The three sheriff's deputies had been driving on the highway at the time of the crash, followed the smoking taxi, and ran to pull the victims from the burning wreckage.
The deputies, Zalady Ralleta, Robert Rood and Christopher Sheriff, were treated for minor burns and smoke inhalation and are all "doing very well," according to the sheriff's office.
Investigators with the California Highway Patrol are still looking into the cause of the crash. The 49-year-old cab driver, who was able to escape from the fiery vehicle, was not arrested.
The victims were two tourists visiting from Cincinnati, Ohio. Karen Marshall, 59, and her husband Dennis, 61, hailed a DeSoto Cab Co. taxi after landing at San Francisco International Airport.
They were on their way to downtown San Francisco on Interstate Highway 280 when the taxi driver smelled smoke north of Candlestick Park, CHP spokesman Shawn Chase said Tuesday.
Although the driver decided to pull off at the Mariposa Street exit, about two miles down the road, the vehicle's brakes failed while navigating the turn. The vehicle, moving at 40 mph, crashed into a highway support pillar and burst into flames, Chase said.
Both of the passengers were pronounced dead at San Francisco General Hospital.