In 2000, Swedish construction giant Skanska introduced a minimum standard for chemicals use, identifying five substances - CFCs, halon, acrylamide, asbestos and PBCs - which may not be used during construction at any Skanska site. A number of Skanska's business units have supplemented the global list with their own list of substances that may not be used in their markets. The Swedish construction sector is also launching a new system, with which Skanska has agreed, to phase out the use of particularly hazardous chemical substances from chemical products and building products.