(KRON) — ATF agents said Wednesday afternoon they are still searching for a cause of the Ghost Ship fire that killed 36 people in Oakland last Friday night.

KRON4 News has learned that the fire started on first floor of the warehouse trapping victims on the second floor. There were two internal stairwells from the first to the second floors, neither staircase led to an exit. Smoke from the fire on the first floor traveled up the stairwells preventing party goers from escaping the building.

Jill Snyder, special agent in charge of the San Francisco office of the Bureau of Alcohol, Tobacco, Firearms and Explosives, said it appears the fire started on the first floor “and the occupants were consumed by smoke before they could get out of the building.”

At this time investigators say there is no evidence that the fire was intentionally set. ATF agents say there was no fire alarm system or sprinkler system in the building.

The ATF has not pin pointed a cause, they are examining a number of areas including a refrigerator. ATF experts will be on the scene several more days looking for evidence and walking witnesses through the fire scene.

This is the deadliest fire in the United States since the Station Night Club fire in 2003.

Recovery efforts at an Oakland warehouse fire have ended and the death toll stands at 36, officials said Wednesday.

The news comes a day after Oakland officials declared a local state of emergency due. The Oakland City Council is slated to ratify the state of emergency on Thursday. This will begin the process for state and federal aid.

Tearful family members visited the scene Tuesday and exchanged hugs hours after the founder of the arts collective that used the warehouse stood near the gutted building and said he was “incredibly sorry.”

Meanwhile, the City of Oakland said search and recovery efforts have concluded.

Streets around the scene will begin to reopen over the next few hours.