BERKELEY, California -- UC Berkeley Chemist Matt Francis sees pot differently than most people.
“This is the THC molecule,” Francis says, drawing the molecule on a whiteboard.
Francis has spent the last year and a half looking for pot, looking for it someplace no one has ever found it before-- in a marijuana user's breath.
"We had to develop some new chemistry that can actually be done. It was not obvious when we started that we could tag this,” explains Francis.
Meanwhile, it can be obvious to a street cop when somebody's driving stoned.
"I think for most of our officers, impaired is impaired. They can see that based on their training and experience,” says Sergeant Davis Dowty.
But according to Sgt. Dowty with the union that represents Highway Patrolmen, being able to make an arrest, and being able to get a conviction are two different things.
"Because they don't have a tool, like with alcohol, it's very difficult for them to say 'OK. All these things that you saw and you may be right, officer. But we need to be able to convince a jury,'” says Dowty.
But Hound Labs may have an answer. It’s a breath test that can detect both alcohol, and pot when the person taking it exhales. That’s important because there are already plenty of ways to tell if someone uses marijuana.
But to tell if they smoked pot recently, if they are stoned, breath is much better than urine or blood.
"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."
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.
Lynn argues the breathalyzer will be the best defense for pot users who aren't stoned at the time they are driving, but get pulled over anyway.