Some 20 to 50 million metric tonnes of e‐waste are generated worldwide every year, comprising more than 5% of all municipal solid waste. When the millions of computers purchased around the world every year become obsolete they leave behind lead, cadmium, mercury and other hazardous wastes. In the US alone, some 14 to 20 million PCs are thrown out every year. In the EU the volume of e‐waste is expected to increase by 3 to 5 per cent a year. Developing countries are expected to triple their output of e‐waste by 2015

CRTs have relatively high concentration of lead and phosphors (not phosphorus), both of which are necessary for the display. The United States Environmental Protection Agency (EPA) includes discarded CRT monitors in its category of "hazardous household waste".