Flame retardants are present in printed circuit boards, cables, wires,
casings and housings. Their purpose is to prevent, or at least to delay
the spread of fire. Up to 30% of the plastic in a computer casing can
consist of flame retardant substances. Most flame retardants contain
bromine or chloride, and those flame retardants are chemically related
to another group of environmental toxins, PCBs. Both the flame
retardants containing bromine or chloride and the PCBs are suspected
of giving rise to severe health effects, including reproductive damage in
fish-eating birds and mammals, due to the bio-accumulative* processes.
Flame retardants have been found in human blood and researchers fear
that disturbances in foetus development may occur.
The relevant TCO'99 demand requires that plastic components
weighing more than 25 grams must not contain flame retardants with
organically bound bromine or chlorine. Flame retardants are allowed in
the printed circuit boards since no substitutes are available.
Cadmium is present in rechargeable batteries and in the colour-
generating layers of certain computer displays. Cadmium damages
the nervous system and is toxic in high doses. The relevant TCO'99
requirement states that batteries, the colour-generating layers of
display screens and the electrical or electronics components must not
contain any cadmium.
Mercury is sometimes found in batteries, relays and switches. It
damages the nervous system and is toxic in high doses. The relevant
TCO'99 requirement states that batteries may not contain any
mercury. It also demands that mercury is not present in any of the
electrical or electronics components associated with the labelled unit.
There is however one exception. Mercury is, for the time being,
permitted in the back light system of flat panel monitors as there
today is no commercially available alternative. TCO aims on
removing this exception when a mercury free alternative is available.