Bales of cotton were classified by the International Maritime Organization (IMO) code regulations as a flammable solid (Class 4.1), which required hazardous goods papers to accompany waterborne shipments. Various scientific investigations were conducted to evaluate the flammability hazard of bales of cotton to determine if this hazardous designation was valid. Cigarette (NFPA 261/ ASTM E1352), match (NFPA 705) and open flame (CA TB 129) tests were conducted; the potential for self-heating and spontaneous combustion was evaluated; and the potential of cotton bales sustaining smouldering combustion in their interiors at various compression densities was studied. These studies showed that bales of cotton should not be required to have the hazardous designation, 'flammable solid', and led to the IMO and the US Department of Transportation (DOT) removing the designation for baled cotton [compressed to a density of 360kg/m3(22.4lb/ft3) or greater; meets ISO 8115], with effect from 1 January 1999.
