These Regulations implement EU Directive 2002/95 which bans the placing on the EU market of new electrical and electronic equipment containing more than agreed levels of lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyl (PBB) and polybrominated diphenyl ether (PBDE) flame retardants.

In short & sweet to reduce the harmful substance in devices

It could stand for the Restriction of the use of certain Hazardous Substances Directive. This directive came into force on the 1st July 2006. From this date, producers of eight categories of electrical and electronic equipment were not able to place on the market products that contain six "banned" substances unless specific exemptions apply. These six substances are: Lead, Mercury, Hexavalent chromium, Cadmium, Polybrominated biphenyl flame retardants and Polybrominated diphenyl ether flame retardants.

PBDE is not one chemical, but a group chemicals called polybrominated dibenzyl ethers. They are one of a group called brominated fire retardants (BFR) commonly used in the manufacture of plastics and rubbers to make them fire proof. They are becoming controversial because they may be toxic, particularly to children.

One thing to look out for in foam mattresses is the use of PBDE's. These are flame retardants used to compensate the fact the foam is highly flammable.

PBDE's have been banned in Europe and are about to be banned in California.

This is because PBDE's or PolyBrominated Diphenyl Ethers have been found in humans. These particles are like the PCB's that were banned a few decades ago. They have been found to accumulate in humans (and animals) and not break down.

This has lead to concerns they might be carcinogenic. A pretty safe bet in avoiding PBDE's is buying organic or natural latex mattresses. Wool is also a natural flame retardant as so does not require PBDE's.

Methylene diphenyl diisocyanate, often abbreviated as MDI, is known as an aromatic diisocyanate.