CFL's contain a very small amount of mercury in the tubing which is about 5 milligrams. This is reported to cover the tip of a ball point pen. A regular thermometer contains about 500 milligrams which means it would take about 100 broken CFL light bulbs to equal the older thermometer.
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Also, If every American home replaced just one light bulb with an ENERGY STAR qualified bulb, we would save enough energy to light over 3 million homes for a year, more than $600 million in yearly energy costs, and prevent greenhouse gases equivalent to the emissions of over 800,000 cars.