UC Berkeley Chemist Matt Francis has spent the last year and a half looking for pot, looking for it someplace no one has ever found it before -- in someone's breath.
Hound Labs has developed a breath test that can detect both alcohol, and pot when the person taking it exhales. That's important because while there are already plenty of ways to tell if someone uses marijuana, there isn't a way to know if they smoked pot recently.
"THC resides, its metabolites reside in those media for a long time -- sometimes days, sometimes even a month," explains Francis. "So you cannot use those methods very well to determine if someone has recently ingested marijuana or smoked marijuana. You can't tell how long it's been."
KTXL reports that while Dr. Francis has worked on the problem for a year and a half, Dr. Mike Lynn, the CEO of Hound Labs has been working on this for much longer.
"We have tremendous interest from not only law enforcement, employers, who are struggling with this problem, but also the cannabis industry who knows you can't be driving stoned. Everybody really accepts that," says Lynn.
Lynn argues the breathalyzer will be the best defense for legal pot users who aren't stoned at the time they are driving, but get pulled over anyway.