RoHS
RoHS, also known as Lead-Free, stands for Restriction of Hazardous Substances. RoHS, also known as Directive 2002/95/EC, originated in the European Union and restricts the use of six hazardous materials found in electrical and electronic products in which include Lead (Pb), Cadmium (Cd), Mercury (Hg), Hexavalent Chromium (Hex-Cr), Polybrominated Biphenyls (PBB), Polybrominated Diphenyl Ethers (PBDE).
http://www.rohsguide.com