[Sca-cooks] A Warning Was Cleaning Metal
t.d.decker at worldnet.att.net
Thu Sep 18 10:38:48 PDT 2008
> Was written:
>> A friend suggested putting the item in a black plastic bag, covering it
>> with ammonia, and putting it in the sun to heat up for a couple of hours.
>> Ammonia is not as toxic as oven cleaner, just don't mix it with vinegar
>> another acid. I haven't tried this myself.
> Do we have a chemist on the list?
> While I am not a chemist... please... please... under no cercumstances mix
> ammonia with chlorine bleach either. It is my understanding that the gas
> generated in the reaction of those two substances is quite toxic.
> Ammmonia + chlorine bleach equals = chlorine gas; there are some other
> nasty chemical reactions that can happen depending on the ratio of ammonia
> to bleach, and vice versa (think explosive).
> While I was working at the Trenton Times, I recall the pool building at
> Princeton University had to be evacuated once because there had been a
> cleaning incident - industrial strength bleach was used around the pools
> and somehow got into contact with some of the pool chlorine; that was a
> big oops. Luckily no one got really hurt.
> Apparently ammonia and vinegar apparently react to produce salt water.
> Ammonia being alkaline, vinegar being acid, they neutralize each other ...
> still, while this reaction was happening, I wouldn't want to breathe in
> the fumes ...
Chlorine bleach (IIRC) is usually a 5% solution of sodium hypochlorite in
pure water, not actual chlorine. Liquified chlorine is not something anyone
wants to encounter in the wild, so to speak. Liquid chlorine for pools is
usually 10-15% active chlorine. Solid chlorine for pools is about 90%
active chlorine. Mixing the two types of chlorine for swimming pools can
produce explosive reactions and release interesting levels of chlorine gas
according to a friend of mine who does maintanence at apartment complexes.
Ammonia and chlorine bleach produce chloramine gas, an unstable mixture of
nitrogen and chlorine which, in the presence of water, reduces to ammonia
and hypochlorous or hydrochloric acid. The instability makes chloramine gas
very nasty stuff to inhale.
Vinegar and chlorine bleach would tend to break down into water, oxygen, and
sodium chloride with a small amount of chlorine escaping as gas.
Irritating, unhealthy, but probably not lethal.
In general for exposure to chlorine, upper respiratory irritation begins at
about 2 ppm with greater problems occurring at 9 to 50 ppm. Bronchial
constriction may begin as low as 18 ppm with general manifestation around
200 ppm. 50% lethality between 800 and 1000 ppm. Immediate respiratory
arrest at 2000 ppm. The actual effects depend on the concentration of the
chlorine, the length of exposure, the moisture leval of the exposed tissues
and the susceptibility of the individual.
There are around 5,000-6,000 people exposed to some form of chlorine gas
each year in the U.S.. Of these exposures, about 10% show no effects while
80% show mild irritation. The other 10% show various degrees of effect with
about 1/10th of 1% being extremely effected. The statistics are open to
question, but are probably accurate enough for puposes of this discussion.
An examination of 323 incidents showed that about 21% were the result of
mixing household bleach with other chemicals.
And for your further edification, according to a research paper presented to
the American College of Sports Medicine, pool chlorination levels above .5
ppm can result in an increase in Exercise Induced Bronchocontriction. In a
study of trained swimmers after a few minutes of exercise, at .5 ppm, the
incidence rate of EIB was 20%, the same as non-pool exercise. At 1 ppm (1
to 2 ppm being common for household pools) the rate of EIB was 60%. This
may be an issue with asthmatics doing pool exercises. The caveats are this
is one research paper and to my knowledge the conclusions haven't, as yet,
been substantiated by further research.
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