Another Major Source of Mercury Pollution: Light Switches in Scrapped Cars

The least known major source of mercury pollution in the United States may be releases from scrapped automobiles. Until recently, automakers used mercury in several components, including switches that turn on a light when car owners open a hood or trunk. (The liquid mercury flows when the hood or trunk is opened, and completes an electrical connection to illuminate the light.) Historically, automakers used approximately 12 tons of mercury per year in car switches. Although ball bearings can replace mercury in convenience lighting, automakers did not stop using mercury in these components until 2002.

Mercury escapes into the air from automobile switches when older cars are crushed and melted down, and the amount of mercury in car switches is substantial. A recent study by the state of Michigan, the Alliance of Automobile Manufacturers and others found that nearly half the cars in the state contained a switch holding approximately 0.8 grams of mercury apiece. The Clean Car Campaign, a coalition of groups that has championed the cause of getting mercury out of automobiles, reported in 2001 that an estimated 200 tons of mercury was contained in cars then in use. (Click here for details.) Tons of this mercury will spew into the air out of iron and steel plant stacks over the next 10 or so years, when these cars are junked and recycled into new steel.

Michigan found that removing the switches takes one to two minutes per car on average without extensive expertise or training. But despite the fact that scrap yards routinely remove components in vehicles and drain fluids and oil to reduce pollution, they do not remove mercury switches, partly because they are not compensated for taking them out.

In some states auto light switches are the largest source of mercury pollution. A federal pollution database, the Toxic Release Inventory (TRI), and a recent report from the state of New Jersey found that iron and steel foundries are the single largest mercury emitter in the state of New Jersey, at about 1,000 pounds per year. Coal-fired power plants in the state came in second, emitting about 700 pounds annually.

Mercury is a Major Public Health Threat

Car switches may each contain less than a gram of mercury, but it takes very little to cause harm. Like lead, mercury damages the brain and nervous system. Mercury exposure can lead to learning disabilities, attention deficit disorders and mental retardation. The effects of prenatal and infant mercury exposure include the inability to recall and process information, and impaired visual and fine motor skills. Mercury exposure also can affect an adult's nervous system, causing nerve cell death and scarring in select areas of the brain.

Children at early stages of development are at most risk, according to the Centers for Disease Control and Prevention, the Environmental Protection Agency, and most international science agencies. Based on recent estimates, approximately one in six women of childbearing age in the United States may have mercury in their blood above the level that would pose a risk to a developing fetus. Thus, some 630,000 newborns may be threatened every year by neurological impairment from exposure in-utero. Infants and children also are endangered because their developing brains are extremely sensitive to mercury, which they can ingest from breast milk and contaminated fish. Meanwhile, elevated mercury levels in adults can adversely affect male fertility and blood pressure, and may contribute to heart disease.

Americans are primarily exposed to mercury by eating certain fish. Industrial facilities emit the chemical into the environment, and a particularly dangerous form of it -- methylmercury -- accumulates in the tissue of large predator fish, such as shark, swordfish and tuna.

Mercury pollution has contaminated approximately 12 million acres of lakes, estuaries and wetlands -- 30 percent of the national total -- and more than 473,000 miles of streams, rivers and coastlines. In 2002, 44 states issued warnings about eating mercury-contaminated fish, a 63 percent jump from 1993, when 27 states issued such warnings. Nineteen states have issued statewide advisories for mercury in freshwater lakes and rivers, and 10 states have issued advisories for canned tuna.

Federal Policy Too Weak to Protect Public

There are several factors that underscore the need for prompt action to address this problem: mercury's threat to public health, the significant contribution that mercury switches make to nationwide pollution, and the fact that the window of opportunity to remove the mercury from cars manufactured before 2002 is limited. If the government fails to require switches to be removed from cars before they are recycled, it will miss an opportunity to prevent tons of mercury pollution, because as the auto fleet is modernized, a smaller and smaller percentage of cars will contain mercury switches over the next 10 years.

Unfortunately, EPA, the federal agency responsible for protecting the public from hazardous air pollutants such as mercury, has failed to address the vast majority of mercury pollution caused by switches in automobiles, and only has long-term plans to do so. Last year, only after NRDC demanded that EPA take action, did the agency insist that such plants institute a materials acquisition program specifying that scrap suppliers remove mercury light switches from trunks and hoods. These foundries also must inspect incoming scrap to ensure that switches are removed.

However, EPA's rule only applies to the large facilities that process about 10 percent of the automobile scrap each year. The remaining 90 percent winds up in so-called "mini-mills." EPA is only now beginning to consider establishing mercury removal requirements for them. The agency's delay means that more and more mercury is released daily from cars that are recycled with their switches intact, notwithstanding the fact that the Clean Air Act required EPA to issue stringent regulations by November 2000 for sources that account for 90 percent of mercury pollution nationwide.

EPA's laxness has prompted some states to take steps to curb mercury switch pollution locally. Maine, for example, recently passed a law requiring automobile scrap yards to remove convenience lights, and automakers to pay the scrap yards as partial compensation for removing the switches and delivering them for safe disposal. NRDC, working with several health and environmental groups in Maine, helped the state defend its law against a suit brought by automakers, and the court upheld the landmark provision. (For more information, click here.) Other states are considering similar legislation. But without federal standards to address this problem nationwide, mercury switches will be covered by a patchwork of state requirements.