37
Flame retardants
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
**
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
**
Mercury is sometimes found in batteries, relays and switches. Mercury
damages the nervous system and is toxic in high doses. TCO’99 requirement
states that batteries may not contain more than 25 ppm (part oer million) of
mercury. It also demands that no mercury is present in any of the electrical
or electronics components concerned with the display unit. 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.
CFCs (freons)
The relevant TCO’99 requirement states that neither CFCs nor HCFCs may be
used during the manufacture and assembly of the product. CFCs (freons) are
sometimes used for washing printed circuit boards. CFCs break down ozone
and thereby damage the ozone layer in the stratosphere, causing increased
reception on earth of ultraviolet light with e.g. increased risks of skin cancer
(malignant melanoma) as a consequence.
Lead
**
Lead can be found in picture tubes, display screens, solders and capacitors.
Lead damages the nervous system and in higher doses, causes lead poisoning.
The relevant TCO’99 requirement permits the inclusion of lead since no
replacement has yet been developed.
Environmental
requirements
* Bio-accumulative is defined as substances which accumulate within living organisms
** Lead, Cadmium and Mercury are heavy metals which are Bio-accumulative.
APPENDIX
