One of the biggest problems law enforcers face in states that still enforce cannabis prohibition is whether people are using vaporizers to have a puff of nicotine or marijuana. But now there are special test strips to determine what's inside their vape.

Although many vape pens - small, handheld vaporizers - are marketed as an alternative to cigarettes and intended for use with a nicotine-infused liquid, they have become increasingly popular with cannabis consumers. Oftentimes, the vape pens intended for nicotine are virtually the same as their counterparts designed for marijuana, meaning they can easily be used to vape cannabis concentrates. Additionally, the sweet and often fruity flavors that are placed in vaporizer liquids can cover what would be the distinct smell of cannabis.

That means law enforcers often can't tell what someone is vaping. To combat this, the Denver-based tech company S2 Detection Technologies has re-tooled test strips - which are conventionally used to find liquidized-explosives at airport security - to determine if someone has cannabis concentrates in their vaporizer.

"This is groundbreaking technology," S2's managing director Miles Callahan told CBS.

The new test strips are being leveraged in Colorado schools such as Yampah Mountain High School, where Principal Leigh McGown and his staff had trouble telling what students were vaping.

"It would be very hard for me to know if [a vape pen] has marijuana in it," she said.

Police departments have also begun to use these strips to test for cannabis. And they could catch on in states that have legalized recreational cannabis too. Since none of the legal states allow public consumption, police in those districts are also looking for ways to crack down on people having a puff on the street.

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