EPA is revising the nation's air quality standards for lead for the first time in 30 years, proposing to dramatically strengthen the standards to reflect the latest science on lead and health. The proposal recommends tightening the primary standard to protect public health by 80 to 93 percent. It would revise the existing standardof 1.5 micrograms per cubic meter of air to a level within the range of0.10 to 0.30 micrograms per cubic meter.
The agency is taking comment on alternative levels within a range from less than 0.10 to 0.50 micrograms per cubic meter. Since 1980, emissions of lead to the air have dropped nearly 98 percent nationwide, largely the result of the agency's phaseout of lead in gasoline. And average levels of lead in the air are far below the level of the 1978 standard. Lead in the air today comes from a variety of sources, including smelters, iron and steel foundries, and general aviation gasoline. About 1,300 tons of lead are emitted to the air each year, according to EPA's most recent estimates. Lead that is emitted into the air can be inhaled or, after it settles out of the air, can be ingested. Ingestion is the main route of human exposure. Once in the body, lead is rapidly absorbed into the bloodstream and can affect many organ systems.
More than 6,000 studies since 1990 have examined the effects of lead on health and the environment. Evidence from health studies indicates that lead in the blood can cause harm at much lower levels than previously understood. Exposure to lead is associated with a broad range of health effects, including harm to the central nervous system, cardiovascular system, kidneys and immune system. Children are particularly vulnerable: Exposures to low levels of lead early in life have been linked to effects on IQ, learning, memory and behavior. Lead also can cause toxic effects in plants and can impair reproduction and growth in birds, mammals and other organisms. EPA is proposing that the secondary standard, to protect the environment, be identical to the primary standard. EPA will accept public comment for 60 days after the proposal ispublished in the Federal Register. The agency will hold two publichearings on June 12, 2008: one in St. Louis and one in Baltimore. EPAmust issue a final decision on the lead standard by Sept. 15, 2008. Details about the proposal and public hearing information: http://www.epa.gov/air/lead
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