Tucson, AZ – A man who was severely burned over 92 percent of his body when his Tucson home exploded last year has filed a lawsuit against Southwest Gas Corp.

According to the suit, a pipeline under Arnold Valenzuela’s duplex was negligently installed and maintained and eventually developed a 2- to 3-inch crack.

The crack allowed natural gas to build up within Valenzuela’s home and when he lit a cigarette on May 27, his duplex exploded, the suit says.

Because of the extent of his third-degree burns, the lawsuit says Valenzuela was kept in a medically induced coma for four months and remains hospitalized.

He’s had about 20 surgeries and his medical bills total more than $3.4 million.

Valenzuela, 44, is expected to have to undergo additional surgeries and his future medical costs will exceed $12 million, the lawsuit states.

The suit _ filed on behalf of Valenzuela, his wife and his parents, seeks unspecified compensatory and punitive damages.

Southwest Gas spokeswoman Libby Howell said that while the company cannot comment on pending litigation, a neighbor of a nearby unit said after the explosion that the smell of gas was apparent, but hadn’t reported it.

Howell also said that the company does routine leak surveys every five years and that area was checked in 2004 with no problems detected.