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King county worked with region's vehicle fleets to reduce mercury pollution

A little-known but significant source of mercury pollution is the auto tilt switch, which turns on a light when the trunk lid or hood is raised. Each switch contains more than a gram of mercury. The Clean Cars Campaign external link estimated that about 430 pounds of mercury from switches were released from end-of-life vehicles in Washington State in 2003. All studies show that removal before shredding (at the point of the auto recycler) is the most efficient strategy.

Generally, American-made cars manufactured before 2001 or foreign cars made before 1992 contain switches. American cars made after 2001 may still have mercury switches, however, model years beyond 2003 do not contain them.

Mercury from tilt switches is released into the environment when vehicles are shredded and smelted for recycling. Mercury is highly toxic and human exposure to mercury can occur from eating mercury-contaminated fish. (Mercury in water is converted by bacterial activity to methylmercury, which bioaccumulates in tissues of fish). Now, 45 states have issued fish consumption advisories related to mercury contamination, including the state of Washington external link .

To address this problem, the Local Hazardous Waste Management Program in King County (Seattle, WA) worked with 11 public and one private fleet in King County from 2004 to 2006 to remove mercury-containing vehicle switches before the vehicles were surplused. Removing the switch was a key step in reducing the amount of mercury released into the environment. The project ended in September 2006 because of a statewide Department of Ecology Automotive Mercury Switch Removal Program external link .

King County's mercury switch pilot program was covered in several local and national news releases and won national awards from the North American Hazardous Materials Management Association external link and the National Association of Counties external link

mercury switch removal
A City of Bellevue technician removes a mercury switch from a police car.
mercury switch removal
An example of a mercury pellet inside an auto tilt light switch.

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King County Solid Waste Division mission: Waste Prevention, Resource Recovery, Waste Disposal