Parents of a young woman and man who were killed in the Oakland Ghost Ship fire sued the owner and operators of the converted warehouse Friday for maintaining a “death trap” that caused 36 people to lose their lives.

The suits by parents of 20-year-old Michela Gregory and 23-year-old Griffin Madden, filed in Alameda County Superior Court, were the first since flames tore through the Fruitvale neighborhood building during an electronic music event Dec. 2.

Accused of negligence were building owner Chor Ng, primary tenant Derick Ion Almena and his wife, Micah Allison, event promoter Jon Hrabko, and Joel Shanahan, the performer known as Golden Donna, said San Francisco attorney Mary Alexander, who is representing the two families. Also named in the lawsuits were a next-door business that shared the Ghost Ship’s electricity, and others involved with the show on the night of the fire.

The parents also filed claims against the city of Oakland and Alameda County on Friday, Alexander said, which are precursors to litigation. Although state law provides a broad liability shield for local governments for failing to conduct building inspections, Alexander said the immunity is “not insurmountable.”

Gregory, who grew up in San Bruno, studied child development at San Francisco State University and worked at Urban Outfitters in San Francisco’s Fillmore district. She died alongside her boyfriend, 22-year-old Alex Vega.

“She’s never coming home,” David Gregory, her father, said outside Alameda County court Friday. “We’ll never see her again.”

Madden, meanwhile, had graduated from UC Berkeley last year with a double major in philosophy and Slavic languages and literatures. He had been working for Cal Performances.

The inferno inside the converted warehouse at 31st Avenue near International Boulevard was the deadliest structure fire in California since 1906 and the worst nationwide since 2003.

Survivors and former tenants of the warehouse described it as a labyrinth of furniture, musical instruments, art pieces and reclaimed wood with tangles of electronic wires and extension cords hanging all over the place. The warehouse was home to the Satya Yuga artist collective.

There were no sprinklers in the building, and neither of the two stairwells led to an exit, said officials with the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives, the agency investigating the fire.

“The interior of the 10,000-square-foot Ghost Ship was a death trap, which contained a maze of makeshift rooms, alcoves and partitions,” with inadequate fire safety systems and no safe path from the second-floor music event to the ground-floor exit, the families said in their court filings.

A small refrigerator fire was quickly extinguished by residents a day before the disastrous blaze, according to the lawsuits. The electrical system often released sparks, and circuit breakers were known to blow out because of overloaded electrical lines, the suits alleged.

The lawsuits said Gregory and Madden did not die instantaneously, and instead suffered for “many minutes” and were injured trying to escape.

“They had every gift but the gift of time,” Alexander said at a news conference, standing in front of Gregory’s grim-faced parents.

ATF investigators have yet to identify a cause of the fire. They said it originated near a downstairs wall at the back of the warehouse and spread rapidly throughout the building, overwhelming people upstairs with thick smoke before many had a chance to escape. They have found no evidence of arson.

No city records of fire inspectors ever examining the warehouse have surfaced.

The suits seek unspecified damages for the victims’ pain and suffering before their deaths and for their parents’ loss of their companionship, and punitive damages for allegedly ignoring the dangerous conditions in the building.

Attorneys retained by Ng, the building owner, and Almena, the primary tenant and Ghost Ship leader, did not immediately respond to requests for comment on the litigation.

Chronicle staff writer Bob Egelko contributed to this report.

Kimberly Veklerov is a San Francisco Chronicle staff writer. Email: kveklerov@sfchronicle.com Twitter: @kveklerov