Department of
Environmental Quality

Mercury is a naturally occurring element present throughout the environment. When released into the air as a result of human activity, it can become an air toxic.

In the U.S., coal-fired power plants are the primary source of mercury emissions to the air. In March 2011, EPA proposed new Mercury and Air Toxics Standards, which would require many power plants to install pollution control technologies to reduce emissions of mercury, arsenic, chromium, nickel, and acid gases. Facilities would have up to four years to meet the standards. Once fully implemented, the standards would prevent 91 percent of mercury in coal from being released into the air.

DEQ is the state agency delegated responsibility for administering the federal Clean Air Act in Idaho. This responsibility includes issuing permits that limit the volume of hazardous air pollutants, including mercury, that facilities may emit and conducting inspections of these facilities to assure compliance with federal and state air quality standards. In 2011, Idaho adopted a new rule that applies to facilities that are not subject to a federal national emission standard for hazardous air pollutants and have mercury air emissions that exceed certain levels. These facilities will be required to implement Best Available Control Technology (BACT) for their mercury emissions.

Household Sources of Mercury Emissions

Common household sources of mercury emissions include broken or discarded thermometers and compact fluorescent light bulbs (CFLs). Because CFLs use less electricity than regular light bulbs, they actually reduce the overall amount of mercury in the environment. When disposed of properly, CFLs offer even more benefit to the environment because the mercury is properly contained and reclaimed rather than discarded in a manner that can cause contamination. Overall CFLs are safe to use, but should be handled carefully and recycled when spent.