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(kdeghetal)
Hi there....one thing to keep in mind is that there is still a lot to be done in terms of testing when it comes to glycol ethers. They can span the gamut when dealing with toxicity....but also this should NOT be considered a binder. It falls under a category of solvents with varying ranges of volatility. So while we cannot speak to issues related to preservation (e.g. yellowing, etc.) here is some more information that follows up on Health and Safety concerns in the AIC News (Vol.8...thanks to MITRA's Health and Safety point person Kerith Koss Shrager for this):
Some Chemical Things Considered:
Glycol ethers and Glymes: Making sense of
confusing terminology
Conservators often work very closely with solvents, so it is important to be informed about their hazards and to stay up-to-date
on terminology and naming conventions, in order to recognize
which solvents may require more caution.
Glycol ethers are a large class of solvents. They may be found in
many common household products, including latex paints, paint
strippers, household cleaners and detergents, batteries, brake fluid,
printing inks, plastics, adhesives, perfumes, and cosmetics.
Glycol ethers have historically been used in the conservation
field as solvents or diluents in coatings and varnishes, adhesives
such as B-72, and solvent mixtures for cleaning. Because of
concerns about their safety, the use of glycol ethers in conservation has been reduced over the past 30 years. Glycol ether solvents
are used in the ninhydrin test for protein, and the AIC Paper
Conservation Catalog (www.conservation-wiki.com/wiki/
Paper_Conservation_Catalog) lists a glycol ether as a possible
additive in Jade 454 PVA adhesive.
Glycol ethers often do not appear on product labels, and may
be listed by a confusing variety of names, including chemical
names, trivial names, acronyms, and proprietary names. For
example, the chemical “ethylene glycol monoethyl ether”
may also be known as EEGE, Cellosolve, ethyl Cellosolve, or
2-Ethoxyethanol.
While conservators probably know glycol ethers can be
dangerous, you might not be familiar with all of the various
names by which they may be identified (see table). In particular
the name “glyme” has been used recently by the EPA: “glyme” is
a trivial name which properly refers only to glycol methyl ethers
but is confusingly used by the EPA to also refer to other glycol
ethers including diethyl and dibutyl ethers.
Of the many glycol ether solvents, only a few have been
studied in depth. Several glycol ethers have been found to cause
adverse reproductive, developmental, and other health effects.
According to the California Department of Health:
“Overexposure to glycol ethers can cause anemia...intoxication similar to the effects of alcohol, and irritation of the eyes,
nose, or skin. In laboratory animals, low-level exposure to
certain glycol ethers can cause birth defects and can damage a
male’s sperm and testicles. There is some evidence that workplace exposure can reduce human sperm counts.”
Exposure routes may include inhalation of solvent vapors and
absorption through the skin; some glycol ethers can penetrate
gloves without changing their appearance.
Recently, the EPA proposed a Significant New Use Rule
(SNUR) related to a list of 14 glycol ethers, which would allow
the EPA to evaluate and possibly prohibit the use of these
chemicals in consumer products. The EPA has found that while
potential exposure to the 14 chemicals is currently limited, there
is reason to believe their use might become more common
in products including printing inks, paints and coatings, and
batteries. The SNUR was issued because of the potential health
aic news, May 2013 9
hazards of glycol ethers:
“EPA has concerns about the 14 glymes listed in this SNUR,
all of which have similar chemical structures. EPA is concerned
about the reproductive and/or developmental toxicity of
monoglyme, diglyme, and ethylglyme and believes that individuals could suffer adverse effects from their use. In addition,
EPA has concerns about the remaining 11 glymes due to the
lack of available use, exposure, and toxicity information.”
Glymes and glycol ethers have been of concern to conservators for quite some time, and alternatives to the use of glycol
ethers in conservation have been discussed for decades, but
conservators may still use these chemicals or have older supplies in
chemical storage. In 2003, OSHA withdrew its proposed standards
on workplace exposure to 2-ethoxyethanol and 2-methoxyethanol and their acetates because there were “few, if any, remaining
opportunities for workplace exposure to these glycol ethers.” It is
important to keep in mind that conservators often use chemicals
in ways and situations that many other workers do not, and therefore government authorities such as OSHA and the EPA are less
likely to take common conservation exposures into account when
creating regulations. EPA and OSHA regulations may also be
delayed by requirements for lengthy congressional hearings.
Toxicological data on these chemicals still exists regardless of
the status of government regulation, however, and conservators
should be aware of other sources for safety information, including
the more current 2012 occupational exposure limits established
by the American Conference of Governmental Industrial
Hygienists. The ACGIH exposure limits for 2-ethoxyethanol and
2-methoxyethanol are extremely low (5.0 ppm and 0.1 ppm,
respectively, as an 8-hour time weighted average) as reflects their
high toxicity. For additional resources, see the Health and Safety
Committee Guide to Technical Resources for the Conservator
(www.conservation-wiki.com/wiki/HS_Health_and_Safety_
Technical_Resources_for_the_Conservator). Safe working
controls are definitely needed for glycol ethers, and conservators
should take care to handle these chemicals with precaution.