Maryland police recently hosted a “pot party” to train officer’s field sobriety detection skills and educate marijuana enthusiasts about the effects of the drug on driving impairment.

The Montgomery County Police held one of their “green labs,” where police officers have participants get high and then evaluate their sobriety level.

“Have some fun,” Montgomery County Police Lieutenant John O’Brien told the 10 participants, who brought joints, blunts, edibles, vape pens and a bong to the event.

The “green lab” event took place at the public-safety training academy in the county – a suburban area of Maryland.

Police set up a white tent for participants to smoke out and get high. After the first 30 minutes, participants were sent to classrooms to be evaluated and conduct a variety of field tests, including walking a straight line.

After another 30 minutes, they were asked to repeat the procedures.

29-year-old Tiara Artis, who has a state-issued medical marijuana card, was intrigued about the opportunity to smoke in the presence of police officers.

“Honestly, just for the opportunity to smoke in front of the cops without anything happening to me,” she said. “It’s a little strange, but I’m also used to doing strange things because I’m a strange person,” Artis admitted.

It was Montgomery County’s ninth green lab. Agencies in other areas, including Ohio and Seattle, have similar programs.

“It’s really important that our officers can be able to look at that person and say, OK, I think this is cannabis, and I think it’s affecting them to the point where they can’t operate a motor vehicle safely,” said Officer Jayme Derbyshire, who organizes Montgomery County’s green lab program.

The labs are important for helping officers determine a standard for what counts as marijuana impairment.

While it is illegal to drive while impaired by marijuana, officers are often not familiar with how to assess the degree of impairment under influence of the drug.

Officials hope that the program will give officers greater knowledge and experience to use on the roads.

There are also safeguards to keep things from getting out of hand. Participants are given transportation to and from home, and some have asked to go to bars after. The smoking also takes place outside according to laws prohibiting smoking from inside building.

Participants are paid $60 for their participation.

Officer Derbyshire said that one participant “went into complete shock” after seeing officers showing up to the event in their uniforms.”

 “She was in tears within seconds and went and locked herself in a bathroom stall. It took a few minutes to get her out,” he recalled.

In a classroom, a participant could barely walk in a straight line and had to hold her arms out to steady herself. She also had trouble focusing both eyes on a close-up object and her eyes fluttered, which Officer Kraig Webb noted was a sign of marijuana use.

“Never in a million years would I have imagined that we’d have a tent at the back of the police academy and people are back there smoking,” Webb said.

Some participants even drank alcohol during the event, since mixing marijuana and alcohol is a common practice

Officers were then able to assess the participants’ levels of impairment compared with marijuana use alone.