Concerts get stopped all the time for any number of reasons: The artist is feeling ill, the sound system is on the fritz, the crowd is getting too rowdy and people are getting hurt. But "ventilation issues"?

That's what reportedly happened Wednesday night during the Vancouver stop of [artist id="501686"]Britney Spears[/artist]' Circus tour, when, according to a report by The Canadian Press, workers who were up in the rigging above the stage became ill due to the haze of cigarette smoke at GM Place arena.

A statement on Britney's official Web site explains that "crew members above the stage became ill due to a ventilation issue," and apologizes to fans for the brief pause in the singer's set.

According to reports, Spears abruptly left the stage three songs into the show, blaming the presence of smoke in the arena, and did not return for approximately 30 minutes as the smoke cleared. Extra TV reported that an announcement came over the public address system telling patrons, "The building is awfully smoky. It's become a little bit uncomfortable and unsafe for the performers, including Ms. Spears.

I need you to extinguish all cigarettes — this is a non-smoking building, the show will resume as soon as the air on the stage is clear." It should be noted that Spears has often been photographed smoking cigarettes.

Harvey Jones, vice president and general manager of operations for the company that runs the venue, told the Calgary Herald, "Some people were smoking near the stage and some of the performers took offense and walked off," noting that "this is the first time that's happened."

The paper reported that the disappointed fans at the sold-out arena booed and chanted "Go Canucks go!" before Spears and her backup dancers took the stage again after a nearly half-hour break.

Some fans were reportedly turned off by the drama. "I thought it was a technical error and that she should have just gone along with it," Caleb Asress, 26, of Vancouver, told the Herald. "But she's Britney Spears and a bit of a prima donna, so I guess that's how it goes. Honestly, I thought the beginning was pretty whack. I mean, I didn't come for a circus, I came for her Circus."

Spears appeared to have a sense of humor about the hiccup, bowing at the end of her set and thanking the crowd, telling them, "Drive safe, don't smoke weed and rock out with your c---s out. Peace, motherf---ers."