The federal government will allow the sale of cannabis vaping products starting next week despite not having tested the health effects of inhaling substances emitted from such devices. At least one cannabis company has preemptively pulled its product over health and safety concerns, CBC News has learned.

Cannabis vapes are among a series of new products — including edibles, extracts and topicals such as lotions — that can be legally sold in Canada as of Tuesday. 

Newfoundland and Labrador and Quebec have outright banned the sale of cannabis vapes while Nova Scotia will not allow flavoured versions. 

Health Canada says that while it has tested the ingredients in cannabis vaping liquids, tests on the vapour emitted when those compounds are heated have not yet been done. 

"No legal products are on the market as of today," Eric Morrissette, a spokesperson for the health agency said in an emailed statement Thursday. "So, there has been no analysis done."

Products released in midst of vaping illness outbreak

The release of the products comes amid an outbreak of vaping-associated lung illnesses across North America involving cannabis vapes and nicotine e-cigarettes. 

As of Dec. 10, 2,409 cases, including 52 deaths, have been reported to the U.S. Centers for Disease Control (CDC) in all 50 states this year. 

"In the middle of an epidemic in the United States, they still somehow come to the conclusion that there's nothing to worry about here and we can go ahead and sell cannabis vaping products," said Dr. Matthew Stanbrook, a respirologist at Toronto Western Hospital and deputy editor of the Canadian Medical Association Journal. 

"It just really speaks to a complete lack of attention to providing any safeguards here."

There have been 14 cases of vaping-associated lung illness reported to the Public Health Agency of Canada as of Tuesday. Three occurred in British Columbia, two in New Brunswick, four in Ontario, and five in Quebec.

"It's sort of like the worst time that you could release these products in Canada," said Dr. Mangala Narasimhan, the regional director of critical care medicine at Northwell Health in New York City, who has treated close to 40 cases of the illness. 

"It's crazy to me that they're allowing this to continue and that they're actually going to introduce it in Canada, knowing everything that we know."

The majority of the cases of vaping illness are linked to illicit cannabis vapes. The CDC has not singled out any one brand but recommends that people not use the devices at all.

"If the leading authority in the world is making that statement, then who am I or others to challenge them?" said David Hammond, a professor of public health at the University of Waterloo who researches vaping.

"And I would suggest that the actions in Quebec, Newfoundland and Nova Scotia are more in line with that. They are still trying to figure out what is killing people and putting people in hospital."

Health Canada said in a statement that there is a vast illegal market for cannabis vaping products in Canada and that providing legal access to regulated cannabis products "is one of the best ways to protect Canadians from the risks posed by products from the illegal market."

The health agency said it is in close contact with the CDC and the U.S. Food and Drug Administration "to better understand their investigations into the cause or causes of the illnesses."

Cannabis company holding back on releasing vapes 

HEXO, a Canadian cannabis company that made headlines after it announced in October it would sell cannabis for $4.49 a gram, says it will not release cannabis vapes next week as planned because of concerns over the safety of the products. 

"We understand that diluting agents found in some cannabis extracts are under increased scrutiny for having potential negative health impacts," Isabelle Robillard, HEXO's vice-president of communications, said in a statement. 

"As such, to produce quality vapes, and out of an abundance of caution, HEXO will not develop products that use these."

Diluting agents include propylene glycol, polyethylene glycol and vegetable glycerin – synthetic fluids that are found in the majority of cannabis vape oils and even nicotine e-cigarette liquids currently on both the legal and illicit market.

Health Canada says the liquids are considered safe in many consumer products such as cosmetics and sweeteners but that "the long-term safety of inhaling the substances in vaping products is unknown and continues to be assessed."

Robillard said HEXO is working with a research organization to further study the safety of the products and the occurrence of adverse events with cannabis vapes. 

What's allowed in cannabis vapes?

Under federal regulations, cannabis vapes cannot contain anything that may cause injury to the health of the user or anything other than "carrier substances, flavouring agents, and substances that are necessary to maintain the quality or stability of the product."

Similar to the rules for nicotine e-cigarettes, banned ingredients for cannabis vape oils include added vitamins or minerals, nicotine or alcohol, caffeine and added sugars, sweeteners or colours. 

That includes vitamin E acetate, which has been identified as a "chemical of concern" by the CDC in the vaping-related illness outbreak across North America but has not officially been confirmed as the culprit.  

Health Canada will allow cannabis vaping products to contain up to 1,000 mg of THC, the main psychoactive ingredient in marijuana, per package (a gram of dry cannabis has about 100 mg of THC).

It will also allow flavours, the use of which has been discouraged by the Canadian Paediatric Society in nicotine-based vaping products because of a fear that they will make the products more attractive to young users. 

"There's no question that flavours play an important role in the appeal of vaping products to youth," said Hammond. 

"If you start adding flavours to THC vape oils or other cannabis products, it's probably going to increase their appeal to non-users and young people. That is just common sense."

Making cannabis products more appealing to youth would contradict one of the federal government's main stated reasons for cannabis legalization: to deter use among young people.

Flavouring chemicals such as diacetyl (found in buttery flavours) are also associated with conditions such as "popcorn lung," and pulegone (found in menthol) can have toxic effects when vaped at high levels. 

Flavouring compound raises concern 

One way to flavour cannabis vaping oils is to use a class of organic compounds found naturally in cannabis called terpenes.

Terpenes, which Canadian cannabis companies such as Canopy Growth, Aphria, Aurora and Organigram have confirmed to CBC News they are using in their vaping extracts, are oils that gives cannabis strains their distinct smell and taste. 

But when cannabis is distilled into a vaping extract, the terpenes are removed, leaving an oil that is essentially odourless. 

When those terpenes are added back into cannabis vaping liquids as flavouring, they have the potential to produce toxic emissions when vaporized, including known carcinogens such as benzene, according to a new lab study published in the journal ACS Omega.

"The big take-home message as far as the terpenes go is that people shouldn't add a large percentage of them to the formulations," said Dr. Robert Strongin, lead author and professor of organic chemistry at Portland State University in Oregon.

"We just don't know the full toxic toxicity."

HEXO's spokesperson Robillard says the company is also looking at the chemical stability of terpenes when they are converted into vapour.

"This will allow us to see if our compounds are degraded into potentially toxic products when atomized," she said. 

"Once we are confident in the safety of our vapes and formulations, we will launch our products and conduct additional post-marketing studies." 

Uncertainty over health effects

Health Canada says on its website that "relatively little is known about the pharmacological actions" of terpenes, but it has not restricted their use in the cannabis products that go on sale next week. 

The agency said in a statement to CBC News that it has received 48 applications from licenced cannabis producers to sell cannabis vapes in addition to 746 applications for cartridge-based vaping systems. 

It's unclear how many will be available on the market, because that number includes instances where the same product is sold by two separate licence holders, as well as products that are essentially the same but contain different concentrations of THC. 

"The only thing we can say right now with certainty is that we really just don't have a good understanding about what the health effects are of these products," said Dr. Constance Mackenzie, a respirologist and toxicologist at St. Joseph's Health Care in London, Ont. 

"It took decades to understand what the risks of smoking cigarettes were on the lungs. We probably shouldn't be making the same mistakes again."