Smoke from an equipment failure on a BART track prompted transit officials to temporarily close Civic Center Station on Saturday evening.

The station closed for less than 20 minutes at around 5 p.m. because of a blown insulator on the track, which BART said on Twitter can cause a “loud pop sound, a bright flash and a lot of smoke.” The component keeps electricity in the third rail and fails when debris interrupts the path of electricity.

“It’s very contained and not dangerous, it just causes smoke,” BART tweeted, noting that the station is equipped with a robust ventilation system. “We have huge fans for this reason.”

Social media posts showed passengers fleeing the station as smoke filled the area.

BART officials said there was smoke, but no fire.

The station was closed at around 5:55 p.m. and reopened by 6:12 p.m.

A few minutes ago I was on @SFBART pulling into Civic Center, and I heard odd track sounds and saw a fire outside our train car along the wall. Everyone exited ok through another car and left the station. But, uh, I’d expect BART delays for a while downtown. pic.twitter.com/1HcPxfTeRo

— Britta Gustafson (@brittagus) September 23, 2018

Just had to evacuate Civic Center Bart. I think it's a fire? pic.twitter.com/C74GT8v64t

— Matt Kim (@LawofTD) September 23, 2018