Re: Oxalate fumes
Richard Sullivan (richsul@roadrunner.com)
Sun, 04 May 1997 15:11:40 -0600
>Date: Sun, 04 May 1997 13:14:32 -0400
>From: Sil Horwitz <silh@iag.net>
>Subject: Re: Palladium BWK, warmer tones
>X-Sender: silh@mail.iag.net
>To: John Rudiak <wizard@laplaza.org>
>Cc: alt-photo-process-l@skyway.usask.ca
>Comments: "alt-photo-process mailing list"
>
>At 10:40 AM 970504 -0600, you wrote:
>
>>David, I would be very careful about the fumes containing oxalates. Are
>>you wearing a respirator?
>
>Oxalic acid and oxalates decompose in the dry state, forming carbon
>dioxide, carbon monoxide (toxic), formic acid, and water. I can find no
>record that decomposition occurs in weak aqueous solutions. The oxalates
>themselves are quite toxic, but decompose on heating to the above
>compounds. A simple respirator would be of no value at all, but a good
>exhaust system would be of help to get rid of the carbon monoxide - but
>that's only with the dry chemical.
>
>Anyone have experience with this? Personally, dust (including that from
>ordinary chemicals) is more of a problem to me than fumes.
>
>
>Sil Horwitz, FPSA
>Technical Editor, PSA Journal
>silh@iag.net
Sil
I supposed I'd be dead by now if this were the case. Throw a spoonful of
oxalate on a hot plate and it'll sputter and mostly evaporate (depending on
the oxalate.) I've gotten zapped by the fumes on occasion and this explains
it, it's the formic acid! I doubt that you'd get enough carbon monoxide
this way to do any real harm, but the formic acid can be a real sting in
the lungs. I've never had a problem with hot developer giving off fumes,
and as you say that's not in the chemistry.
Dick
Bostick & Sullivan
PO Box 16639, Santa Fe
NM 87506
505-474-0890 FAX 505-474-2857