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Marijuana Breathalyzer Under Development To Nab Drivers Taking the 'High' Road


According to the Washington Traffic Safety Commission, fatal crashes involving drivers under the influence of marijuana have risen sharply since Washington voters legalized recreational pot in 2012.

Police agencies around the Northwest are beefing up officer training to detect people driving stoned. And a lab at Washington State University is doing pioneering work to develop a roadside marijuana breathalyzer.

Washington State Patrol Lieutenant Rob Sharpe said driving behavior, coordination, odors, mannerisms and physical cues are some of the factors he uses to establish impairment by drugs.

If you are arrested for DUI, the arresting officer may take you in for an hour-long evaluation by a drug recognition expert. He’d seek a warrant to have your blood drawn at a hospital. The blood work to confirm if you were under the influence of marijuana typically takes weeks to come back from the toxicology lab.

Detecting THC on the spot

Washington State University Chemistry Professor Herb Hill heard about the challenges of nailing drug-impaired drivers during a chance encounter at a reception with now-retired Political Science Professor Nick Lovrich.

“I said, ‘Why don’t we have a breathalyzer for that?’ He said none exists,” Hill said. “I said we can probably make one.”

It’s taken years, but the goal is in sight. Hill and his colleagues are developing a hand-held device that police officers can use to detect THC in breath. THC is the main psychoactive compound in marijuana.

Hill said preliminary field testing with 30 human subjects this spring established that the device can detect THC in breath. Much more testing is ahead to look at potential variations among gender, race, body types and chronic users.

Hill’s team recruits volunteers who buy their own weed, and smoke it at their homes, and then blow into the prototype.

“We had to go through institutional board review,” Hill said. “It took us almost a year to get permission to do this.”

“It wasn’t very hard to find the volunteers,” Hill added with a chuckle. “We have a waiting list of volunteers.”

The human guinea pigs get paid just over minimum wage to smoke their pot.

Hill said the portable device to identify drivers under the influence of drugs may look like an alcohol breathalyzer, but works differently inside. His team is modifying existing sniffers used at airports to detect explosives and by the military to alert to the presence of chemical warfare agents. The technology is called ion mobility spectrometry.

“In the beginning at least this would not be used as evidential information,” Hill explained. “It would be used as screening information to help the officer say he should take a blood sample now.”

‘We need to be accurate’

Tumwater, Washington police officer Jake Yancey said he would be “super excited” to get a tool that he hopes could “drastically speed up” the process of confirming or ruling out a suspect’s possible marijuana impairment.

Sharpe said he’s also excited by the prospect of new tools to help him do his job better. But he says the pot breathalyzer must prove itself highly accurate before he’d adopt it.

“Even if it is a preliminary device, we still need that level of accuracy and reliability for trust and confidence,” Sharpe said. “Regardless where it comes into play in that arrest decision, we’re talking about people’s rights, their liberties and freedoms. We need to be accurate.”

All of which points to it being several years at the earliest before you’d see a roadside breath test to identify stoned drivers.

Sharpe said a pot breathalyzer might not even be the chosen answer. He said other companies and research teams are working on alternative solutions. Those include cheek swabs or a saliva test, a smartphone based eye scan, or analyzing sweat on a person’s skin.

Since legalizing marijuana use for adults, Washington and Colorado have both set legal limits for THC at five nanograms per milliliter of blood. Oregon has not established a legal THC limit beyond which a driver is presumed to be impaired. Neither has Idaho, which does bust stoned drivers even though marijuana has not been legalized there.

Some marijuana activists have expressed fears this technology could lead to unimpaired drivers getting unfairly arrested. They point out that THC persists in the body long after the ‘high’ has worn off. The effects of weed are also different in different people, including between infrequent versus chronic smokers.

As part of the next rounds of human testing of the marijuana breathalyzer, the WSU researchers want to correlate breath readings of THC with simultaneous blood draws and measurements. Among other things, this will help to establish how long THC lingers in breath after initial consumption.

“There is no universal agreement yet on how much THC is impairing,” WSU’s Lovrich told members of the Washington State House Public Safety Committee at a November 20 hearing. “In Europe, it goes from two nanograms to seven.”

Development and commercialization

“We have not been able to do research with marijuana until relatively recently. So we have a lot of testing to do of this impairment - you know with the level of impairment, for what kind of people, and for how long,” Lovrich added.

WSU’s breathalyzer research focuses on detecting smoked marijuana at this point. Hill and Lovrich said they plan to expand their evaluation into edibles and concentrates later.

Lovrich said the potential market for a reliable and portable marijuana breath test could be much larger than just police agencies. Another significant customer base might be employers who, for example, may want to screen heavy equipment operators.

“There’s plenty of demand for it,” Lovrich observed.

Early on, the WSU professors took their idea to instrument maker Chemring, which agreed to pay for the R&D and will have the commercialization rights.

The Chemring-WSU team is by no means alone in trying to perfect a marijuana breathalyzer. Competitors include Lifeloc Technologies of Colorado, which already makes alcohol breathalyzers. Cannabix Technologies Inc. of Vancouver, Canada, has shown off an initial prototype at several conferences. There are reportedly several research teams at work in Europe as well.

Hill said his group’s ability to carry out its research and development project was only possible because Washington state legalized marijuana. Even so, there are no marijuana plants in his lab and no experimentation with volunteers happens on campus.