Restriction of Hazardous Substances (RoHS) EU Directive has prohibited the use of 10 poisonous substances in electrical and electronic equipment. These substances are:
- Cadmium (Cd) (0.01% maximum)
- Lead (Pb) (0.1% maximum)
- Mercury (Hg) (0.1% maximum)
- Hexavalent chromium (Chromium 6) (0.1% maximum)
- Polybrominated Biphenyl (PBB) (0.1% maximum)
- Polybrominated Diphenyl ether (PBDE) (0.1% maximum)
- Bis(2-Ethylhexyl) Phthalate (DEHP) (0.1% maximum)
- Butyl Benzyl Phthalate (BBP) (0.1% maximum)
- Dibutyl phthalate (DBP) (0.1% maximum)
- Di-isobutyl phthalate (DIBP) (0.1% maximum)
Cadmium is restricted to 100 parts per million (0.01%) whereas the rest of the substances are limited to 1000 parts per million (0.1%). The above-mentioned maxim concentration of substances applies to each homogeneous material that the product is composed of. A homogeneous material is a material with uniform composition and cannot be separated mechanically into different parts.
The RoHS directive also referred to as lead-free directive was initiated to restrict the pollution of the environment by toxic electronic and electrical waste. The disposal of the products containing the above-mentioned elements even in small traces is harmful to the plants and animals present in the ecosystem. They pollute the surroundings and are also dangerous in terms of occupational exposure. RoHS is closely associated with the Waste Electronic Equipment Directive (WEEE). While RoHS controls the utilization of hazardous chemicals in electrical and electronic equipment, the WEEE monitors the disposal of these products. Nowadays in the PCB industry, even the laminates meet the ROHS compliance.