In New Zealand in the 1930s, farmers reportedly had trouble with exploding trousers as a result of attempts to control ragwort, an agricultural weed.
The history was written up by James Watson of Massey University in a widely reported article, "The Significance of Mr. Richard Buckley's Exploding Trousers"[3] − which later won him an Ig Nobel Prize.
Experimenters tested four substances on 100% cotton overalls: Each of these were put to four different ignition methods: flame, radiant heat, friction, and impact.
Although not naming "the herbicide" as sodium chlorate, they confirmed that trousers impregnated therewith would indeed vigorously combust upon exposure to flame, radiant heat, and impact, though their friction tests did not cause ignition.
However, combustion (i.e. an exothermic chemical reaction between a fuel and an oxidant) is not the same as an explosion, which involves a rapid increase in volume accompanied by the release of energy in an extreme manner (i.e. a shock wave).