Howard Street Tunnel fire
The Howard Street Tunnel fire (also known as the Baltimore Freight Rail Crash) began on July 18, 2001, in a railroad tunnel under Howard Street in Baltimore, Maryland. The derailment of a 60-car CSX Transportation freight train in the through-route Howard Street Tunnel sparked a chemical fire that raged for five or six days.
Source: Wikipedia — Howard Street Tunnel fire (CC BY-SA 4.0)