The RoHS EU directive that came into affect in July 2006 banned 6 substances from being used in electrical and eletronic equipment. However, since then, others have come on board with their own version of the directive. Look at China for instance.  Although China bans the same materials, they do it in a different way and in some areas they are more strict on what is required for compliance. See http://www.rohscompliancedefinition.com/china-rohs.html California also has laws that prohibit 4 of these substances since January 2007. These being:

• Cadmium
• Hexavalent Chromium
• Lead
• Mercury

These directives to nee to be regularly checked to insure that any changes to these are adhered to. This is particularly important if your product currently falls under an exemption as the requirements may change. It is also important for each company selling into these markets to make a statement on what is considered due diligence. That way, its employees know what is expected of them and what the ramifications are for not following the required process. A good description can be found here: http://www.rohscompliancedefinition.com/due-diligence-rohs.html