Cases of vaping-related illness in Utah rose to 114, up from 109 two weeks ago, the state health department reported on Tuesday.

Thirteen more potential cases were being investigated, health officials said. The vast majority of cases appear to be connected to THC cartridges, according to the Utah Department of Health (UDOH) report.

“Given the evidence, vaping THC cartridges or ‘carts’ is likely the driver of this outbreak of severe lung injury,” health officials wrote. “The UDOH recommends people do not vape THC cartridges until we learn more.”

Nearly 90 percent of Utah’s patients vaped THC alone or in combination with nicotine, according to the updated statistics. Of those, nearly all obtained their carts from a friend, a small dealer or online. Fewer than 10 obtained their THC carts from out-of-state dispensaries and in-state vape shops. THC is illegal in Utah.

The CDC last week confirmed that vitamin E acetate, a popular cutting agent frequently found in street-bought THC carts, was believed to be a factor in the illness. Of 19 THC carts that patients provided to the state for testing, 89% were found to contain vitamin E acetate, Utah health officials said.

“In contrast, no nicotine products tested showed any unexpected compounds,” health officials wrote.

More than 2,000 patients nationwide have developed the mysterious illness, which often starts with flu-like symptoms and progresses into severe respiratory distress and gastrointestinal problems. In Utah, about three-quarters of patients have required hospitalization, health officials reported.

Intermountain Healthcare last week released guidelines it has developed for treating patients with vaping-related illness. Steroids have been effective in all cases treated at Intermountain, doctors found, but some of the patients with severe symptoms showed residual effects.

The illness has caused one death in Utah; that person did not receive any medical care, health officials have said.