Near the end of Thursday’s BART Board of Directors meeting, the transit system’s elected leaders found themselves in the unusual position of staring at something not on the agenda: a fresh puddle of urine.

BART directors usually meet twice a month in a clean, quiet, windowless board chamber in Oakland, but this time they took a field trip to Powell Street Station to view its “challenges” — homeless people sleeping in hallways, intravenous drug users, rundown conditions, dirty floors, and elevators and escalators used regularly as restrooms.

As an elevator door opened, a BART staff member observed something. “You can see, there’s fluid at the bottom,” said Paula Fraser, assistant chief transportation officer for BART’s San Francisco and Peninsula lines. “It often includes a tissue, too.”

Maintenance workers try to clean up elevators as quickly as possible, Fraser said, but the problem is so pervasive that they’d need to post a janitor at the elevators full time to ensure their cleanliness.

“Here at Powell Street, just about every time the elevator goes up to the street, unfortunately, it is used as a restroom,” she said.

If the directors were appalled or shocked, they didn’t show it.

Powell Street Station is the third-busiest of the system’s 46 stations and may be its most troubled. It’s the gateway to San Francisco for tourists, shoppers and day trippers, but it’s home to an increasing number of society’s dispossessed, who use it to sleep and shoot up, and to relieve themselves on its elevators and escalators, in part because its restrooms have been locked.

Once a showpiece station, with a giant illuminated map, it’s now a dreary place. Dirt streaks its white-and-gray floors, and its ceiling has been missing for four years. Sections of the station concourse are boarded off with painted plywood, and its elevators and escalators are frequently broken.

Thursday’s tour was attended by 50 or so people, who strolled out of the station’s Hallidie Plaza exit past a panhandler on crutches and up the escalator to Market Street, where they viewed the nearby Decaux public toilet and heard about city plans to move more portable Pit Stop toilets near BART stations.

Then they heard from merchants and tourism experts who said Powell Street Station’s deteriorated conditions are a drag on business.

Travel-industry representatives said a lot of visitors see San Francisco for the first time after taking BART from the airport to Powell Station and are disconcerted by the experience. Jessica Lum of the Hotel Council of San Francisco said guests often comment on the station’s uncleanliness and lack of feeling of safety, and on the fact that they don’t see police officers at the station.

And it’s not just tourists. Claude Imbault, director of strategic initiatives for the Union Square Business Improvement District, said employees often avoid Powell Street Station. Macy’s workers, he said, have nicknamed the station “the Toilet” because of the pervasive odor.

“What’s happening in Powell Street Station is having an economic impact on San Francisco,” Imbault said. “We can do better.”

Later in the tour, they strolled down a hallway lined with people sprawled out and sleeping on the floor, and then gathered in the center of the station to listen to a talk about homelessness.

Experts discussed plans that BART has to work with Muni and the city to help homeless people find the help they need, and eventually find a better place to sleep. But they made it clear homeless people can’t just be thrown out of the station.

“We’ll talk with them, work with them,” said Scott Walton, manager of emergency outreach and services for the city’s Department of Homelessness and Supportive Housing.

Another speaker was explaining a program to help keep low-level drug offenders out of jail, when a BART rider interrupted.

“What are you going to do for the riding public?” shouted Tom Selhorst, an El Cerrito resident who rides BART to Powell Station daily. “This is about public safety. Crimes are happening more and more on trains.”

Police Chief Carlos Rojas told him BART’s police department plans to increase its visibility in stations and on trains. Just days ago, BART put up a sign identifying its Powell Street police substation, which has been hidden inside the station for years. Rojas said a phone will be installed outside the station to help riders summon assistance when they need it.

Selhorst said later that he and his co-workers talk about how unsafe BART feels with aggressive panhandlers on trains and recent stories of robberies by gangs of youths.

“It feels scary to be on BART, and it used to feel safe,” he said. “There seems to be a general laxity in enforcing the laws and rules. There needs to be structure. The rules don’t seem to matter.”

The tour, led by Tim Chan, planning manager, also offered hope for the future. Within weeks, BART will start installing a suspended metal grid ceiling. It should be done by Thanksgiving, he said.

A station overhaul will follow in the next couple of years. It will include newly designed restrooms, a reconfigured concourse that moves ticket machines from the center of the station to its walls, higher barriers to the paid area of the station and a new elevator in the Muni Metro area.

That will allow BART to restrict the existing elevator, which stops at the Muni and BART levels, to BART patrons only, and sequester it inside the paid area of the station. It will help combat fare evaders and those who urinate in it.

“That will really help,” Fraser said.

Directors said the nearly two-hour tour gave them a close-up look — perhaps too close in some cases — at problems they usually only confront in emails, reports and discussions.

“This was important to do,” said Director Joel Keller of Brentwood. “Homelessness is a serious problem that impacts society in general and has a huge impact on BART. We simply have to improve the conditions in our stations. It would be a shame to let our stations become de facto homeless shelters.”

Michael Cabanatuan is a San Francisco Chronicle staff writer. Email: mcabanatuan@sfchronicle.com Twitter: @ctuan