Preamble : Readers should be aware that the abbreviation PFCs is
being used for two different classes of classes of products.
PFCs (perfluorocarbons), covered by the Kyoto Protocol, are
organofluorine compounds that contain exclusively carbon and
fluorine. Examples are CF4 (tetrafluoroethane) and C2F6
(hexafluoroethane or perfluoroethane). These substances have
high global warming potential but do not bioaccumulate and are
considered to be of low order of toxicity. They are gases or
volatile liquids. While other compounds which contain atoms
other than carbon and fluorine are also sometimes called PFCs,
they should in effect be considered specifically as fluorocarbon
derivatives. Examples are PFOA (perfluorooctanoic acid:
C8HF15O2) and PFOS (perfluorooctanesulfonic acid : C8HF17O3S ).
These are typically surfactants with long carbon chains, with
uses in fluoropolymer preparations and for water repellancy. The
properties of these substances - bioaccumulation and stability -
means that voluntary and regulatory