>
> Sandy King wrote:
> <It is hard to understand why you would use chrome alum instead of
> formaldehyde for *safety* reasons. My understanding is that chrome
> alum is a much more dangerous chemical than formaldehyde. I use
> both -- just wanted to let you know that chrome alum should be used
> with great care.>
>
> Although it is good to claim that all chemicals should be used with
great care,
> in this case we shouldn't compare apples and oranges. Chrome alum is by
far less
> toxic than formaldehyde, which has the skull and crossbones symbol (T)
on the
> bottle. Chrome alum has no danger symbol at all. But the chemists among
us
> should know better...
>
> Klaus Pollmeier
Klaus is no doubt correct, but even he overlooks the most obvious and
relevant difference between the two materials which is of course their
volatility.
Chrome alum can be handled with perfect safety simply by avoiding contact
with skin. If you have to put your hands in it you just wear gloves.
Safe handling of formaldehyde requires a fume cupboard (or breathing
apparatus) although many of us will have simply relied on good ventilation
we are still exposing ourselves to possibly hazardous levels.
Peter Marshall
petermarshall@cix.compulink.co.uk