Re: Xylene Substitute

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To:Jeff Silverman <>
Date:Thu, 20 May 1999 05:48:20 -0400
Content-Type:text/plain; charset=us-ascii

Concerning the statements on Limonene:

1. The GRAS (generally regarded as safe) status mentioned in the
email - this is from the FDA (Federal Drug Administration), not OSHA.

The FDA regulates drugs and food additives. Limonene has been
approved by the FDA for use in very small amounts as a food 
additive to give the food an orange-y, citrus-y smell and flavor.
Limonene is therefore GRAS when used in such small quantities 
when used as a food additive (a few drops in a large batch of
candy for example).

The FDA does NOT regulate, extend or state that Limonene is GRAS 
when used in large quantities or in ways other than as a 
food additive. In other words, the FDA does not extend this GRAS 
status to using gallon(s) of it in a histology lab. 

OSHA does not extend a GRAS statement to any chemical. It states
what a chemical will and won't do in terms of hazards.

Therefore, no federal agency states that Limonene is GRAS for
anyone working with it in a laboratory. Chemical hygiene and
safety procedures still apply. Read the MSDS for additional

2. Not all communities will allow the dumping of Limonene down
the drain. It is oily and floats. Check with your area's water
and sewer treatment plant. You may still need to have it hauled
away, like xylene.

Hope this helps.


Peggy A. Wenk, HTL(ASCP)
William Beaumont Hospital
Royal Oak, MI 48073

Jeff Silverman wrote:
> Jorge,
> I use any of the d-limonene products: Americlear from Allegience Health
> care, Hemo De from Fisher, or Clearene from Surgipath. D- limonene is a
> food grade oil, a terpene extracted from the peels of oranges and
> grapefruits. It is non toxic but it has a strong orange smell- many people
> like it and many others hate it. Some people have an allergic sensitivity
> reaction to it but no one in my lab has been bothered in ten years. Not
> only is it non-toxic and "generally regarded as safe" by OSHA, d-limonene
> has anticancer activity and is being fed to human cancer patients in
> clinical trials. We can dump it down the sink and use it in all staining
> stations of paraffin and Pap smears. We also use it to purge the tissue
> processor- one change lasts me ten purges (two weeks) but  the purge
> solution can go in the garbage not down the sink because it is too
> saturated with paraffin. I still use xylene  in my VIP for processing
> because d-limonene is not as good, some blocks are greasy. But this exposes
> us to xylene only every five or six weeks when we change the processor.
> D-limonene has a high vapor pressure and coverslipping multiple slides is
> easy, no "corn flake nuclei" from rapid evaporation. Also, you need to keep
> a jar of xylene at the coverslipping  bench to clean smeared slides since
> the -d-limonene does not dissolve the Cytoseal medium.  I heartily endorse
> it but watch out for allergies. E mail if you need more info.
> Jeff Silverman
> Southampton Hospital
> ----------
> > From: Jorge Villalona <>
> > To:
> > Subject: Xylene Substitute
> > Date: Wednesday, May 19, 1999 7:23 PM
> >
> > Hi, everyone in the field of histotechnology.
> >
> > Our histology lab is looking for a xylene substitute that is easy to
> > dispose of, great for diparaffinization, dihydration, coverslipping and
> > most important; nonhazardous to our health.
> > If anyone is using a xylene substitute, please give us your input.
> > We greatly appreciate your commends and recomendation.
> >
> > Thanks.
> > Jorge Villalona; HT (ASCP)
> >

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