A federal appeals court has ruled negligence was not the cause of a third World Trade Center Tower collapse on 9/11.

The court ruled a company owned by developer Larry Silverstein and others can't be held liable. Utility company ConEdison claimed the fuel from diesel backup generators that tenants were allowed to install burned for hours, leading to the collapse.

World Trade Center Tower 7 crumbled several hours after the Twin Towers were destroyed. Nearly 500 Long Island residents were among almost 3,000 people killed in the terrorist attacks on Sep. 11, 2001.