The manufacture of shoes is an important industry in Mexico—particularly in the Guanajuato region which produces each year around 244 million pairs of shoes in over 7,000 enterprises that employ 135,000 people directly (and some 270,000 indirectly). Most of these shoes are fit with microcellular polyurethane shoesoles many of which, in turn, are blown with HCFC-141b. Other than rigid insulation foams, the blowing agent requires blowing capability only—while providing good structural properties—no thermal insulation.