Vaper City in downtown Vancouver has been getting questions from some of its customers wondering if vaping is still safe.

“They’re just like they’re concerned about it,” said Muhammad Tasleet, Vaper City manager.

The mysterious lung illness that has struck down and killed people who vape is now hitting closer to home – just last week a case was confirmed in Ontario and that has health officials across the country on high alert.

“Pretty alarming,” said Dr. Milan Khara, who heads up Vancouver General Hospital’s Smoking Cessation Clinic. “There are things in vapor that we don’t fully to understand and this cluster of cases in the United States is really giving us pause for thought.”

Vaping has become popular among people who are trying to quit smoking. It helped Tasleet, who used to smoke and now doesn’t even vape anymore.

Cigarette smoke contains more than 7,000 chemicals, while vaping nicotine has about 8 different chemicals.

“In theory, it should be less harmful, but it’s not the case that it’s not without harm at all, that it’s without risk, there are things in vapor that we need to be concerned about,” said Dr. Khara.

In many cases those who have fallen ill have vaped both nicotine vape oils and also THC and products containing other cannabis products like CBD. There’s some suggestion that some of the vape oils in question have been products bought on the street that may have been contaminated.

“We do receive calls from people like, 'hey, we have the liquid that is CBD-infused,' and we simply say, 'No, we are not interested in it.'” explained Tasleet. “They are easy to make and everyone can make in their basement and everyone can make in their apartment. Don’t buy those ones, just ask them where it’s made, where the lab is.”

Health Canada told CTV News it randomly tests nicotine vape oils. The agency says cannabis vape pens will be highly regulated and controlled when they become legal on Oct. 17.

“There will be several regulatory controls in place to help safeguard the health of Canadian consumers and to enable Health Canada to respond to emerging health issues in a timely manner,” Health Canada said in an email to CTV News.

However, the agency is on high alert and working with American health officials in trying to determine what’s causing people to become ill from vaping.

In Canada, vitamins are not allowed in vape products. However, vitamin E acetate – a thickener found in some cannabis vape oils – has been linked to the strange lung ailment.

It’s basically grease that aerosolizes with high heat, cools and then condenses inside the lungs, coating them with oil.

Other things that have cause for concern are the flavours in vape oils. The oils contain propylene glycol, glycerin, benzoic acid, nicotine, and flavourants.

“And the flavours themselves may carry health risks above and beyond being attractive to youth,” said Dr. Khara.

The bright packaging and fruit flavours, like honeydew melon, mango and bubble gum kiwi strawberry are attractive to teens.

Even teenagers who have never smoked cigarettes are now trying vaping, raising concerns about increased nicotine use among youth. And some of the e-cigarettes look like USB drives and can easily hide in a pocket, out of sight of parents and teachers.

While the legal age for vaping is 19, it hasn’t stopped teens getting their hands on the products.

Proposed bans on vape products are now focused on flavoured products. And Health Canada has already addressed that issue with cannabis vaping rules.

“The use of sugars, sweeteners or sweetening agents as ingredients in cannabis vaping products will not be allowed.” Health Canada said.

The agency urges parents to talk to teens about the risks of vaping and continues to work with American health officials to get to the bottom of the recent health scare. In the meantime, it's urging people who vape to monitor themselves and report any adverse effects, like shortness of breath, chest pain and coughing and to seek medical attention.

The U.S. Centers for Disease control says until more is known, “you should consider refraining from using e-cigarette or vaping products.”

“I think we are aware that as this vaping story unfolds that it may be that vaping carries risks that we don’t fully understand,” said Dr. Khara.