The death toll from 9/11 continues to rise 16 years later as more sick first responders lose their battles with cancer and other diseases.

Their 9/11-related sicknesses prompted the largest class-action lawsuit in New York City history, which led to the Zadroga Act.

News 12 sat down for an interview with White Plains lawyer David Worby, who was the first to predict the toxic World Trade Center dust that emergency responders were told was safe to breathe wasn’t.

In 2004, Worby filed the largest class-action lawsuit that New York City had ever seen.  It was on behalf of two, then ultimately 10,000, sick 9/11 heroes who were battling deadly cancer and who felt the city did little to protect them.

At the time, the accusation was unthinkable and doubted by respected medical and political circles.

"I think they thought it was a lawyer inventing a disease that didn't really exist," said Worby.

Worby took to Google, which was new at the time, to research Hiroshima and spills of toxins. He speculated that 9/11 workers inhaled a combination of pollutants including benzene, asbestos and PCBs that no one had ever been exposed to before. He said it somehow accelerated the latency periods for a number of deadly illnesses, but proving it would take years.

About 1,700 of Worby's clients never lived to see the $1 billion settlement, which finally came in December 2010.

Following Worby's lawsuit, the government established the Zadroga Act, which provides funding and monitors the health of roughtly 75,000 people.