powerful anesthetic more potent than morphine, and injected himself with them. They said he then put another liquid, such as saline, into the syringes, which were later used for patients. They said a search of his vehicle found an empty fentanyl syringe and several needles.

Originally from Michigan, Kwiatkowski worked at Exeter's cardiac catheterization lab from April 2011 through this past May, when he was fired. He told investigators that he learned he had hepatitis C in May, but Kacavas said there is evidence Kwiatkowski had the liver-destroying disease since at least at least June 2010.

"This serial infector has been contained, and the menace he posed to public health and safety has been removed," Kacavas said.

Though state and local health departments aren't required to report such outbreaks to the Centers for Disease Control and Prevention, in a report released in June, the agency said it was notified of 13 outbreaks nationwide between 2008 and 2011. Of those, seven occurred in outpatient facilities; most were traced to unsafe injection practices.

At least two have resulted in criminal charges, however, including a Colorado woman who was convicted of stealing syringes filled with painkillers from two hospitals where she worked and replacing them with used syringes. The syringes were later used on surgical patients, and up to three dozen patients were found to have hepatitis C after being exposed.

Kacavas said New Hampshire is working with the federal Centers for Disease Control and Prevention, law enforcement and departments of public health in other states where Kwiatkowski worked.

"I'm unaware of such a scheme with such reach," he said. "This one has the potential for very far reaching implications."

According to an affidavit, Kwiatkowski was observed at times leaving the lab sweating profusely and attending procedures on his off days. One witness said he appeared to be "on something." At least once, he was sent home for the day after a colleague told a supervisor that he was unfit to perform medical care, Kacavas said.

Kwiatkowski was what is known as a "traveler," a technician hired by hospitals for temporary stints around the country. In a statement, Exeter Hospital said he underwent drug testing and a criminal background check when he was hired.

"It is deeply disturbing that the alleged callous acts of one individual can have such an impact on so many innocent lives. As a result of his alleged actions, people in our community, who in many cases are the friends and neighbors of the 2,300 people who work here, now face the challenge of a potentially chronic disease," said Kevin Callahan, president and CEO of Exeter Hospital.

The hospital declined to comment further about Kwiatkowski, citing the ongoing investigation.

Hepatitis C is a blood-borne viral infection that can cause liver disease and chronic health issues. Altogether, 31 people, including Kwiatkowski, have tested positive for the same strain of the disease since the investigation began in late May.