Until a few years ago, the factory used to manufacture half a million thermometers annually. However, production is reported to have fallen owing to declining demand in Western markets where environmental and public health concerns over mercury have led to the replacement of products such as mercury thermometers with non-mercury thermometers. Although probably best known as the silver liquid in thermometers, mercury has over 3,000 industrial uses. Mercury and its compounds are widely distributed in the environment as a result of both natural and man-made activities. The utility, and the toxicity, of mercury have been known for centuries.
Mercury occurs naturally in the environment as mercuric sulfide, also known as cinnabar.
Cinnabar has been refined for its mercury content since the 15th or 16th century B.C. Mercury is present in numerous chemical forms. Elemental mercury itself is toxic and cannot be broken down into less hazardous compounds. In 1973, U.S. consumption of mercury was 1900 metric tons. It is used primarily in battery manufacturing and chlorine-alkali production as well as in paints and industrial instruments. Not only are methylated mercury compounds toxic, but they can accumulate in the environment and food chain.