What began as a 10-minute snarl has turned into something more significant Monday morning, when a "medical emergency" on a BART train occurred in a San Francisco station.

Just before 9 a.m., BART tweeted that a medical emergency had been reported at Embarcadero Station.

By 9:11 a.m. that 10-minute delay had been amended to a "major delay" for the entire system, due to an incident on an train in the Embarcadero station.

According to Bay City News, trains were held while emergency officials responded to reports that a man on board an SFO-bound train had a medical emergency.

"Although the man was alert and awake, he wouldn’t get off the train," causing the delay to lengthen. By 9:20, officials say, trains started to move again, though delays were expected to persist as service normalized.