Despite the tremendous advantages offered by the PCBs to the engineering industry, a significant quantity toxic waste with the potential of polluting the environment is released as a inevitable byproduct. The PCBs are made with various materials to forge them into require structure with custom parameters. Since all of the material used in PCBs undergoes various processing before being used in PCB the level of pollution gets increased.
For example let us consider the epoxy board which is made from glass fibers or plastic sheets merged together with industrial grade epoxy adhesives. In order to merger them each sheet is treated using various concentrated chemicals to get rid of the residues the excess solution is cleansed with another chemical solutions to make it PCB friendly this entire process release various chemical which is toxic to the environment. Even the raw material used in making the epoxy boards under chemical process so it is a chain of toxic chemical processes from earthed minerals to functional PCB. Not to mention the flux used to bond the solder paste which usually contains 30+ chemical and petroleum products which emits toxic gases oily residues when heated. Filtration and containment techniques are used to arrest these effects but they are not perfect such that significant quantity is released anyways.
IPC standards enlist the allowable amount of chemical to be discarded into the environment. A quality board must have almost no post manufacturing emission and residues that may harm the user. Due to the impact of pollution heavy metals like lead are prohibited to use in almost every electronic products to minimize the toxic effect. New and improved methods that can ease the manufacturing process and cause less pollution to the environment are continuously evolving every day. Recycling can also reduce the pollution.