Stoddard solvent

Further to my previous posting (Cons DistList Instance 19:24) about
Stoddard Solvent and other hydrocarbon solvents I can now add some
points of clarification about the hazard classification of these
substances in Europe. The news for conservators is good, I think.
Contrary to what I suggested previously, I am assured now
that--subject to some important qualifications which are explained
below--these kinds of solvents should not normally be classed as
"Toxic/Carcinogen Cat. 2/R45" according to EC conventions. This view
has been endorsed by a representative of the UK's Solvents Industry
Association.  I give apologies for any alarm I may have caused by my
first posting.  What this does highlight, however, are the
difficulties involved in how one interprets the hazard
classifications made by the EC; taken at face value, the
classifications can be very misleading, as I have found out.

The problem I had encountered was essentially to do with the way CAS
Numbers and EINECS numbers are used, under the EC's Dangerous
Substances Directive, as descriptors of the complex mixtures of
chemical substances that are petroleum distillates and most
hydrocarbon solvents.  Commonly, a supplier of a solvent will report
the CAS number in their catalogues, technical datasheets or safety
datasheets.  For any given CAS- or EINECS-numbered substance, one
can look up what hazard classification it has been assigned by the
EC and what safety labelling it requires.

This is what happened in the case of Stoddard Solvent, for example:
I simply looked up in the EC databases the hazard classification for
Stoddard Solvent using the CAS Number 8052-41-3 (which equates with
EC EINECS Number 232-489-3) that is quoted in the supplier's
catalogue.  If you do this, as I reported, they identify the
substance as Toxic, Carcinogen Category 2; health risk phrase
R45--May cause cancer.;  "Harmful" (Xn), R65.

There are two aspects to the problem: firstly, the CAS or EINECS
numbers may not precisely describe the chemical constitution of the
distillate/solvent, more the process by which it was refined; and
secondly, I have learned that there are some circumstances which
will allow a petroleum-derived product with a particular CAS or
EINECS number to be classified and labelled differently to what is
apparently stipulated for that substance.  The qualifications that I
referred to above are contained in a set of Notes (A-S) to Annex I
of EC Directive 67/548/EEC (which is the list of harmonised
classifications and labellings for substances or groups of
substances, legally binding within the EU).  Notes H, J, N and P are
especially pertinent to coal- and oil-derived substances; and Notes
J, N and P concern classification as a carcinogen.  It is probably
useful to quote these Notes in full:

   "Note J:
    The classification as a carcinogen need not apply if it can be
    shown that the substance contains less than 0.1% w/w benzene
    (Einecs No 200-753-7). This note applies only to certain complex
    coal- and oil-derived substances in Annex I.

   "Note N:
    The classification as a carcinogen need not apply if the full
    refining history is known and it can be shown that the substance
    from which it is produced is not a carcinogen. This note applies
    only to certain complex oil-derived substances in Annex I.

   "Note P:
    The classification as a carcinogen need not apply if it can be
    shown that the substance contains less than 0.1% w/w benzene
    (Einecs No 200-753-7). When the substance is classified as a
    carcinogen, Note E shall also apply. When the substance is not
    classified as a carcinogen at least the S-phrases 2-23-24-62
    shall apply.

   "This note applies only to certain complex oil-derived substances
    in Annex I."

The consequence of these Notes is that a substance like Stoddard
Solvent, or any of the other solvents I mentioned previously, which
appear superficially to be classed as "Carcinogen" may not actually
be so, if it can be shown that the substance contains less than 0.1%
w/w benzene, or if the full refining history is known and it can be
shown that the substance from which it is produced is not a
carcinogen.  So this is the explanation of how a CAS- or
EINECS-numbered solvent offered for sale can be legitimately
classified and labelled differently to the EC Annex 1 listing.
Clearly, then, the benzene content (whether it's greater than or
less than 0.1% w/w) is highly significant to the actual hazard
classification of commercial products.  Hydrocarbon solvents that
are essentially aliphatic will generally have benzene contents much
lower than 0.1% w/w. Nevertheless, it seems reasonable to expect to
be able to find out from suppliers what the benzene content of any
hydrocarbon solvent product actually is.

In short, because of these qualifications, knowing the CAS or EINECS
number does not, as I had allowed myself to assume, provide an
idiot-proof (Alan-proof!?) means of establishing the hazard
properties of complex mixtures like hydrocarbon solvents and
distillates. You live and learn, I guess.

In making enquiries about this, though, I have discovered that the
evolution (tightening) of hazard classifications for hydrocarbon
solvents in Europe has had its impact on the supply of
household/hardware grade "white spirits".  One leading UK supplier
to that market informed me that they had indeed changed their
product within the last few years in response to more stringent
hazard classification, though this seems to be more to do with
environmental hazard than with carcinogenicity.

Alan Phenix
Northumbria University, UK


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                  Conservation DistList Instance 19:25
                Distributed: Thursday, November 10, 2005
                       Message Id: cdl-19-25-001
                                  ***