Cadmium is a silver-white, soft, malleable, toxic, metallic element. Although it is widely distributed in trace amounts throughout the natural environment, the metal is infrequently found in high concentrations.
An almost unique combination of properties renders cadmium useful in a wide variety of consumer and industrial products, but, in contrast to chlorinated solvents and formaldehyde, the normal use of cadmium-containing products by consumers is rarely a source of exposure. Emissions and wastes from smelting operations and production processes and from the disposal of final products containing refined cadmium all contribute to increased concentrations of cadmium in air, water, and soil.
Because the quantities of cadmium embodied in many products are so small, cadmium recovery from these products is impractical. Among the major uses of refined cadmium, only nickel-cadmium batteries contain a sufficient proportion of cadmium to make recovery feasible. The cadmium from few batteries is recovered at present, however; instead, the batteries end up in landfills or as incinerator ash. Among other incidental contributors of cadmium to the environment are agricultural fertilizers, in which cadmium is a common associate of phosphates; dusts from cement manufacture; and emissions from coal and oil combustion.
Among the various sources of exposure to cadmium, the disposal of final products containing refined cadmium appears to be the best candidate for incentive-based approaches to control. One reason is that there are broad third-party effects associated with disposal, arising because consumers receive inadequate signals about the social costs associated with disposal. Another reason is that the variety of cadmium-containing products and the varying degrees to which suitable substitutes are available could make typical command-and-control regulatory approaches complex and costly. Accordingly, this