The Concrete Was On Fire

Following up a link to "In the pipeline", an industrial chemist's blog (don't ask), I found some interesting information about ClF3, a particularly nasty compound which "sets sand on fire". In a
safety notice about the compound, a manufacturer, Air Products, says:

... a major incident involving ClF3 occurred the first time a one-ton steel container was loaded with liquid ClF3 for bulk shipment. However, ... the steel container wall ... split, ... instantaneously releasing 907 kg of cold ClF3 liquid onto the building floor. The ClF3 dissolved the 30 cm thick concrete floor and another 90 cm of gravel underneath the spill. The fumes that were generated (chlorine trifluoride, hydrogen fluoride, chlorine, hydrogen chloride, etc.) severely corroded everything that was exposed. One eyewitness described the incident by stating, “The concrete was on fire!”

Still, it can't have been that bad if there was an eyewitness left alive to tell the tale.