Denver Mayor Michael Hancock’s administration banned the organizer of this year’s 4/20 rally from hosting the event for three years citing a series of violations at the marijuana celebration.

In a letter released Saturday, the administration identified “substantial violations of city requirements” after conducting a review of the 2017 event and imposed $11,965 in fines and $190 in damages in addition to the temporary ban.

“We will continue to ensure that events in our parks are safe, compliant and of high quality,” said Happy Haynes, the executive director of Denver Parks and Recreation in a statement.

An attorney for the Denver 4/20 rally organization called the three-year ban “extreme overkill” on the part of Hancock’s administration and suggested the real explanation is the mayor’s opposition to marijuana. He pledged to get the decision overturned on appeal.

“I think we’ll be able to show … the city’s motivation is to silence the message (of the event) because there aren’t any actual concerns or problems, they are all technical in nature,” said Rob Corry, the group’s general counsel.

The city outlined five concerns in its 11-page letter to the 4/20 event organizers — enough to trigger the three-year ban for future event permits. The violations of the city’s public event policy included four noise complaints, untimely trash removal, limited security guards, unlicensed food vendors and street closures.

Corry disputed each issue and the city acknowledged in the letter it never notified the organizers about the noise complaints.

“None of these things remotely come close to justify revoking the event,” Corry said.

The trash issue received the most attention after piles of rubbish remained in Civic Center Park the morning after the event concluded. The rally attracted several thousand people for the 4:20 p.m. marijuana smoke-in and a concert by rapper 2 Chainz.

“Leaving the trash overnight in the park, even if bagged, is not effective or timely removal of trash from the park,” the letter states.

Corry said the permit issued for the event allowed them to continue the cleanup the day after, and in the end, “we leave the park cleaner than we received it.”

The Denver 4/20 rally organizers have 15 days to file an appeal, and Corry said if the violations are not overturned, then they will also consider taking the case to court.

In the meantime, the controversy surrounding this year’s festival is drawing attention from outside organizations — particularly the Centennial Institute, a think tank of Colorado Christian University, the faith-based school that stood against recreational marijuana sales in its home city of Lakewood.

Jeff Hunt, director of the Centennial Institute, told The Cannabist earlier this year that his organization would become more proactive in “highlighting what’s happening with Colorado in the legalization of marijuana.” The Centennial Institute is planning an Aug. 11 summit on that topic, featuring speakers from law enforcement, education and the medical community.

“It’s not just one thing, it’s a series of things that have gone wrong with this rally,” Hunt said.

Hunt said he walked through this year’s 4/20 event and was disheartened to see cannabis consumed openly in public and in the view of children. He said he and others were concerned about reports of gunshots near the event as well as people pushing down a perimeter fence to gain access to the event.

The Centennial Institute drafted an anti-4/20 petition that was later circulated via email blasts, social media, radio ads, and via CCU’s website. The petition asked Hancock to disallow future 4/20, claiming that the rallies “have become unsafe, flaunting blatant illegal activity, and trashing a national historic landmark, and with incidents of a knife attack and gunshots, the rally is a threat to attendees and the people of Denver.

Police incidents included the arrests of two individuals after at least one shot was heard a block away from Civic Center Park; five arrests at the event; civil citations given to 20 people; and a report at 10:45 p.m. of a man threatening the post-event clean-up crew.

On Wednesday, Hunt delivered the petition and 4,091 signatures to Hancock’s office.

Colorado residents represented about 40 percent of those 4,000-plus signatories, Hunt said. It was unclear how many of those signatures were from Denver residents, Hunt said his office would need more time to tabulate those numbers.

“We felt like it was time to strengthen our voice and tell our mayor there’s a strong contingency of people who are opposed to this rally,” he said, noting that opposition is from people both inside and outside as well as prominent members of the public such as Archbishop Samuel Aquila.