Mercury has a number of unusual properties which makes it useful in a variety of applications. It is the only metal that, when in pure form, is liquid at room temperature. Mercury conducts electricity and expands evenly in response to changes to pressure or temperature. These properties have made mercury a widely used product in household, commercial, medical and industrial applications. Mercury is also one of the most poisonous natural substances known.

Despite mercury's toxicity and the availability of alternatives for almost all uses, 100 tonnes of mercury is found in Canada in thousands of products such as fluorescent lamps, thermostats, thermometers and button batteries, as well as in industrial applications. We handle mercury-containing products every day, around the house, in the workplace -- even children's toys have been found to contain mercury switches or mercury-containing batteries. An extensive list of mercury-containing products is available from Environment Canada.

Every year, over 1 million cars are recycled in Canada, containing anywhere from 675,000 to 950,000 automotive lighting switches. Each of these switches contains about 0.85 grams of mercury. Following the lead taken by import vehicle manufacturers in the mid-1990s, the North American auto manufacturing industry ceased the use of mercury switches after model year 2003. This has left behind a 10 to 15 legacy of mercury switches which need to be responsibly managed, to ensure the mercury is never released to the environment.

Canada has been working hard to decrease its mercury emissions. Between 1990 and 1995, man-made releases dropped from 32 tonnes to 11 tonnes, thanks to improvements in the base metal mining industry. By 2000, mercury releases had decreased to 8 tonnes per year.