3rd alarm at Hattie and Market st. #sffd units on scene pic.twitter.com/qwNXa5hdPe — SF Firefighters 798 (@SFFFLocal798) October 20, 2016

#1020WF1 UPDATE 1 FF INJURED TAKEN TO HOSPITAL NON LIFE THREATENING UNK DISPLACED 4th ALARM pic.twitter.com/Q6gbmb6EtK — San Francisco Fire (@sffdpio) October 20, 2016

Third alarm on Hattie and Market. @Scott_Wiener pic.twitter.com/9NF8C3G2W8 — SF Firefighters 798 (@SFFFLocal798) October 20, 2016

SAN FRANCISCO -- A San Francisco firefighter has been injured while fighting a four-alarm blaze in the Castro District, firefighters said at 1:10 a.m.The firefighter is being taken to the hospital with non-life-threatening injuries as crews continue to fight the fire, which was classified as a four-alarm just before 1 a.m.The blaze was reported at a two-story house at Market and Hattie streets. It was classified as a one-alarm working fire at 12:20 a.m. and upgraded to a second alarm five minutes later.Just before 12:40 a.m., the blaze went to a third alarm.Videos posted to the SF Firefighters 798 Twitter account show thick smoke and flames burning through the roof.No further information was immediately available.