Re: DAB disposal

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From:"Karen D. Larison" <> (by way of histonet)
To:histonet <>
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I have copied a note on DAB disposal that appeared on the listserve some
months back from Anatech:

Date:          Wed, 29 Apr 1998 16:05:08 -0400
From:          "Anatech Ltd." <>
Subject:       DAB disposal

Let's clear the air about DAB.  It's method of manufacture does not alter
its mutagenicity.  It is a documented mutagen.  In fact, the entire
benzidine family of dyes has such a solid record of mutagenicity that the
National Toxicology Program has issued a rather strong update (January
1988).  All such dyes tested on rodents were found to be positive.  In two
independent in-house reviews, NTP voted to list the entire family as KNOWN
HUMAN CARCINOGENS.  An NTP outside peer review subsequently recommended the
group be listed the same way.  Once finalized, these decisions will, if
left unchanged, require U.S. laboratories to treat benzidine compounds as
carcinogens under OSHA's Hazard Communication Standard.  This means extra
labeling, additional protective measures and special consideration in the
Chemical Hygiene Plan (under OSHA's Laboratory Standard).

While it is easy to handle DAB safely now that stable solutions and pellets
are available, adherence to compliance issues is not to be taken lightly.

With tighter scrutiny from OSHA, the EPA (and state hazardous waste
agencies) will become even more interested in the subject of disposal than
they already are.

Chlorine bleach is NOT effective in removing the mutagenic properties of
DAB.  While it possibly may break the molecule down (reaction products are
unidentified), introduction of chlorine into the end products simply
produces another mutagenic chemical.  This has been verified by Lunn &
Sansone.  Using chlorine bleach is neither chemically sensible nor
effective. Fortunately, most if not all suppliers of DAB have eliminated
this procedure of detoxification from package inserts and MSDS's.

There are two recommended methods of treatment.  The most commonly used one
currently involves potassium permanganate and sulfuric acid.  End products
are known to be non-mutagenic.  The second uses horseradish peroxidase to
form a solid which is readily isolated.  The fluid remaining is
non-mutagenic, but the precipitate retains its mutagenicity.  The only
purpose in performing this method is to reduce the volume of hazardous

With any commercially available device purporting to detoxify hazardous
chemicals, it is imperative that the user have documentation from the
manufacturer that all reaction products have been properly tested and found
to be non-hazardous.  It is possible that some devices detoxify the liquid
and filter out a hazardous solid.  If so, the filter must be handled as a
hazardous waste.

For further information, see:

NTP, 1998.  National Toxicology Program Update (January 1998), Attachment
2.  Available on-line at

Lunn & Sansone, 1990.  Destruction of hazardous chemicals in the
laboratory.  Wiley & Sons (pages 35-41)

Lunn & Sansone, 1991.  The safe disposal of diaminobenzidine.  Appl. Occup.
Environ. Hyg. 6:49-53.

Dapson & Dapson, 1995.  Hazardous materials in the histopathology
laboratory:  regulations, risks, handling and disposal.  ANATECH LTD.,
Battle Creek, MI. (pages 25-27, 109-111 and 162-163)

1020 Harts Lake Rd.
Battle Creek, MI 49015

Date:          Tue, 22 Dec 1998 18:49:40 -0500 (EST)
Subject:       DAB disposal

Dear Histonetters,
	I thought bleach did nothing to breakdown DAB.  Isn't there a potassium
permanganate solution you can use?  Please let me know if anybody has the
recipe.  Thanks and Merry Christmas to all!.............Cindi

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