We all know that BART elevators (and escalators!) are frequently used as restrooms. According to a regular BART rider, the trains are also at risk, and he has video of one such incident as proof.

Of course it's KRON 4 that brings us this tale, including a blurry video clip of the incident. Don't say we didn't warn you:

BART rider Allen Nunley tells KRON 4 that he commutes from Pittsburg to BART's Civic Center Station five days a week, where he regularly sees the woman depicted in the video above.

"She took her pants down,” Nunley tells KRON. “I don’t know if she did No. 1 or No. 2, but she did wipe. When she got done wiping, she put the issue down, pulled her pants back up, Went back to her seat, and laid down. I was like, ‘Oh no! This is crazy.’ Everyone there next to me was like, ‘Oh my God! She’s really going to the bathroom. This is crazy.’”

It doesn't appear that Nunley took the video to shame the woman, who is clearly troubled and in need of help. Instead, Nunley says that he's hopeful that it will serve as yet another wake-up call to BART management, sending it to them on Thursday. They have yet to respond, he says. KRON 4's outreach was met with similar silence, they report.

"We can get sick from it,” Nunley tells KRON in reference to the incident he recorded.

“As BART riders, we pay a lot of money to ride BART, and it’s just really ridiculous that BART staff cannot do anything about that. Everyone on the train is just covering their mouths and everything. They just can’t deal with it either. This particular time I just had enough.”

Another passenger who spoke to KRON 4 took a more pragmatic approach, however. "BART already does a good enough job of cleaning up the cars each night before they're put out the next day."

"I don't think there's anything you can do to clean up better or prevent the problem," the rider said. "I think it's just part of the nature of living in a city that has large population of homeless people who are mentally ill."

Related: BART Says Randomly Beaten Rider 'Out Of The Ordinary,' Apparently Forgetting Similar Attacks Last Month