An investigation into the causes of laundry fires - spontaneous combustion of residual fatty acids

Several laundry fires have been investigated during the period from 1993 to 1999, where the cause is thought to be spontaneous combustion. In each case cotton materials such as kitchen towels, serving towels and sports kit have been washed, placed directly into tumble dryers and subjected to heating. Combustion has occurred amongst these materials when the cloth is heaped or stacked immediately after drying. These materials are subject to contamination through their use with various unsaturated fatty acids. This work investigated the residence of selected fatty acids on cotton materials during various normal washing cycles. It was shown that significant measurable levels of linoleic and oleic acids were recoverable from material even after very hot washing cycles (90°C). If such materials were then exposed to heating (during the tumble-drying process) such that their auto oxidation temperatures could be reached and if subsequent heat was not allowed to dissipate then it is conceivable that spontaneous combustion could occur.