As many as 15 teenagers or young adults have now been hospitalized in Minnesota for severe lung injuries associated with vaping or e-cigarette use, the state Health Department said in an update Thursday.

The department reported 11 new presumptive cases, on top of the four confirmed cases that were detected at Children’s hospitals in the Twin Cities in recent weeks.

While state investigators are still verifying that the injuries are associated with vaping, the new cases are part of what is now a national outbreak. The U.S. Centers for Disease Control and Prevention has reported 153 possible cases in 16 states that occurred since June 28.

Most of the cases in Minnesota involved people younger than 18, said Health Department spokesman Doug Schultz. Investigators aim to determine if certain products or vaping devices are responsible for the new rash of cases. Many of the injured teens were consuming marijuana-based THC products, but traditional nicotine e-cigarettes could be involved.

“We don’t know the exact reasons why they’re occurring at this point,” Schultz said. “We have a number of hypotheses and theories. It does appear this is something new that has come up” rather than a risk that had existed all along but hadn’t been detected until now.

Several teens were so severely injured that they were admitted to intensive care and placed on ventilators. No deaths have been reported in Minnesota, but Illinois on Friday reported its first death related to the vaping illnesses.

Jeremy Olson