north to the San Fernando Valley. Residents in some parts of the city bitterly opposed the subway. A 1985 methane explosion at a Ross Dress for Less clothing store near Fairfax gave Rep. Henry Waxman, who represented the Fairfax District, a reason to derail the project that was opposed by his constituents by prohibiting tunneling in an alleged "methane zone" west of Western on Wilshire. After some political wrangling, a new route was chosen up Vermont Avenue to Hollywood Boulevard. The groundbreaking for the first segment of the subway was held on September 29, 1986, on the site of the future Civic Center/Grand Park station. Today's B Line was built in four minimum operating segments: MOS-1, consisting of five stations from Union Station to , opened on January 30, 1993, as the Red Line. (At this point, the line's operator was still the Southern California Rapid Transit District). MOS-2A, consisting of three stations from to , opened on July 13, 1996, although only one station on this section () is on today's B Line. MOS-2B, consisting of five stations from to , opened on June 12, 1999. MOS-3, extending the Red Line from to , opened on June 24, 2000. On June 22, 1995, during the construction of MOS-2B, a sinkhole appeared on Hollywood Boulevard, barely missing several workers and causing damage to buildings on the street. Subway construction was delayed during the investigation and repairs of the sinkhole. The contractor on that segment project was replaced, and because of the perceived mismanagement of Red Line construction, in 1998 voters banned the use of existing sales taxes for subway tunneling. Construction of MOS-3, by comparison, proceeded with relatively few issues. Tunneling from North Hollywood for the subway started in 1995. Workers dug under the Santa Monica Mountains using tunneling machines. Work progressed an average of daily, performed by work crews round-the-clock six days a week. Original proposals for the subway system included expansions east from Union Station to East Los Angeles and west from North Hollywood towards the Warner Center transit hub in the San Fernando Valley. Barred from subway tunneling, Metro turned to other types of mass transit. In the San Fernando Valley, residents passed a law in 1991 mandating that any rail line in the area be built underground, so Metro built a busway (now the G Line) from North Hollywood to Warner Center, which opened on October