Restriction of Hazardous Substances (RoHS) is a European Union (EU) directive aimed at reducing the amount of hazardous substances used in electronic systems. It covers several types of materials and lead is a common concern. RoHS compliance is generally required to sell products in EU countries.
The RoHS directive restricts the maximum amount of various materials permissible in any mechanically separable component of an applicable product. Relevant materials include:
Hexavalent chromium (Cr6+)
Polybrominated biphenyls (PBB)
Polybrominated diphenyl ether (PBDE)
Bis(2-ethylhexyl) phthalate (DEHP)
Butyl benzyl phthalate (BBP)
Dibutyl phthalate (DBP)
Diisobutyl phthalate (DIBP)
In cases where no RoHS-compatible alternative exists to serve a required role, products may be listed as "RoHS by exemption". Such exemptions are intended to be phased out over time as new materials are found.
The lead restriction applies particularly to leaded solder, leading to the increased adoption of lead-free solder.
Lead and cadmium restrictions have substantial impact on batteries. Lead-acid batteries are often listed as compliant by exemption.
Hexavalent chromium restrictions impact zinc-plated screws and other hardware.