If you have tickets to a 4/20 event For those who have tickets for CU events from 9 a.m. to 6 p.m. April 20, or who are participants in an academic meeting, symposium, conference or other officially sanctioned activity, limited access to the campus will be provided through a registration program. Visitors must register at colorado.edu/april20 beginning at 8 a.m. Monday or by calling the CU information line at 303-492-4636, and they’ll need to check in at the East Campus Administrative and Research Center at 3100 Marine St.

The University of Colorado announced Friday that it will take the unprecedented step of closing the entire Boulder campus to visitors April 20 in an effort to snuff the 4/20 pot smokeout that in recent years has drawn more than 10,000 people to the Norlin Quad.

CU spokesman Bronson Hilliard cited a Boulder campus rule — “Campus Use of University Facilities” — that allows the chancellor to restrict access because of weather, safety concerns or “disruption.” He said the 4/20 closure falls into the latter category.

“This is definitely a measure that is unique,” Hilliard said. “That should be a signal to people that we’re very serious about ending this event on our campus.”

The closure has ignited concerns from the Boulder County chapter of the American Civil Liberties Union, which has asked its lawyers to look into the legality of closing a public college campus.

Only CU students and employees will be allowed on the campus April 20, officials said, and they will be required to show their Buff OneCard identification to authorities.

The grassy area of Norlin Quad also will be closed April 20 to everybody, including students. Hilliard said fish-based fertilizer will be dispersed over the quad that day.

“The gathering disrupts teaching and research right in the heart of the campus,” Chancellor Phil DiStefano said in a statement. “The size of the crowd has become unmanageable, and limits our faculty, staff and students from getting to class, entering buildings and doing their basic work. It needs to end.”

Those ticketed for trespassing could face up to six months in jail and a $750 fine — stiffer than penalties for being busted with small amounts of marijuana.

Judd Golden, chairman of the Boulder County chapter of the ACLU, said he has serious concerns about CU’s tactics.

“It would seem as though this would make the young person wearing a tie-dye shirt on 4/20 more likely to be intercepted by police than somebody who walked on the campus with a coat and tie,” Golden said. “The likelihood of selective enforcement seems significant.”

CU police spokesman Ryan Huff said officers will not engage in profiling.

Golden also said the closure seems to be a violation of people’s freedom of movement in a public place. He said the ACLU has “legitimate concerns about this and what precedent it could set.”

CU freshman Paul Moglewer, a psychology major who said he smokes marijuana daily, had been looking forward to toking up on the quad on 4/20 — especially after seeing videos on YouTube.

He said the university is overreacting by closing the quad and limiting visitor access.

“I think they’re blowing it out of proportion,” he said. “They’re demonizing marijuana. By closing down the campus, they’re making it more of a problem than it would have been. I expect there might be riots.”

CU’s unofficial 4/20 gathering has grown to be the largest in the country on a college campus, prompting Playboy magazine to crown it the nation’s top party school and drawing “Reefer Madness” rankings from the Princeton Review.

Alan Davis, a finance student, said he’s glad the university is finally taking substantive measures to end 4/20 by shutting down the campus to outsiders.

“I think it’s brilliant,” he said.

Davis said the “stoners” will be flocking to CU’s Coors Events Center for a Wyclef Jean concert scheduled for the afternoon of April 20.

Student organizers are spending $150,000 to host the free, student-only, hip-hop concert featuring the former Haitian presidential candidate — who has promoted marijuana legalization — in an effort to keep students from forming a campus smokeout.

Amanda Panepento, a CU freshman who said she doesn’t smoke marijuana, is considering going to the concert. She said many of her peers will likely be smoking before the concert or lighting up in Coors Events Center.

CU officials have said their main priority will be to ensure crowd safety at the concert, perhaps implying that they won’t be sending officers into the crowd to ticket smokers.

City spokeswoman Sarah Huntley said university and city officials have collaborated to make sure CU’s efforts to end the 4/20 smokeout don’t displace the crowd elsewhere in Boulder. The city and university agreed that by announcing the campus closure a week in advance, they could prevent out-of-town revelers from coming to Boulder and spilling into the city when they realized they couldn’t get onto the campus.

Matt Adams, a CU senior studying civil engineering, will be working at his internship April 20 in Lakewood, but he said he suspects 4/20 will carry on in Boulder.

“It’s going to spread out all over the campus and the city instead of just being concentrated on the quad,” he said.

Boulder County District Attorney Stan Garnett has discussed April 20 enforcement operations with campus police officials.

“I’ve assured CU that we will process the cases that they send to us and deal with each one fairly and on a case-by-case basis,” Garnett said.

The Boulder Valley School District — which has an in-service day April 20, meaning students won’t have class — will be sending emails to parents informing them about the 4/20 tradition and explaining that the school district supports CU’s effort to end it. Administrators from Boulder, Fairview and possibly other high schools will be on the CU campus April 20 to discourage students from participating in a smokeout, said Briggs Gamblin, spokesman for the district.

For those who have tickets for CU events from 9 a.m. to 6 p.m. April 20, or who are participants in an academic meeting or other officially sanctioned activity, access will be provided through a registration program. Check colorado.edu/april20 for details.

Contact Camera Staff Writer Brittany Anas at 303-473-1132 or anasb@dailycamera.com.