EDMONTON -- Two Edmonton school boards have banned the use of electronic cigarettes on school property over concerns that some students could use the devices to smoke marijuana on the sly.
Police say officers have caught five high school students in the last two weeks with e-cigarettes filled with marijuana oil.
The devices use a battery to heat and vaporize the oil. They mask the smell of the more concentrated drug, which delivers a more powerful high than a regular joint.
"Edmonton Public Schools fully supports the Edmonton Police Service in making the community aware of any dangerous emerging trend," Supt. Darrel Robertson said in a release.
"We will do what we can to not only enforce the restriction of the e-cigarette use around our schools, but to making sure our students, staff and parents are educated of its dangers."
Edmonton Catholic Schools has imposed a similar ban.
Electronic cigarettes, which use the same technology to vaporize nicotine or other materials, are growing in popularity around the world, including with teens. Proponents say they are a safer alternative to tobacco.
A study published in September by the Centers for Disease Control and Prevention in the U.S. suggests that e-cigarette use by high school students to smoke nicotine and other additives more than doubled to 10 per cent in 2012 from 4.7 per cent the previous year.
Police say the trend of using e-cigarettes to smoke cannabis poses another problem. They say it has increased the demand for marijuana and hash oil, which some people are distilling in dangerous home labs.
Fire and police officials in Alberta warn such extraction labs can cause fires and explosions.
Last July, a blast in a lab rocked a home in a Calgary residential neighbourhood as children played outside.
"The demand for hash oil, or cannabis resin, is attributed to the proliferation to the electronic cigarettes," said a recent release from Alberta's Law Enforcement Response Teams.
The Canadian Medical Association has said e-cigarettes are not approved for sale in Canada, but are readily available.
It has been calling for a ban on the sale of nicotine-loaded e-cigarettes to adults until there is solid evidence the devices are safe.
The association has said minors shouldn't be allowed to buy any kind of e-cigarettes.