GRAND JUNCTION — In two years of work as an undercover officer with a drug task force, Mike Dillon encountered plenty of drugs. But nothing has surprised him as much as what he has seen in schools lately.

Dillon, who is now a school resource officer with the Mesa County Sheriff’s Department, said he is seeing more and younger kids bringing marijuana to schools, in sometimes-surprising quantities.

“When we have middle school kids show up with a half an ounce, that is shocking to me,” Dillon said.

The same phenomenon is being reported around Colorado after the 2010 regulation of medical marijuana dispensaries and the 2012 vote to legalize recreational marijuana.

There are no hard numbers yet because school disciplinary statistics do not isolate marijuana from general drug violations. But school resource officers, counselors, nurses, staff and officials with Colorado school safety and disciplinary programs are anecdotally reporting an increase in marijuana-related incidents in middle and high schools.

“We have seen a sharp rise in drug-related disciplinary actions which, anecdotally, from credible sources, is being attributed to the changing social norms surrounding marijuana,” said Janelle Krueger. Krueger is the program manager for Expelled and At-Risk Student Services for the Colorado Department of Education and also a longtime adviser to the Colorado Association of School Resource Officers.

Krueger said school officials believe the jump is linked to the message that legalization (even though it is still prohibited for anyone under 21) is sending to kids: that marijuana is a medicine and a safe and accepted recreational activity. It is also believed to be more available.

Marijuana that parents or other adults might have kept hidden in the past may now be left in the open, where it is easier for kids to dip into it to sell, use or, in some cases, simply to show off, said school officials and law enforcement.

“They just want to be cool,” said Dillon of some of the younger students he has seen with pot at school.

Krueger, who has been an adviser to resource officers across Colorado for 17 years, said she has heard many stories from officers about kids bringing pot to schools.

One that an officer related at a meeting recently involved a student dropping a small baggie of marijuana from his pocket as he was walking down a school hallway. The school principal was walking past the student at the time and picked up the pot. He asked the student if it belonged to him. The student immediately admitted it was his and reached out to take it back from the principal.

What struck Krueger and the officer about this incident was the fact that the student didn’t seem to realize that there was anything wrong with having the pot or that there would be any disciplinary consequence for it. The officer said the student acted like having marijuana was an ordinary thing and no big deal.

Jeff Grady, a Grand Junction school resource officer who has spent 25 years working in schools, tells a story about sitting in his car at a park near Grand Junction High School one day watching groups of kids through binoculars because they come to the park to smoke on lunch breaks.

“Kids are smoking before school and during lunch breaks. They come into school reeking of pot,” he said. “They are being much more brazen.”

He said school officials call him and he talks to the kids, but it is a little more difficult now to cite them if they aren’t caught in the act. They can say that they were around an adult medical marijuana user and weren’t smoking themselves, Grady said.

The best quantifiable evidence the state has yet to indicate that marijuana is a significantly growing problem in schools comes from the 2012-13 report that documents why 720 students were expelled from public schools across Colorado.

For the first time, marijuana was separated from other drugs when school officials were asked to identify the reason for students’ expulsions. Marijuana came in first. It was listed as being a reason for 32 percent of expulsions.

National statistics also point to marijuana being more prevalent in schools.

The National Institute of Drug Abuse found that marijuana use has climbed among 10th- and 12th-graders nationally, while the use of other drugs and alcohol has held steady or declined.

Marijuana is the only drug showing steady increases, the ” Monitoring the Future” study showed.

Christine Harms, director of the Colorado School Safety Resource Center, said the increase of marijuana in schools is not just a problem for school resource officers to grapple with. It was discussed when school psychologists met in Vail last week.

“They are seeing more incidents of kids smoking and thinking it is a safe thing to do. More kids are saying they are getting it from their parents,” Harms said.

She said counteracting the message legalization is sending to kids is especially difficult now because federal grants for drug abuse prevention have been cut. She and other officials urge parents to take the lead with help from the Speak Now Colorado program that guides parents in how to talk about substance abuse.

“They need to know how destructive it is to the adolescent brain,” Harms said.

Nancy Lofholm: 970-256-1957, nlofholm@denverpost.com or twitter.com/nlofholm