(CNN) A four-alarm warehouse fire that broke out at Pier 45 in San Francisco has been contained, the city's fire department said Saturday afternoon.
More than 150 firefighters battled the fire that destroyed a quarter of the pier at Fisherman's Wharf, according to Lt. Jonathan Baxter, a public information officer with the San Francisco Fire Department. The warehouse was destroyed.
The blaze was first reported at 4:17 a.m. (7:17 a.m. ET) and was contained to a section of the pier. Flames could be seen in the early morning darkness in photos tweeted by Dan Whaley.
By early afternoon, the blaze was contained.
Firefighters will stay on the scene through Sunday or even Memorial Day to make sure hotspots and active smoldering fires are out, Baxter said at a Saturday afternoon news briefing.
The pier is not far from Pier 39, a popular tourist area.
One firefighter had a severe cut to his hand and was treated and released from a local hospital, Baxter said. No other injuries were reported.
Crews are investigating the cause of the fire but results will not be available for weeks, Baxter says.
The pier was fully evacuated, as were some nearby businesses, the fire department said.
The fire department tweeted a link to live updates.
The fire caused a partial building collapse on the southern part of the pier, spread to two buildings on the pier and was in danger of spreading to a third, fire officials say.
The SS Jeremiah O'Brien, a World War II ship based at Pier 45, would have been lost in the fire without the assistance of fire boats, Baxter said.
Fire boat three did an amazing job and "defended our history, specifically on Memorial Day weekend. It saved that vessel," he said.
"When firefighters arrived, the flames were literally lapping over the Jeremiah O'Brien," he said, CNN affiliate KPIX reported. "They literally saved the O'Brien."
Reporter Reyna Harvey of CNN affiliate KRON tweeted video from the scene.
Several other fireboats also positioned themselves around the wharf and helped fight the fire.
The warehouse contained a large fish processing operation for the northern California crab fleet, KPIX reported.
The fire department is working with the city's Department of Building Inspection and the San Francisco Port Authority to determine the structural integrity of the pier.
It remains unclear whether anyone was in the building, which is sometimes used by homeless people, officials said.
Investigators are looking through surveillance footage in an effort to determine the cause of the fire.