Kermit J. Kyle, of San Gabriel, was taken into custody late Tuesday, said Los Angeles County Sheriff's Deputy Mark Bailey. Authorities declined to reveal a motive.
The blast Sunday ripped through a two-story apartment building, sending a huge fireball over this bedroom community about 15 miles east of Los Angeles. The explosion destroyed an eight-unit apartment complex and damaged nearby buildings.
Two apartment residents were hospitalized, including a 33-year-old man who suffered second-degree burns on his back. In addition, two people driving by in a car and another person suffered minor cuts.
"We're leaning more towards a suspected bombing at this point," city fire Deputy Chief Vince Kemp said after the blast, which blew out the building's roof and most of its exterior walls.
CBS station KCBS-TV in Los Angeles reports that police were at first fearful that there could be another explosion and evacuated the surrounding area.
"All of a sudden, we saw a big orange explosion inside our house," said Michael Bonales, who lives across the street. "The windows blew out. I thought it was some kind of major disaster or the world was ending or something."
Gloria Ramirez said she and her daughter grabbed a basket of clothes before running out of their home. "I have no windows in my house, in my place. Everything's damaged," she said.
Authorities evacuated the surrounding quarter-mile radius while they searched for possible additional explosive devices before entering the wrecked building to look for more victims. They found none.
Arson and explosives detectives resumed their investigation early Monday, a sheriff's spokesman said.
"We do have information that the rear of the building has sustained the major damage and that is a possible (bomb) location," Kemp said.
The American Red Cross set up an emergency shelter in Alhambra High School's gymnasium for people who were forced to evacuate the apartment building.
"We came outside and saw the apartment blown up like in the movies," said Bonales.