Evan Aviles, 21, and his girlfriend Lexie Huston, 22, live at the apartment at 3624 Silver Oaks Way where the explosion happened around 5 p.m. on May 21, Livermore police Lt. Ava Garavatti said.
Hospital officials have told police that Aviles and Huston are scheduled to undergo various surgeries, Garavatti said.
On Thursday, the third victim, Paul Lom, 35, of San Jose, succumbed to his injuries, police said.
Garavatti said there is evidence the explosion was related to drugs and that police will release more information after conducting further interviews.
The exact cause of the fire is still under investigation, according to Garavatti.