Mercury is a naturally occurring element that can be found in air, water and soil. Pure mercury is a liquid metal that has traditionally been used to make thermometers, light bulbs and switches. Mercury can be exposed to humans when coal is burned (mercury is in coal), when hazardous wastes are burned, when chlorine is produced, when mercury products are broken, when it is spilled and when mercury in the air settles in water and builds up in food supplies such as fish and shellfish.

The danger of being exposed to mercury is that it can harm the brain, heart, kidneys, lungs, immune system and nervous system.

To learn more, go to:

http://www.epa.gov/hg/about.htm