Dick,

An excellent note.  Just because a chemical is not very carcinogenic
does not mean that it could not cause damage to cells (i.e.: our
bodies).  An important point to remember about ANY fixative is that one
of its' primary functions is to KILL the cells as well as preserve them
in as life like a state as possible.  Constant dermal and inhalation
exposure to formaldehyde will cause major sensitization problems (in
certainly has with me).

It might also be important to note that the unpolymerized monomer
solutions of GMA and MMA are potent sensitizes, if I'm in a room with an
open bottle I develop a rash within 24 hours.  

As an aside I remember the days of no ventilation in the histology
labs., or at best there was a window fan (in those lab.s that had
windows.  You could smell the histo-lab a corridor away.  It would be
criminal to go back to those days.

ANATECH wrote:
> 
-snip-
> 
> The great hazard of formaldehyde is not its proven carcinogenicity.  Anyone
> interested in formaldehyde's effects on humans should read the preamble to
> OSHA's Formaldehyde Standard (Federal Register 52(233):46168-46312;
> December 4, 1987).  According to studies cited therein, formaldehyde has
> been directly implicated in causing tumors in the lungs, naso- and
> oro-pharynx and nasal passages of humans occupationally exposed to levels
> of formaldehyde not unlike conditions existing in histology laboratories a
> few decades ago.  Repeated and prolonged exposure increases the risk.
> True, the risk is small, and with the improved ventilation in most US labs
> (at least), one could justify ignoring the issue altogether.  I personally
> do not care to increase my risk, but the significance is truly minor.
> 
> However, Formaldehyde presents a vastly greater risk to histotechnologists
> by being a potent sensitizer.  Once sensitized, you will probably
> experience worsening symptoms for the rest of your life even if you leave
> the field.  You cannot get away from formaldehyde.  It off-gasses from most
> building products except untreated lumber.  It has been widely used in the
> permanent press treatment for fabrics (although glyoxal is replacing it
> there as it is in histological fixatives).  It comes out of carpeting
> drapes and upholstery.  You will get more colds, suffer with them longer,
> may develop asthma, or experience worsening asthmatic attacks.  OSHA
> reported in 1982 that 79% of the histotechnologists studied showed
> respiratory and dermatological symptoms consistent with
> formaldehyde-induced sensitization, a 2-fold increase over the control
> group.  Exposure levels for those histotechs were 0.2-1.9 ppm, levels that
> were really rather moderate for the time (pre-1987).
> 
> The Formaldehyde Standard was written in great part because of the
> unacceptable conditions in pathology labs.  Industry had long since cleaned
> up its act.  The standard's preamble specifically singles out pathology
> labs as being among the worst for workplace exposure.
> 
> Perhaps many of you do not remember or were not in the field before 1980.
> A few techs were concerned about chemical exposures, but were mostly
> stymied by glib administrators and uncaring co-workers whose attitudes were
> strikingly like those being aired on the HistoNet today.  NSH struggled
> many years to bring these concerns to light, organizing a Health & Safety
> Committee, sponsoring studies of formaldehyde and xylene exposure,
> providing workshops and lectures on all aspects of health and safety, and
> compiling lists of resource materials and personnel.  The real leaders of
> this field have taken the subject very seriously.  Please don't go back
> down that road in reverse; if you do, do it alone.
> 
> I want to set the record straight.  Formaldehyde can be worked with safely.
> No histotech should ever need a respirator.  Simple, properly designed
> ventilation can easily keep vapor levels below the OSHA Action level of 0.5
> ppm averaged over 8 hours.  If you stay below that level (and the STEL of 2
> ppm over 15 minutes), you avoid almost all of the standard's requirements
> and have a safe workplace at least for the inhalation of formaldehyde
> vapors.
> 
> Skin contact with formaldehyde is another issue altogether.  Latex surgical
> gloves offer NO protection (breakthrough time is seconds to a few minutes).
> Very thin nitrile gloves are probably marginally better, but breakthrough
> times are not available.  This form of exposure is the cause of most
> modern-day sensitization reactions to formaldehyde.  Butyl and nitrile
> gloves comparable in thickness to dishwashing gloves will protect you for
> most histological tasks involving formaldehyde (Schope et al., 1987,
> Guidelines for the selection of chemical protective clothing, ACGIH,
> Cincinnati, OH).  Unfortunately, grossing is difficult with these
> protective devices.
-unsnip-

> 
> I could continue with another tiresome page on xylene, but I'll spare you.
> 
> Dick
> 
> ANATECH LTD.
> 1020 Harts Lake Rd.
> Battle Creek, MI 49015
> 616-964-6450
> 800-262-8324
> E-mail: anatechnet-link.net
> http://www.net-link.net/anatech

-- 
best regards,
Bob
Robert Schoonhoven
Laboratory of Molecular Carcinogenesis and Mutagenesis
Dept. of Environmental Sciences and Engineering
University of North Carolina
CB#7400
Chapel Hill, NC 27599
Phone 
office 919-966-6343
   Lab 919-966-6140
   Fax 919-966-6123 

Don't go around saying the world owes you a living; the world owes you
nothing; it was here first. 
Mark Twain [Samuel Langhornne Clemens] (1835-1910)