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SUN-LOVERS beware: sunscreens could be toxic. A chemical commonly used in sun
lotions to protect against ultraviolet radiation kills animal cells, Norwegian
scientists have discovered. And it may become more deadly after a few hours out
in the Sun.

The widespread use of sunscreens has been increasingly questioned by experts
who say that it may not provide protection against skin cancer because it
encourages people to sunbathe for longer. Now there is evidence that a substance
called octyl methoxycinnamate (OMC), used as a UVB filter in 90 per cent of
sunscreens worldwide, may itself be toxic.

Terje Christensen, a biophysicist from the Norwegian Radiation Protection
Authority near Oslo, found that half of the mouse cells in an ethyl alcohol
solution died when OMC was added at five parts per million, a much lower
concentration than occurs in sunscreens. Over 90 per cent of the cells survived
in the solution without OMC.

When the team shone a lamp on mouse cells in the OMC solution for two hours,
to simulate midday sunshine, even more died than in the original OMC solution.
Christensen suggests this is because the products of reactions between OMC and
light are roughly twice as toxic as OMC itself.

Christensen believes OMC could damage human cells if it penetrates the outer
layer of dead skin. Some sunscreens do this so they should be treated 鈥渨ith
caution鈥�, he says. 鈥淭hey should only be used when other protective measures
肠补苍苍辞迟.鈥�

Rona MacKie, a dermatologist from the University of Glasgow, stresses the
difficulties of extrapolating from animal cells to people. But she agrees that
sunscreens should only be used as a last line of defence against UV
radiation.

The Cosmetic Toiletry & Perfumery Association, which represents sunscreen
manufacturers in Britain, points out that OMC 鈥渉as been thoroughly tested for
safety鈥� and approved by regulatory authorities in Europe and the US.