BOULDER, Colo. (CBS4) – The University of Colorado says they’re still opposed to a large-scale 4/20 marijuana celebration on the Boulder campus despite the recreational use of pot being legal in the state.

CU officials say it’s still illegal to smoke pot in public.

The annual April 20 smoke-out disrupts academics. This year’s celebration falls on a Saturday.

Last spring CU shuttered the campus to outside visitors on 4/20 and Norlin Quad was shut down completely.

Supporters of legalized marijuana light up at exactly 4:20 p.m. in Civic Center Park April 20, 2012 in Denver. (Photo by Marc Piscotty/Getty Images)

The biggest crowds were at Civic Center Park in Denver where thousands lit up to celebrate the smoke out.

PHOTO GALLERY: 4/20 At Civic Center Park 2012

Colorado voters approved Amendment 64 last November. It legalizes recreational use of marijuana up to one ounce for adults. The federal government has not reconciled how they will handle the law in Colorado since pot remains illegal in the U.S.