OAKLAND, Calif. — More than six months after the Dec. 2 blaze at the Ghost Ship warehouse in Oakland that killed 36 people, the Oakland Fire Department released a 50-page report, dated March 18, late Monday on the city’s website.

The cause of the nation’s deadliest structure fire in more than 14 years could not be determined because of fire damage.

About 52 firefighters battled the blaze at the 2-story warehouse, an artist collective with a labyrinth with makeshift hallways and live-work spaces constructed of “pianos, organs, windows, wood benches, lumber” and innumerable other scavenged items.

Most of those who died were trapped upstairs, where the party was underway. It took firefighters days to dig out all the bodies.

All 36 died of smoke inhalation, their lungs clogged with smoke and soot, according to autopsy information in the report provided by the coroner’s office.

The warehouse had no sprinklers and an ad hoc electrical system of power strips and extension cords that drew “electricity from the body shop next door,” according to Max Harris, the self-described “creative director” and second-in-command of the Ghost Ship. Harris, 27, and Derick Almena, 47, who leased the warehouse from the owner, were charged this month with 36 counts of involuntary manslaughter. Prosecutors say the men knowingly created a fire trap in a building not licensed for housing or entertainment.