<P> In the United States, the U.S. Environmental Protection Agency estimated that if all 270 million CFLs sold in 2007 were sent to landfill sites, around 0.13 metric tons of mercury would be released, 0.1% of all U.S. emissions of mercury (around 104 metric tons that year). The graph assumes that CFLs last an average of 8,000 hours regardless of manufacturer and premature breakage . In areas where coal is not used to produce energy, the emissions would be less for both types of bulb . </P> <P> Special handling instructions for breakage are not printed on the packaging of household CFL bulbs in many countries . The amount of mercury released by one bulb can temporarily exceed U.S. federal guidelines for chronic exposure . Chronic, however, implies exposure for a significant time, and it remains unclear what the health risks are from short - term exposure to low levels of elemental mercury . Despite following EPA best - practice clean - up guidelines on broken CFLs, researchers were unable to remove mercury from carpet, and agitation of the carpet--such as by young children playing--created localized concentrations as high as 0.025 mg / m in air close to the carpet, even weeks after the initial breakage . </P> <P> The U.S. Environmental Protection Agency (EPA) has published best practices for cleanup of broken CFLs, as well as ways to avoid breakage, on its web site . It recommends airing out the room and carefully disposing of broken pieces in a jar . A Maine Department of Environmental Protection (DEP) study of 2008 comparing clean - up methods warns that using plastic bags to store broken CFL bulbs is dangerous because vapors well above safe levels continue to leak from the bags . The EPA and the Maine DEP recommend a sealed glass jar as the best repository for a broken bulb . </P> <P> Health and environmental concerns about mercury have prompted many jurisdictions to require spent lamps to be properly disposed of or recycled, rather than being included in the general waste stream sent to landfills . Safe disposal requires storing the bulbs unbroken until they can be processed . </P>

How is the light in a compact fluorescent light bulb produced