BENICIA, Calif. (KRON) — The cause of Saturday’s commercial fire at the Benicia Port appears to have been unintentional, Benicia Fire Chief Josh Chadwick said in a statement released Tuesday.

“While the fire investigation is still open and ongoing, preliminary findings indicate that the origin of the fire was on or near the lower portion of the coke conveyor belt system near the base of the silos,” said Chief Chadwick. “The fire appears to be unintentional in nature. Electrical and mechanical causes have not yet been ruled out.”

Earlier in the week, officials with the city of Benicia and representatives of local and state agencies toured the fire site to assess fire damage and plan cleanup efforts. The fire broke out Saturday at 12:20 p.m. near the Amports terminal at the base of a silo used for an oil refining byproduct known as petcoke.

After 24 hours of battling the fire, officials announced it was largely extinguished by Sunday morning, although small pockets of fire remained until about 12:24 p.m. Sunday. The fire in Benecia was one of two significant fires in the region over the weekend. To the south in San Jose, a five-alarm fire erupted in a Home Depot and gutted the retail establishment.

That fire remains under investigation. Some of those who evacuated the building have questioned whether the store’s sprinkler systems went off.