The organizers of the annual 4/20 Rally at Civic Center Park have lost their attempt to appeal a three-year ban on holding event permits from Denver Parks and Recreation – and that means someone else can apply to have their own event on April 20, 2018.

This comes after the 4/20 Rally organizers failed to clean up after last year’s event on the cannabis holiday, leaving piles of trash in the downtown Denver landmark the next morning.

Denver Parks and Recreation went on to conduct a thorough review of the event, saying they found “substantial violations” of health standards, public safety and security. That’s when they handed down the three-year ban, rescinded the 4/20 rally’s priority event status and charged them a $11,965 fine plus an additional $190 in damages.

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The organizers went on to appeal the ban – something that was denied by a hearing officer on Friday, according to a news release from Denver Parks and Recreation.

Miguel Lopez, the 4/20 rally’s organizer, previously told 9NEWS that cleanup crews encountered issues when a man with a knife started slicing open trash tags. He also said there have been trash issues with the rally in the past, which is why the permit gave them until noon to clean up.

The attorney representing the 4/20 rally organizers says they plan to appeal the latest decision in Denver District Court.

"In that forum, we will have the ability to raise additional arguments, such as First Amendment-related claims, that we could not raise at the administrative level," lawyer Rob Corry wrote in an email to 9NEWS.

"We also will protect the trademark and intellectual property that we built over the years. Whatever the ultimate outcome on the appeal of alleged permit violations, nothing empowers the City to authorize trademark infringement."

The lost appeal means that the April 20, 2018 date at Civic Center Park is now available on a first come, first served basis starting Tuesday.

If you want to apply to hold an event in Civic Center Park on 4/20, head to the Wellington Webb Municipal Building on Tuesday. The doors open at 7 a.m., and people can start lining up at 12:01 a.m. that same day.

The Denver Parks and Recreation Permit Office will start accepting applications starting at 8 a.m.

Euflora, a marijuana company, has been camping out in hopes of being the first in line to get a permit if the 4/20 organizers lost their appeal.

They've been camping in shifts for almost three weeks for a self-admitted publicity stunt.

A spokesperson for the city of Denver says they let Euflora know they can't stay overnight earlier this week, and that facility managers don't want them camping anymore.

As far as Tuesday goes, the city says it doesn't know how much interest there will be in snagging the 4/20 permit or if additional security will be required.