Nowadays, the production and use of phosgene in the factories have been very severely restricted worldwide. There are aSabic Innovative Plastics (formerly GE Plastics), Bayer, and Asahi/Chi Mei have independently developed and are using non-phosgene processes. They all take the same overall approach where polymerization relies on the transesterification of diphenyl carbonate (DPC) with bisphenol A. This is more commonly termed as the melt process which has the advantage of making a product undiluted form that may be pelletized directly. Disadvantages include the need for equipment to withstand high temperatures and high vacuum. With lower plant construction costs and lower feedstock costs, it is anticipated that this kind of non-phosgene process will be widely adopted for PC production throughout the world.