In an industrial waste treatment centre, a “pit” fire alarm was activated at 7:45 am after detecting the outbreak of fire in pit no. 4 containing organic solids. Simultaneously, the automatic foam gun extinguisher was activated in pits nos. 3 and 4. The security services of a neighbouring company observed black smoke emanating from the pits and alerted the emergency services.

Fire-fighters arrived at 8:07 am and activated the anti-intrusion barriers; it was only at this point that the remote surveillance company responded by sending a guard. Fire-fighters extinguished the fire using a foam layer and then observed that the sprinkler system had activated in a second zone with no trace of fire in this instance.

The day before, drums contaminated with isocyanates had been rinsed in the cleaning bay, and the backwash sludge had been emptied into pit no. 4. A slow exothermic reaction, due to the presence of residual isocyanates, was the cause of the organic solid content in the ignited pit.

Technicians were reminded of the waste sorting instructions for dealing with significant amounts of reactive product contained in contaminated packaging.