A firefighter was injured and a historic building destroyed in a two-alarm fire near the San Francisco Zoo Saturday afternoon, according to fire officials.

The fire in the Fleishhacker Pool building, located next to the zoo parking lot, was reported around 1 p.m.

The building, once part of a massive swimming pool complex on the site, has sat empty and derelict for decades. It was heavily involved in smoke and flames when firefighters arrived on the scene and Assistant Chief Tom Siragusa said the decision was quickly made to attack the blaze from outside and avoid the risk to firefighters. 

"We may have been inside for less than 30 seconds," Siragusa said.

One firefighter was injured by heat and smoke as she was exiting the building, but has since been examined and returned to duty, Siragusa said.

The building's roof collapsed, and Siragusa said it was "totally destroyed."

The fire's cause remains under investigation but is viewed as suspicious in nature, Siragusa said.

Long abandoned and boarded up, the building is known to attract the homeless.

A total of 23 companies and 80 personnel responded to the fire, and some units will remain on scene tonight checking for remaining hot spots. The zoo closed early today at 2 p.m. in response to the fire, largely due to parking and logistical issues. No visitors, employees or animals were injured, however, and the zoo will reopen tomorrow, officials said in an online statement. 

There were no current or future plans to use the Fleishhacker building, according to Connie Chan, a spokeswoman for San Francisco's Department of Rec and Park.