SAN FRANCISCO (KRON) — Firefighters are responding to a building fire near Alamo Square in San Francisco, according to the San Francisco Firefighters union. The one-alarm fire broke out at 815 Hayes Street.

San Francisco Fire Department units are reportedly on the scene.

The inbound and outbound 21 Hayes bus line is blocked at Hayes and Webster streets due to SFFD activity, according to SF Muni. Buses are being rerouted around the affected area via Grove Street.

This is a developing story. Check back for updates.