Another chemical exposure issue in the news at times involves mercury. Some people are concerned about the mercury present in silver amalgam dental fillings. First a little background: mercury is a metal that is liquid at room temperature. Until recent years almost all thermometers had mercury in them, as well as many types of switches. Today, most mercury exposure originates with the burning of coal. When the coal is burned thousands of tons of mercury are released annually from the smoke stacks and pushed into the air. This mercury comes back down to earth and becomes part of the food chain, especially with fish. When the mercury becomes part of the food chain it is changed from being a simple metal to what is known as organic mercury or methyl mercury. We cannot digest the plain metal mercury, but the organic mercury is toxic to us. Dental silver amalgam creates a new metal with silver and mercury and does NOT have organic mercury. To be continued.