SF signs up sponsors for 4/20 weed fest in Golden Gate Park

San Francisco’s favorite pot party has finally gotten the official go-ahead from the city.

The Recreation and Park Department is issuing its first-ever permit for next month’s 4/20 marijuana-smoking blowout on Hippie Hill in Golden Gate Park. For years, the event has drawn tens of thousands of weed aficionados to the park and the city has been stuck with the costs, including paying for hauling away tons of trash that the crowds leave behind.

This year, a handful of Haight Street merchants and local cannabis businesses, including the Diamond Supply Company, Cookies SF and the Green Door dispensary, have taken on the job of sponsoring the festival. They will pay for fences and gates, portable toilets, and traffic and emergency plans for the formerly unsanctioned celebration April 20. The permit fee will also help cover policing and trash-removal costs.

“The way it used to be was a free-for-all,” said Alex Aquino, a sponsor who owns Black Scale, a clothing shop on Haight Street. He declined to say how much the sponsorship cost, only that it was “very expensive.” A typical permit for an event of 4/20’s size costs around $100,000, according to Rec and Park figures.

Alex Aquino stands for a portrait at the Black Scale. Alex Aquino stands for a portrait at the Black Scale. Photo: Santiago Mejia / Santiago Mejia / The Chronicle Buy photo Photo: Santiago Mejia / Santiago Mejia / The Chronicle Image 1 of / 30 Caption Close SF signs up sponsors for 4/20 weed fest in Golden Gate Park 1 / 30 Back to Gallery

“I’m just a guy in the neighborhood trying to do my part,” Aquino said. “The party’s not going anywhere. It’s not going away. I think building infrastructure will keep it safe and clean. It will preserve the park and keep our neighbors happy. How can we not benefit from that?”

Last year, revelers left behind 22,000 pounds of trash, including a children’s wagon loaded with a keg. The garbage pickup alone cost the city $50,000, and with police, transit and other expenses, the total bill came to more than $80,000.

The marijuana party was also a buzz kill for nearby merchants and residents whose streets were crammed with cars with out-of-state plates and whose doorways were used as bathrooms.

“This is an event that I, like most people in the neighborhood, dread every year,” said Ted Loewenberg, president of the Haight Ashbury Improvement Association. “When it’s all done, there is an enormous amount of garbage, and there are traffic jams. I’m delighted that somebody has come forward to sponsor this event and take some responsibility for keeping it organized and absorb the cost so it doesn’t impact taxpayers.”

Although it is technically still illegal to light up in public parks, California voters’ decision to legalize the recreational use of marijuana has made city officials change their stance.

“Love it or hate it, the 4/20 festival is not going away, and it has a significant impact on our city, on our district and on the park system,” said Board of Supervisors President London Breed, whose district borders Golden Gate Park. “Every year, the event leaves the park and surrounding neighborhood a mess. It’s not safe to allow people to party in the park without adequate security, facilities and medical aid.”

Breed acknowledged that the mass smoke-in was still illegal and said City Hall “didn’t want to sanction the event.” But she added that it was “irresponsible to ignore it.”

Rec and Park officials agreed.

“We are trying to be creative and nimble and understand that people are going to keep doing this no matter what,” said department spokeswoman Sarah Madland. “The goal is to try and see if we can increase public safety. It’s not about saving money in year one. The hope is that if this provides the necessary stability, then there may not be as much of a burden to all of the city departments.”

Violence and use of hard-core drugs have also plagued the event. Last year, eight people were arrested, and two teenage boys were robbed by a man wearing brass knuckles. In 2015, an assailant smashed a bottle on a park ranger’s head, and two groups of men violently robbed people in Golden Gate Park. Five people were arrested that year. In 2014, 11 people were arrested.

Madland hopes the sponsorship will lessen that kind of trouble.

“The intention is that the actual event will be controlled by the organizers,” she said. “No one under 18 will be allowed in. It’s exciting that this is happening and we can manage the impacts on the neighborhood and the park.”

Lizzie Johnson is a San Francisco Chronicle staff writer. Email: ljohnson@sfchronicle.com Twitter: @LizzieJohnsonnn