While the Cannabis Control Commission requires tests for certain contaminants, it sets no restrictions on ingredients used to flavor or cut the thick marijuana extracts used in vaping products — the very chemicals federal officials now fear are linked to 450 possible cases of lung illness, including five deaths, in 33 states.

US health officials have urged people to stop using the devices for now.

In Massachusetts, the state agency also does not regulate vaping cartridge hardware, even as lab tests and media reports suggest the heating coils in some cheap Chinese-made pods could leach heavy metals into the vapor they create.

Experts warned the lack of oversight around vape additives leaves consumers at risk, and the state flying blind into an emerging public health crisis.

“It’s not enough to say, ‘We know what the active ingredient is, so it’s fine,’ ” said Dr. Sharon Levy, director of Boston Children’s Hospital’s substance use program, adding that popular vape cartridges bear little chemical resemblance to the marijuana plant, which has a long history of human consumption. “Actually, very small differences matter. We’re ignoring all of that. That is a very basic problem.”

So far, none of the patients whose cases are under investigation are from Massachusetts, but state officials said they are investigating “several” possible cases. One patient who died had used a marijuana vape from a licensed store in Oregon.

Cannabis commissioner Jen Flanagan said the agency should discuss whether to regulate additives.

“Everyone should be on alert when they’re vaping anything,” she said.

Vaporizers typically heat concentrated marijuana oil with battery-activated coils. Experts say the resulting vapor can harm the lungs.

The US Centers for Disease Control and Prevention has identified an oily vitamin E-derived compound as a possible common link among some cases, The Washington Post reported. However, federal officials stressed they have yet to make a definitive determination, and continue to analyze samples for a broad range of chemicals, including “cutting agents.”

The state cannabis commission is investigating whether products sold at licensed marijuana stores in Massachusetts include the vitamin E-related compound, a spokeswoman said.