EPA officials, who were under a federal court order to set a new standard by midnight Wednesday, said the new limit would better protect health, especially children.
"Our nation's air is cleaner today than just a generation ago, and last night I built upon this progress by signing the strongest air quality standards for lead in our nation's history," Stephen Johnson, the EPA administrator, said Thursday. "Thanks to this stronger standard, EPA will protect my children from remaining sources of airborne lead."
The new limit -- 0.15 micrograms per cubic meter -- is the first update to the lead standard since 1978, when it helped phase out leaded gasoline. It is ten times lower than the current standard, which was 1.5 micrograms per cubic meter.
The new standard announced on Thursday would require the 16,000 remaining sources of lead, including smelters, metal mines, and waste incinerators, to reduce their emissions.