Debra Sarno, 54, killed, after her disabled taxi is rear-ended by a tractor-trailer, after which both caught fire, on the I-93 Zakim Bridge near Malden.

State Police confirmed one person was killed in a fiery crash on the Zakim Bridge Monday morning.

Officials said that a Malden taxi cab stopped in the right travel lane going northbound before it was struck from the back by a tractor trailer. State Police said it appeared that the taxi cab had broken down.

Firefighters rushed to help, but the fire proved too intense. By the time the vehicles were towed away, neither were recognizable. Both burned down to the metal.

The taxi driver, Debra Sarno, 54, of Chelsea was pronounced dead at the scene.

Sarno worked for Malden Taxi. The cab company said Sarno was waiting for a tow truck with her hazards on. She was too afraid to wait outside of her car because she was on the bridge.

Employees said they are heartbroken over the loss of Sarno.

Her neighbors couldn't believe what happened.

"I was quite shocked to hear, especially given the nature of the accident...She was a nice gal," a neighbor of Sarno's said.

The operator of the tractor trailer was transported to Mass. General Hospital with minor injuries.

The accident shut down all northbound lanes of Interstate 93 and caused a huge traffic tie-up in Boston.

The crash involved a car and a tractor-trailer sent flames and black smoke into the sky during the Monday morning commute.

One southbound lane and the ramp from the Sumner Tunnel to the bridge were also shut down.

The cause of the crash is still under investigation. No charges have been filed.