On Fri, 25 Feb 2005 09:25:25 +0000, Cuprager wrote:


All points taken, but *I* would neither recommend breaking asb board
apart to have a look for the fibers or do it myself... i dont see the
point in putting yourself at that kind of risk.

What kind of risk? The risk associated with occasional exposure is
so small it is almost impossible to define - crossing a road is far
more dangerous.

My local authority charges £25 to
sample... not a lot of money considering the potential hazard.

Hazard is the potential to cause harm. Risk is a measure of the
likelihood of a specified harmful effect in specified circumstances.
It is important to distinguish between hazard and risk. Asbestos is a
classic example of how hazard alone does not make a risk.

Although there is no safe level for exposure to asbestos the lowest
level which people have been known to develop health problems from
asbestos is 1f/ml over an exposure period of 20 years.

The background level in towns of asbestos fibres is about 0.000003 to
0.0003 fibres per milliliter (f/ml) of air. In buildings the
background level is about 0.000007 to 0.006 f/ml. One fibre _can_
kill - but it almost never does, we all breath several fibres each
and every day.

The Ontario Royal Commission on Asbestos assumed a building exposure
level of 0.001 f/ml and calculated this gave a risk (over 10 years)
of about 20:1,000,000, about 1/50th of the death risk of driving 10
miles a day to work. The UK DOE calculated a lifetime risk of about
1:100,000 or 1/100th of the risk to non smokers of passive exposure
to others cigarette smoke.

If you chose not to take the small risk of collecting a sample that
is your choice - but in terms of risk to your family going for a 2
mile car drive is much more dangerous.




--
Peter Parry.
http://www.wpp.ltd.uk/