Even though you may be specifying energy-efficient polystyrene, polyisocyanurate, and polyurethane insulation for your builds, flammability codes still require the use of flame retardant (FR) chemicals. Many of the FRs currently in use are halogenated organic chemicals, which mean they contain chlorine or bromine bonded to carbon. According to the Green Science Policy Institute, most of these FRs have not been adequately evaluated for their impact on human health and the environment. When tested, many are found to be toxic, are unable break down into safer chemicals, and/or accumulate in plants and animals.