NEW YORK (Reuters) - New York City prosecutors indicted two men on Wednesday in connection with an explosion at a home last month that killed the city's highest ranking fire official to die in the line of duty since the Sept. 11, 2001 attacks.

Battalion Chief Michael Fahy died after he was hit in the head by debris from the blast at a residence in the borough of the Bronx where he and other firefighters were responding on Sept. 27 to reports of a gas leak.

"Chief Fahy responded to a building that turned out to be a time bomb. These defendants allegedly were growing marijuana and kept flammable substances on the premises," Bronx District Attorney Darcel D. Clark said in a statement.

"Chief Fahy ordered residents out of the building - including one of the defendants - and saved their lives. He was mortally injured when the force of the explosion blew off the slate roof and it struck him," Clark said.

Garivaldi Castillo, 32, and Julio Salcedo, 34, both of New York City, were indicted on charges of first degree assault, second degree assault, and first degree criminal possession of marijuana. The statement said they were arraigned on Wednesday and are due back in court on Nov. 23.

If convicted, they could face up to 25 years in prison, Clark's statement said.

(Reporting by Daniel Wallis; Editing by Bernard Orr)