LETHAL R-134a concentrations from evaporator failure

Don Saunders don-saunders at tanstaaflgroup.com
Sun Nov 23 08:57:14 EST 1997

E. William Lawrence III wrote:

> 4000 ppm of just about anything will kill something for sure, except
> maybe oxygen or nitrogen!

A little research might help your argument.  One of the major
manufacturers of CFC 12 used an animal test as part of their
manhufacturing specs.  100% of the test animals had to survive 24 hours
in an atmosphere of 20% oxygen and 80% CFC - i.e., the nitrogen was
replaced by CFC.

On the issue of whether or not 134a can be lethal to passengers:
	How likely is a total release in a short period with no introduction of
outside air?
	Anyone truly concerned that this might happen in their car has the
choice of eliminating the danger by having their AC system evacuated.
	Cars are lethal in many ways.  Anyone who gets in one should recognize
that they are one of the leading causes of death in the US.  Potential
leakage of refrigerant from the AC unit should be the least of their

Let's keep in mind that RISK is a combination of HAZARD (toxicity) and
EXPOSURE.  Without both, there is no risk.

A note to the anti-chemical crowd:  The most toxic chemical known to
mankind is a natural product, has the potential to be present on your
dinner plate especially if you eat only 'organic' food, and kills very
few people in the US each year (my guess is less than 10).


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