Federal health authorities are under fire for their uncertain public warnings after one death and nearly 200 instances of vapor-related lung diseases, some of which are associated with the far more risky practice of vaporizing marijuana oil than nicotine.

Some state health departments and media accounts indicate that many instances of these serious lung issues involve tetrahydrocannabinol, recognized as THC, a chemical in marijuana that can have psychological impacts.

Boston University Public Health Professor Michael Siegel said the Centers for Disease Control and Prevention is “unnecessarily vague” about defining the accidents as simply vaping-related when a lot of individuals might have been harmed by vaping THC oil.

“Based on what we know now, I think there’s enough to tell people: Don’t vape THC oils – especially products that are bought off the street,” Siegel said. “There are certain things the agency could be recommending right now that could potentially save lives and prevent this from happening by being much more specific.”

The CDC, the Food and Drug Administration and state health organizations claim that they are finishing the painstaking job of identifying prevalent variables that may have caused the spread of vaping-related lung diseases, primarily affecting young adults.

Siegel recognized that he was not deprived of all the data the CDC had collected. The Agency probably does not understand whether THC is the only guilty party, he said, but the public would probably profit if the Agency advised vapers to stay away from THC oil.

“There are millions of people vaping out there,” said Siegel, who supports vaping as a way for adults to quit smoking. “When they get this advice ‘Well, we don’t know what it is; it’s vaping,’ that doesn’t help anyone. So I think they need to try to be specific.”