According to the newshounds at the SF Chronicle, 16th and Mission smells like a urinal:
The B in BART doesn't stand for "bathroom," but it smells like it could at the 16th Street Mission Station.
Commuters wrinkle their noses as they walk across either of the two street-level plazas at 16th and Mission streets, where loiterers have few qualms about using the plazas as an open-air restroom, neighbors and officials say.
"The elevator becomes an easy-access urinal or worse," said Tony Sustak, a Richmond resident who commutes to the station daily. "The real dregs take a dump in public. They're not discouraged by the crowds passing by."
...The plazas are power washed nightly, but the washers are often forced to wash around a group of several dozen people who sleep on the plaza, Allison said.
BART retrofitted and redesigned the plazas in 2003 and 2006 to make them more aesthetically pleasing. The hope was the community would take ownership of the plazas and crime would drop. But, after a brief honeymoon period of cleanliness, the old crowd and habits came back, BART board member Tom Radulovich said.
Sustak called the plaza improvements "a waste of money."
"They just spent $4 million to make a fancier urinal," he said.