What in the?! Who is defecating with such frequency on our BART station escalators that, after it oozes down and gums up the machinery, it is causing them to break? Well, according to SF Chronicle, the homeless are to blame. It seems that, in the middle of the city's white-hot mid-Market area, residence-free denizens have been pooping en masse at the bottom of the stairwells at the BART Civic Center station after it closes. And it's now an even bigger issue.

The Chronicle reports:

All those biological excretions can gum up the wheels and gears of BART's escalators, shutting them down for long periods of extended repairs, increasing station cleaning costs and creating an unpleasant aroma for morning commuters.

Five of the nine escalators that weren't working at BART stations on Wednesday were in downtown San Francisco, said Jim Allison, a BART spokesman. While there are many reasons a BART escalator can break down, the beating they take at night is among the most acute.

Even a hazardous-materials team had to be called in to deal with the stinky situation.

The problem, among so many, is that authorities cannot cite the mad poopers unless they're caught in the act. "Bottom stairwell of Civic Center station" is a beat no cop would want. Also, the lack of public restrooms open late in the area is also to blame.

Sorry to ruin your breakfast/lunch.