Since the opening of the Holland Tunnel in November 1927, a number of minor fires had occurred within the tunnel, all of which were handled without incident. In the spring of 1949, an unusual fire underscored the potential hazards that exist in the day-to-day transport of hazardous materials through the tunnel. The fire started around 8:30 a.m. when a drum of carbon disulfide fell off a trailer truck on Friday, May 13 about a third of the way into the tunnel. The highly flammable chemical leaked out onto the hot surfaces of the truck. In 1949, trucks were required to display decals to signify the transportation of dangerous cargo. This tractor-trailer entered the tunnel without decals, and police were completely unaware of the potentially hazardous chemicals moving through the tunnel. Had they known, the fire might never have occurred as the truck would have been redirected to one of the bridges instead.