MDI/TDI isocyanates, Wanhua, BASF, Covestro

MDI and TDI are the building blocks of polyurethanes: building insulation foams, seats, soles, adhesives. Their synthesis runs through phosgene, a lethal gas that rules out any improvised plant and locks the sector: five groups hold nearly 90% of world MDI. Wanhua, from nothing, has become the leading producer and is doubling its capacity in Fujian, an industrial shift towards China on a link once European and American.