Stanley Forman's news photos have gripped Boston for decades. Now 80 years old, Forman still listens to three police scanners in his truck, hustling for the next big photo. 

But the image he'll always remember is one he took of a fatal 1975 fire. 

As the fire was racing through an apartment building, Forman saw a firefighter who had just reached a young woman and a 2-year-old girl trapped on a rickety fifth-story fire escape. Then, the unthinkable happened.

"And then it went. Just collapsed. For whatever reason, it collapsed. The fire escape collapsed," Forman told CBS News. "They're falling. There's no doubt they're falling, and the fire escape coming down behind them. I realized two people had fallen to the ground."

Forman said it left him shaking.

"I just watched something awful, awful happen," he said. "I never had doubts about getting the picture, but I just watched something awful happen."

Forman said it still gets to him 50 years later. "I watched death in front of me," he said.

A firefighter, Robert O'Neill, dangled with one arm clutching the fire engine's ladder and survived. But the fall killed 19-year-old Diana Bryant. Tiare Jones, Bryant's 2-year-old goddaughter, landed on top of Bryant and lived.

Forman's haunting photo of the fall, published worldwide, earned him the Pulitzer Prize for Spot News Photography, his first of three Pulitzers.

It also woke up the city of Boston.

"This is what can happen when fire escapes are neglected and they need to be used during an emergency," Warren Kinder, director of the National Fire Escape Association, told CBS News. He said back in 1975, there were no regulations for inspections.

Within months of the fire and Forman's photo being published, Boston changed the city code to require fire escapes to be certified as safe every five years. 

Kinder said the impact of Forman's photo is "undeniable, and had a ripple effect throughout the country."

Forman said, "I think it scared people. And it also made them aware. How's my fire escape?"