Flame retardant materials are often extremely harmful to human health. Despite this, they are found in many types of synthetic materials which would otherwise ignite quickly. Researchers from EMPA in Switzerland have now succeeded in producing non-harmful flame retardants. Synthetic materials made from organic polymers usually burn very well due to their high carbon content. When in the form of foams, they ignite even more easily, and, depending on their chemical compositions, they produce toxic gases such as hydrogen cyanide or carbon monoxide. For this reason, polyurethane foams and other similar products have to be treated with flame retardants. These foam materials are widely used as insulation and packaging materials and as expanding spray foams. Conventional halogenated flame retardants such as tri(chloropropyl) phosphate (TCPP) or some polybrominated diphenyl ethers (PBDE) are suspected of being harmful to health and the environment. The new flame retardant materials are organic phosphorus-containing compounds, called phosphoramidates. The researchers synthesized several of these substances, which differ from each other in terms of the type of amine substituents attached to the phosphorus, and added them to the polyurethane foam in increasing concentrations.