One day after a two-alarm fire displaced 11 residents, a grass fire that sparked less than a block away scorched an acre of land and injured a firefighter Monday.

North County Fire Authority responded to a grass fire at 6 a.m. Monday at San Bruno and Thomas avenues, a few hundred feet away from an apartment complex that was torched at 45 Joy Ave. Sunday. Firefighters took several hours to make sure the fire would not spread.

Battalion Chief Tony Maffei said the cause of the fire is still under investigation and is unrelated to the apartment complex fire. He said he does not suspect arson.