Stephen Surace, 53, of Valhalla, was taken into custody and charged with criminal possession of a weapon, reckless endangerment and unlawfully dealing fireworks.
Police shut down surrounding streets and alerted neighbors along Saldi Lane to vacate their homes while the fireworks were being removed.
The Westchester County Police Hazardous Devices Unit and the federal Bureau of Alcohol, Tobacco, Firearms and Explosives were on the scene.
Surace was taken into custody Tuesday morning after an undercover police officer purchased $1,000 worth of fireworks and observed that the basement of the home was stacked virtually floor to ceiling with several hundred boxes of fireworks, many of them used in commercial fireworks displays.
"Based on the volume of material and the potential explosive hazard, the decision was made to move immediately to arrest Mr. Surace and secure the home," Public Safety Commissioner George N. Longworth said.
Officials say some of the mortars were so large they would be considered explosives and not fireworks.
Authorities say they confiscated more than $200,000 worth of fireworks, so dangerous they require an explosives license to possess.
"I'm told by the experts, our bomb squad personnel, that there's a TNT equivalent in there," Longworth said. "If there was a detonation, the house would be leveled and damage to the surrounding areas as well."
Surace pleaded not guilty and was released on $10,000 bail.