Hal Faulkner (faulkner@redshift.com)
Tue, 02 Mar 1999 09:20:47 -0800
BTW,
Hydrogen sulfide, the gas that gives rotten eggs their familiar aroma, is
more toxic than hydrogen cyanide. It just smells so obnoxious that no one
in his or her right mind will hang around breathing it.
Common sense, lots of ventilation, a few MSDS's. What more does one need?
Hal Faulkner
mailto:faulkner@redshift.com
-----Original Message-----
From: Sil Horwitz [mailto:silh@iag.net]
Sent: Tuesday, March 02, 1999 7:39 AM
To: alt-photo-process-l@skyway.usask.ca
Subject: Re: question of safety or hysteria??
At 99/03/02 02:45 AM -0500, Judy wrote: (just one topic quoted)
>
>I'll add that I have made cyanide gas, not on purpose, leaving various
>toning solutions in a tray for too long. Opened the cover & got a whiff --
>no odor, but the sense of dying very soon. I made a note of the
>combination & tacked it onto the wall.
What you got a whiff of wasn't "cyanide gas" if it was odorless (actually
the
gas is hydrogen cyanide - HCN - note, just hydrogen, carbon, and nitrogen!)
as
that gas has a very characteristic almond odor. (Peach pits contain a
cyanide
compound, incidently, and are toxic if enough are ingested, which you aren't
likely to do because of the terrible taste. The peach is smart - gives you
sweet meat but inedible seed, so you throw the seed away to root somewhere
to
carry on the species.) Carbon compounds (sometimes called "organic"
compounds
because all life is made from them) are almost infinite, yet are made up of
carbon, hydrogen, oxygen, and/or nitrogen. When you mix unknown materials,
you
will get unknown results, which is why I keep repeating know what you are
using
and what happens when they react.
Now for the record, as I have stated before, except under high heat and
pressure, ferricyanides DO NOT evolve hydrogen cyanide. Furthermore, even if
they did, "cyanide" requires exposure to 150 ppm for an hour in a closed
atmosphere to endanger life; methane is more deadly. Yes, hydrogen cyanide
is
life-threatening in large amounts in a closed environment, but you are not
going to get that with ferricyanides. The latter name is very misleading.
And
if you don't smell anything (and your personal smeller is working) t'ain't
"cyanide."
Sil Horwitz, FPSA
Technical Editor, PSA Journal
silh@iag.net
Visit http://www.psa-photo.org/
Personal page: http://www.iag.net/~silh/
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