UPDATE, 1:45 p.m.: According to SFFD, PG&E has resolved the issue and fixed the main break. No injuries were reported.
San Francisco Fire Department tweeted at 1 p.m. Wednesday afternoon that two blocks of Townsend Street between 5th and 7th streets have been closed in both directions due to a three-inch gas main leak at a construction site. No evacuations or orders to shelter in place have been issued. PG&E is on the scene, and people are being asked to avoid the area. Repairs are estimated to take 30 minutes.