Propylene Glycol & Glycol Ethers
Common Solvent Propylene Glycol may pose a wider range
of health effects on human health than previously
Propylene Glycol and Glycol Ethers, commonly known as PGEs,
result from the reaction of propylene oxide with a varied chain of
The PGE family of chemical compounds is based on a similarity in
molecular, structural and physicochemical properties. Clear,
viscous, colourless liquids at room temperature that have very
little odour, a slightly bittersweet taste, and low vapour
pressures amid superior solvent properties (totally miscible with
water and a great variety of organic solvents), and biodegradable
according to Lyondell .
These chemicals are manufactured as co products and are used
commercially in a large variety of industrial and commercial goods.
They are available as highly purified produce which meet
well-defined manufacturing and sales specifications.
PGEs' great degree of solvency and lower volatility makes them
valuable as coupling, coalescing, and dispersing agents; multiple
indoor sources emit PGEs, they are widely used in water-bases
paints, inks, varnishes, resins, dyes, lacquers, cleaning fluids,
agricultural chemicals and other oils and greases, pesticides. Non
solvent uses for PGEs include hydraulic and brake fluids,
anti-acing agents, PVC pipes and artificial theatrical smoke.
When produced according to specific guidelines, PGs are legally
permitted as a direct additive for processed foods and are
classified as safe. Because of their low human toxicity
(however, overexposure or spillage during handling should be
strictly avoided as a matter of good safety practice) and desirable
formulation properties they are a frequently used additive in
cosmetics, personal care products from shampoo, soaps, creams,
ointments, deodorant and toothpaste to laundry detergents and floor
wax and pharmaceutical products. PG is used in food such as
cake mixes, salad dressings, soft drinks, popcorn, food colourings,
fat-free ice cream and sour cream. It also protects food from
freezing and helps as a preservative. In food PG is listed as E
1520, in cosmetics as such in the ingredient list but for
industrial applications there is no requirement for propylene
glycol to be labelled.
Once PGEs are introduced by inhalation or oral exposure, they
are rapidly absorbed and distributed throughout the body.
Dermal absorption is to some extent slowed but subsequent
distribution is rapid. PGEs leave the body via urine and
expired air and a small portion is excreted in the faeces.
However, recent research by Harvard University and Sweden's
Kalstad University 'Common Household Chemical and the Allergy Risks
in Pre-School Age Children' has emphasized the potential of a link
between the presence of PGEs and asthma, allergies and eczema in
The researchers were looking for a combination of very specific
volatile organic compounds VOCs (8 in fact) in the home, gases that
are emitted from liquids or solids and which can damage the
environment and human health, and sought to investigate the risk
they pose in indoor air.
In the county of Varmland, Sweden the target population for the
study were 400 developing children where nearly half of the
children reported at least two symptoms of wheezing, rhinitis and
eczema in 2 separate questionnaires sent one and a half years
apart, and the other half were healthy.
Samples or air and dust were collected from the room where the
children most often slept. The results showed that concentration of
PGEs, but no other classes of VOCs, was significantly higher among
the children with rhinitis, and were twice as high as the
concentration found in rooms of the children with no symptoms.
The objective of the investigation was to study the effects of
VOCs in the home, but only PGEs in indoor air significantly
increased the risks of allergic and respiratory symptoms. Due to
the similarity of the PGEs compounds, and their overall low
concentrations, it was not possible to identify the risk of the
individual PGE compounds.
On the other hand, results of the study concluded that
PGE-outcome associations are not merely linked with frequent
cleaning, which suggests that building products are the cause of
A previous study of house painters (1989-1991) who were exposed
to water-based paints, reported significantly higher incidence of
chest tightness/wheezing, airway irritation, bronchial
hyper-responsiveness, and shortness of breath. And in a
non-occupational situation, greater chance of asthma symptoms were
observed in adults exposed to a newly painted wood or kitchen
surfaces, and/or synthetic material-based furniture.
Although the research by Harvard University and Sweden's Kalstad
University demonstrates that the bedroom concentration of PGEs are
much associated with the risks of multiple allergic symptoms,
rhinitis and eczema, and sensitisation in preschool age children, a
full extent experimental model and more testing should be carried
out to validate the results and to clarify the effects of PGEs in
ecospecifier note: "PGEs being such a broad
family of chemicals span several classifications within
ecospecifiers Cautionary Assessment Process (ES CAP). They are
normally classified in categories 1, 2 and 3 depending on the
specific chemistry. ES CAP is based on the precautionary
principle and as a result of this research, ecospecifier will
subject to standard ES CAP risk analysis, in future attach as
cautionary 'Issue of Concern' statement to all PGE compounds in
Verified Product assessments and GreenTag Certifications, where the
risks shown in these studies are 'likely to occur' or greater".
David Baggs. CEO & GreenTag
 Lyondell Chemical Company. 'Environmental Aspects Report,
Comparative Biodegradation of Propylene Glycol Ethers'. 2006.
Click here to see report.
Lyondell and Basell merge in 2007 to become LyondellBasell
Industries - visit their website for more information. www.lyondellbasell.com
 UNEP Publications. 'Propylene Glycol Ethers'. November 2003.
Click here to view publication.
 Choi H, Schmidbauer N, Sundell J, Hasselgren M, Spengler J,
et al. 'Common Household Chemicals and the Allergy Risks in
Pre-School Age Children'. Harvard University and Sweden's Kalstad
University. October 18, 2010. Click here to see full paper.
Author: Eliana Tovar-Molina
© ecospecifier 2011