Plastics play a major role in building. Next to packaging, the construction industry is the second biggest consumer of plastics, representing 22 percent of plastic resin sales. The positive contribution of plastics cannot be denied: they offer relatively durable low-maintenance products; their light weight reduces shipping energy; foamed plastics are typically the insulations with the highest R-value; plastic caulks, foams, and housewraps are crucial in sealing buildings; plastic resins are used in engineered wood; and plastic wood helps displace old-growth and arsenic-treated wood. But they have their down-sides, negatives on the environmental scorecard. the first plastics were plant-based, with Celluloid first patented in 1870. The first synthetic polymerBakelitewas invented in 1907, however, and over the next 40 years, plastics became ever more associated with the oil economy, inextricably connected with a corporatization of economic life (Fenichell, 1996). They became, in Geisers (2001. p. 45) words, the flagship material of the postwar Consumer economy, structured by the suburb and the automobile. Their light weight was geared to extend production and consumption loops, and their inexpensiveness hid other environmental costs not registered by the market. These include the productionintentional or otherwiseof some of the most toxic materials ever seen. Many of these chemicals have been dangerous for workers to produce, and impossible to isolate completely from the community and environment throughout their life-cycles. To name just a few: vinyl chloride monomer and benzene are known carcinogens. Styrene is a suspected carcinogen; the plasticizers, especially phthalates, are likely both carcinogenic and hormone-disrupting; formaldehyde is a suspected carcinogen. And foamed insulations are the source of ozone-depleting HCFCs.