Lead is a metal found naturally in the environment and in manufactured products. Historically, major sources of lead emissions into the air have been motor vehicles and industrial sources. As a result of the phasing out of leaded gasoline and the introduction of other state and national regulations, airborne lead concentrations have decreased significantly. Industrial processes are now the major source of airborne lead emissions; these sources include utilities, lead smelters, waste incinerators and manufacturers of lead-acid batteries.


Missouri has a long history of lead mining and processing. Historical lead mining areas include the old lead belt around Park Hills in St. Francois County and the tri-state lead area around Joplin in Jasper and Newton counties. Lead continues to be mined from the new lead belt, or Viburnum trend, in Iron and Reynolds counties. Herculaneum, located in Jefferson County, was the site of the nation’s last primary lead smelter, which discontinued primary lead smelting in 2014. Secondary lead smelting, in which lead is recycled from lead-acid batteries and other sources, continues to be done at Buick in Iron County and at Forest City in Holt County. 

Health Affects of Lead

People can inhale airborne lead directly, and they can also ingest it after it settles onto surfaces or soils. Once in the body, lead is rapidly absorbed into the bloodstream, and it accumulates in bones. Lead exposure is associated with several health effects that have an adverse impact on kidneys, the cardiovascular system, the central nervous system, and the immune system. Children are more susceptible to the damaging effects of airborne lead than adults because they breathe in more air per minute, typically spend more time outdoors, and exhibit greater hand-to-mouth activity than adults. Children are also more vulnerable to the health effects of lead because their minds and bodies are developing rapidly.

Air Quality Standards and Monitoring

The primary National Ambient Air Quality Standards (NAAQS), based on health effects, for lead is a concentration of 0.15 microgram of lead per cubic meter of air (µg/m3) averaged over three months. The standard is not met if the three-month rolling average concentration exceeds that level once or more within a three-year period. 

Missouri monitors lead concentrations in the air at several locations across the state. Lead is monitored at five additional ambient locations and five locations within facility fence lines by industrial facilities. Monitoring at these industrial facilities follows procedures reviewed by the state, and results are reported to EPA and to the public. Click on the Monitoring tab to learn more about these air monitoring sites. Click on the Data tab to learn more about the data collected from this sites.

More information is available on EPA's Lead webpage.



The primary and secondary ambient air standards for lead have remained at 0.15 micrograms per cubic meter since 2008. The primary standard reflects EPA's concern for public health while the second standard demonstrates concern for public welfare. EPA bases the standard on the highest rolling three-month average over a period of three years and two months. A monitoring site meets the standard when this rolling three-month average is less than or equal to 0.15 μg/m3.

Departmental information about lead

  • Health effects
  • Missouri's lead legacy
  • 2008 standard and pertinent documents


Lead Monitoring Network