It's becoming a familiar sight in the city -- users call it vaping and say it's a less harmful way to get their nicotine fix.

Many public transit users have seen other riders “smoking” e-cigarettes on the bus, and currently there are no regulations to stop it.

The STM says it's working on a new bylaw that would ban the use of e-cigarettes on its network.

Julien-Pierre Maltais is the manager of vape shop Vaporus on St. Denis. St.

He says having vaping rules for public spaces is a good idea.

“I know that some people who are not vapers and are not smokers are not super happy with second-hand vapour. Now it hasn't been shown that there are any bad things about second-hand vapour, but there is a little residual smell,” he said.

Mario Bujold, Executive Director of the Quebec Council on Tobacco and Health, says while the vapour from e-cigarettes is less harmful than real cigarettes, it's not risk free.

“E-cigarette is not harmless because there is nicotine in it but there are also different toxins that can affect the health of people,” he said, adding it should be regulated as a tobacco product.

And soon people caught vaping by the transit authority could face a $50 fine.

Any new by-law banning e-cigarettes on metros or buses will have to be passed by city council first. The STM says that should happen in the new year.