A new report by the US Centers for Disease Control and Prevention (CDC) has linked the vast majority of vaping-related lung illnesses, aka EVALI, to cannabis vapes.

As of January 14th, 82 percent of all cases of EVALI have now been linked to THC-containing vapes, according to the CDC’s new Morbidity & Mortality Weekly Report. Only a third of all EVALI patients used cannabis vapes exclusively, however. Slightly over half (52 percent) of all patients also used nicotine vapes, and 14 percent used nicotine vapes exclusively.

The report notes that incidences of EVALI first began to appear last June, and peaked in September. As of last week, the CDC is reporting that 2,668 people have been hospitalized after vaping, and 60 patients have died from this illness. The number of cases has fallen dramatically since last fall, as news of the illness began to spread. In 2020, there have been relatively few new cases of EVALI.

Many of these cases have been traced back to black market cannabis products, and more specifically to vitamin E acetate, which is sometimes added as a thickening agent to illegal products. The CDC has acknowledged that this illness could be caused by other factors, however. Previous studies have found that cheap vape cartridges can release heavy metal fumes when heated, and other contaminants like mold, pesticides, or fungus, can also cause respiratory issues when vaped.

The CDC also notes that a small percentage of EVALI cases have been linked to legal weed vapes. Perhaps even more worrisome is that the agency does not even divulge where these contaminated legal products were purchased. Several states have recently mandated that legal weed vapes undergo an additional round of safety testing, and some legal products failed these second round of tests. In Massachusetts, some legal vapes were found to have “impermissible levels of lead,” while vaping products in Michigan were recalled over vitamin E contamination.

The report raises more questions than it answers, but many health officials are using it to argue that legislators should back down on efforts to legalize weed. “To approve legalized adult-use cannabis at a time when we know it is making people gravely ill abandons our first obligation of protecting the public,” said New York State Association of County Health Professionals president Daniel Stapleton, CBS 6 News reports.

This shortsighted argument ignores the fact that no other form of cannabis, including edibles or smokable flower, has ever been linked to EVALI. The CDC report also makes it clear that the majority of EVALI cases have been caused by concurrent use of nicotine and THC vapes, while some patients have never even vaped weed. Continuing to prohibit legal, regulated vaping products will also fail to curtail sales of black market products, which health officials still believe are the most likely cause of this illness.

New York state Assemblyperson Patricia Fahy told CBS 6 that the CDC report “points to a need for more regulation.” Governor Cuomo recently promised that the Empire State would finally legalize weed this year, but concerns over the safety of cannabis vaping may impede the progress of cannabis reform. “So how this plays out in the legalization of marijuana really remains to be seen,” Fahy said.