The station was closed at about 6:20 p.m. after the package was spotted on a San Mateo County District Transit District bus and a sheriff's bomb squad responded to investigate incident, BART spokesman Linton Johnson said.
He said authorities determined the package did not pose a threat and, after combing through the rest of the station, it was reopened at about 8:55 p.m. The package was located off BART property, Johnson said, and BART service at the station was halted due to an "abundance of caution."
BART riders were advised to use parallel bus service to get to Millbrae from the San Bruno and San Francisco International Airport BART stations. The investigation caused delays of up to two hours to Caltrain service.
Johnson said preliminary reports indicate the package was filled with toilet paper.