We're getting reports via a perturbed BART rider that "something has been released" causing passengers to start coughing on the lead car of a BART train at West Oakland Station. Another rider says that "noxious fumes" have caused a BART service delay, and posted a picture of passengers waiting on the platform by a stalled train.

We'll update you as we learn more.

Update: BART now says it's "recovering" from a 15-minute, system-wide delay due to "police activity" at West Oakland.