Photo: The Canadian Press

Public health concerns over vaping have cast a haze over expansion excitement in the cannabis market.

The production and sale of cannabis derivatives — edibles, extracts, topicals and vape products — become legal Thursday on the one-year anniversary of the legalization of recreational cannabis.

Licence holders need to give 60 days notice to Health Canada that they intend to sell the products, so they won't land on store shelves until mid-December.

Some cannabis companies in Canada are anticipating a substantial increase in sales, but Christopher Carlsten said he would have liked to see legalization of cannabis vaping products postponed, or at the very least have significantly more public education about it.

"These products get out there and then we chase our tails trying to figure out what's going on, why we are seeing the toxicity, and then try to regulate retrospectively, which is a dangerous way to do things," said Carlsten, head of respiratory medicine at University of British Columbia.

More than 1,000 people in the United States, and a handful in Canada, have developed a lung ailment apparently linked to vaping.

The Centers for Disease Control and Prevention said last week that the number of confirmed and probable cases of the severe pulmonary illness jumped to 1,299 across 49 states, including 26 deaths.

It has said at this stage "no one device, product or substance has been linked to all cases." But health authorities there are urging people to stop using electronic cigarettes, specifically for products containing THC, or tetrahydrocannabinol, a compound found in cannabis.

Vaping is a new trend and is constantly changing, so Carlsten said experts are just beginning to understand its impacts. Studies are showing short-term effects include swelling and heat damage to the lungs. Long-term, Calsten said, it has also being linked to emphysema.

"Their variability is just too great, the uncertainty is just too great, and I haven't seen any particular product that has clearly been shown to be safe," he said.

Health Canada will not be delaying the legalization of nondried-flower pot products over the concerns. There are regulatory controls for products to lower risks and Health Canada said in an email it will be able to respond to emerging health issues in a timely manner.

Ingredients in inhalable cannabis extracts will be restricted, including vitamin E acetate, which is a focus of investigation in several U.S. cases.

The Cannabis Council of Canada has said illicit vape market in Canada is estimated to be worth roughly $1 billion.