SAN FRANCISCO (NYTIMES) - About 150 firefighters battled a four-alarm blaze that destroyed a quarter of the structures on Pier 45 in San Francisco early on Saturday morning (May 23), the authorities said.

One firefighter had a severe cut to an arm, said Lieutenant Jonathan Baxter, a spokesman for the Fire Department.

He said the firefighter was taken to a hospital and was expected to recover.

No other injuries were reported.

Officials were investigating the cause of the fire, which was reported around 4.15am at a warehouse.

The fire broke out at Fisherman's Wharf, a commercial tourist district with attractions, including restaurants and museums, that is home to Pier 45.

"We traditionally don't have fires of this magnitude with warehouses," Baxter said on Saturday, adding that the pier was being evaluated for structural integrity.

"It was an impressive, massive fire."

Video footage showed huge plumes of smoke rising over the bay, creating a thick haze.

Baxter said that the fire was contained to the building and that "multiple walls on all four corners" had collapsed.

He said the building was a total loss and had housed several businesses, ferry fleet offices and multiple independent crabbers and fishers.

Pier 45 had warehouses A, B, C and D, he said, and C was the one destroyed.

Baxter said that officials did not believe anyone was inside the building but that on occasion, people who were homeless had been found sleeping inside.

Other local businesses were evacuated.

Fireboats were used to battle the blaze. Baxter said the St Francis fireboat "was aggressively protecting" the SS Jeremiah O'Brien, which was built during World War II.

The vessel, which launched on June 19, 1943, and participated in the D-Day invasion in 1944, is one of about 2,700 so called Liberty ships. The ship, a tourist attraction moored at Pier 45, had been closed because of the coronavirus pandemic.

"We are happy to say that we have really saved the Jeremiah O'Brien, and we really secured the rear end of Pier 45," Baxter said.

On the ship's Facebook page, officials, crediting the work of the firefighters, wrote, "We can confirm the O'Brien remains intact and doing well."