At 3:07 p.m. on Wednesday, July 18, 2001, a CSX Transportation train derailed in the Howard Street Tunnel under the streets of Baltimore, Maryland. Complicating the scenario was the subsequent rupture in a 40-inch water main that ran directly above the tunnel. The flooding hampered extinguishing efforts, collapsed several city streets, knocked out electricity to about 1,200 Baltimore Gas and Electric customers, and flooded nearby buildings. The crash interrupted a major line associated with the Internet and an MCI WorldCom fiber optic telephone cable.

Throughout the incident, fire officials were plagued with three problems: fighting the fires in the tunnel; the presence of hazardous materials; and the weakening structural integrity of the tunnel and immediate surrounding areas.

Though the original cause of the fire is unknown, at the time of this report, fire officials believed that the derailment ruptured a tanker car carrying a flammable liquid chemical that fueled the fire. The fire response quickly jumped to five alarms within the first two hours of the incident. Thick black smoke emanated from both ends of the tunnel and seeped through manhole covers along Howard Street and other nearby streets.

Firefighters first attempted to fight the fire by entering the tunnel from either end, using vehicles with special rail wheels, but they were forced back by intense heat and a lack of visibility. They then initiated an alternative plan. Firefighters lowered large diameter hose from the street above into the tunnel where attack lines were set up for suppression operations. Firefighters were finally able to reach the burning cars at about 10:00 p.m.

The initial attack significantly lowered the temperature of the burning cars within a few hours.

At the height of the incident, 150 firefighters were on the scene working to extinguish the fire. For the first time since they were installed in 1952, civil defense sirens were activated at 5:45 p.m. to warn citizens of impending danger from the fire and hazardous materials. On the night of the derailment, city officials closed down entrances to the city from all major highways. Baseball games between the Baltimore Orioles and the Texas Rangers at nearby Camden Yards were postponed that night and the following night because of the hovering cloud of black smoke from the tunnel fire.