The requirement of The RoHS Directive is to ensure that any new electronic equipment or product after the 1st of July 2006 contains not more than 0.01% by weight per homogeneous material of cadmium, and not more than 0.1% by weight per homogeneous material of lead, mercury, hexavalent chromium, polybrominated biphenyls or polybrominated diphenyl ethers.
A homogeneous material is defined by the RoHS directive as any individual material such as a plastic or ceramic or metal, an example would be an insulated wire containing two homogeneous materials, the PVC insulation on insulated copper wire. Any component of a product may contain several different homogeneous materials.
Each homogeneous material within each individual part of the product must comply with the RoHS Directive the housings, cabling, printed circuit boards, components, fixtures and fittings. To detect the restricted substances, one must know which materials are permitted in a given application and which are not, and also where to look for them, since they are sometimes found deep within the sample to be tested.
If you are an assembler of OEM or CEM Printed Circuit Boards, a European manufacturer selling within the EU, or an importer of manufactured electronic products into the EU, you must be able to demonstrate compliance with the restrictions on hazardous substances.
To ensure compliance an enforcement authority may ask to see evidence that a producer has used due diligence and taken reasonable steps to comply with the requirements of the RoHS Directive. Failure to comply could result in the eventual withdrawal of your product from the market.
Producers must be able to demonstrate compliance by submitting technical documentation or other information to the enforcement authority on request and retain such documentation for four years after the electronic equipment is placed on the market.