The Restriction of Hazardous Substances Directive (RoHS) became European Law in February 2003. Together with the Waste Electrical and Electronic Equipment Directive (WEEE) which is setting collection, recycling and recovery targets for all types of electrical goods it is part of a legislative initiative to solve the problem of huge amounts of toxic e-waste.
Apart from in exempted industries (such as medical), the following 6 substances are those being controlled:
All these are limited to 1000 parts per million except for Cadmium at 100 ppm.
The ppm limits apply to each and every homogeneous material within an item. Thus a radio comprises a case, screws, washers, a circuit board, speakers etc. A circuit board comprises a bare PCB, ICs, resistors, switches etc. A switch comprises a case, a lever, a spring, contacts, pins etc. The contact perhaps comprises a copper strip with a surface coating.
Everything that can be identified as a different material must meet the limit. So if it turns out that the switch's contact coating was gold with 2300 ppm Cadmium then the entire radio would fail the requirements of the directive.
Definition and links courtesy of: