With legalized marijuana on the horizon, this year's massive 4/20 event in Vancouver is expected to be more party than protest, and officials are doing their best to be prepared.

Thursday's event will be the second in a row held at scenic Sunset Beach, and thousands of pot users, advocates, sellers, merchandise vendors and curious passersby are expected to flood the area.

The last 4/20 attracted an estimated crowd of 25,000 people to the beach.

This year's event will once again be unsanctioned after the park board voted 4-3 against granting a permit, but officials have still been working with organizers to lessen the impact on neighbours. Portable toilets were already being set up in the area on Wednesday.

And for the first time ever, board chair Michael Wiebe said the city will be trying to get some of the costs back after the event.

"Things are changing. We're also going to be calculating all the costs we have and creating an invoice," Wiebe said.

Between policing and other expenses, last year’s 4/20 cost taxpayers nearly $150,000.

But advocates, including Jodie Emery, insist organizers are paying for much of the cleanup and other costs themselves.

Emery also claimed that despite the pending pot legalization, the protest aspect of the event is as important as ever.

"Legalization is not going into effect for a while, and people are still going to be arrested for non-violent, peaceful activities. That's something we need to protest," she said.

As always, police will be on hand to ensure public safety, and the emergency department at St. Paul's Hospital is readying extra coverage of nurses and doctors over the course of the day and night.

B.C. Emergency Health Services said it's dispatching 21 paramedics to be on site at 4/20 as well.

Last year, 31 people were treated at the beach, all for minor ailments. Dozens more were treated in hospital for symptoms ranging from upset stomachs to anxiety, mostly from taking edible marijuana products.

It's unclear how much the 2016 event racked up in health costs, but it cost $99,400 in policing, $24,000 in park board services, $13,600 in street and sanitation work, $6,900 for firefighters' services, and $4,100 for traffic management, according to numbers from the City of Vancouver.

A large portion of the price tag went to cleanup, as the event left several piles of garbage that had be carted away from Sunset Beach.

The Vancouver Police Department warned there could be traffic disruptions during Thursday's event, particularly along Beach Avenue between Broughton and Burrard streets.

The force warned that officers, including drug recognition experts, will be out watching for impaired drivers throughout the day.

With files from CTV Vancouver's Nafeesa Karim and Penny Daflos