Glycol ethers belong to a very common group of chemical substances known as volatile organic compounds (VOCs). This group of substances includes more than 80 derivatives used in a wide range of everyday products and solvents due to their specific amphipathic physico-chemical properties (i.e. containing both hydrophilic and hydrophobic residues). Examples of VOCs include benzene, styrene, and toluene. Some of them are found in products such as water-based paints, wooden floor varnishes, cleaning products, hair dyes, cosmetic products, etc. About 30 of these substances are currently used in industrial applications. Occasional and long-term exposure to certain VOCs may pose a risk to human health.
Glycol ethers can be divided into two chemical subtypes: the ethylene series (e.g. ethylene glycol butyl ether or EGBE, diethylene glycol butyl ether or DEGBE), and the propylene series (e.g. propylene glycol monomethyl ether or PGME).
The Agency’s role
The Agency received a formal request in October 2003 from the Directorate General for Health and the Directorate for economic studies and environmental evaluation to implement certain provisions in the inter-ministerial action plan regarding glycol ethers, over a period of several years.
Within this framework, the Agency was tasked with:
- evaluating public exposure to glycol ethers by measuring:
- the most common glycol ethers in indoor air;
- glycol ether emissions during application of paint in realistic conditions;
- documenting release of glycol ether vapours from building materials and furnishings;
- determining the current status of scientific knowledge on glycol ethers: analysis of the actions taken following the recommendations of the collective expert appraisal carried out by the French National Institute of Health and Medical Research (Inserm) in 1999, study of new toxicological findings published since this appraisal, and drafting of an overview concerning exposure of the population to glycol ethers by all routes.
The Agency was also called on in 2004 and 2005 to respond to other requests concerning glycol ethers, particularly those made by the Directorate General for Labour, in order to:
- broaden ongoing research activities to include the occupational population;
- review current substitutes for glycol ethers;
- issue an opinion on the health relevance of the 0.5% threshold for the beta isomer of PGME in currently-marketed products. This impurity is classified as a category 2 reprotoxic substance and its concentration must therefore not exceed 0.5%.
Involvement in the government’s action plan and inclusion of the occupational population
- in order to evaluate exposure of the public to glycol ethers (measurement of the most common glycol ethers in indoor air and measurement of emissions during application of paint) and to collect data on release of glycol ether vapours from building materials and furnishings, the Agency assigned research projects and studies to some of its partners including, the French Scientific and Technical Centre for Building (CSTB), the French Environment and Energy Management Agency (ADEME), Inserm and university groups.
On the basis of the data collected, the Agency requested that its Expert Committees examine possible new recommendations in view of the summary on exposure of the general and occupational populations to glycol ethers.
A summary of the data was compiled based on the literature and the results of studies carried out since 2004. The corresponding report, "Glycol ethers: overview of knowledge on exposure of the general and occupational populations in France", was published in September 2008, along with the Agency’s Opinion. In this Opinion, ANSES recommended that specific studies be carried out on the reprotoxicity of propylene glycol ethyl ether (PGEE)and of the beta isomer of PGEE to improve knowledge on population exposure to various glycol ethers and to limit exposure for some of these compounds, particularly GEs classified as reprotoxic, both for the general and occupational populations;
- indoor air: A research product conducted by the CSTB on indoor air measurement of four very common glycol ethers (EGBE, EGBEA, 2PG1ME and 2PG1MEA) was financed by ANSES and ADEME and carried out in the framework of the programme organised by the French Indoor Air Quality Observatory (OQAI) between October 2003 and December 2005. The results were published in December 2006. Moreover, as part of Action item 14 of the French National Environment and Health Action Plan (PNSE) 2004-2008, the activities of the OQAI were reinforced and extended, and thereby provided data on more varied indoor environments (homes, public spaces, schools, and offices);
- paints: ANSES and the CSTB also conducted joint studies on emissions of GEs from paint and decorating materials. For one of the studies, the Agency requested that CSTB characterise glycol ether emissions during application of paint in a residential room. The study was carried out by CSTB in three phases:
- a test in an emission chamber, with characterisation of the main VOCs up to 28 days (laboratory approach);
- an experiment in a test room in the MARIA model house for innovative air research (MARIA project; see insert “Did you know”), with determination of the main VOCs up to 28 days (in situ approach);
- simplified modelling of changes in glycol ether concentrations to study the impact of air renewal rates.
The study characterised the type of glycol ethers emitted during application of paint and determined changes in their concentrations over time. This new knowledge on emission levels from paint was provided to the Agency and included in the expert appraisal report.
- construction materials: Furthermore, studies intended to better understand release of glycol ether vapours from building and decorating materials fall within the scope of other projects on VOCs coordinated by ANSES. The Agency was provided with results of studies on the concentrations of DEGBE, EGBE, and 2PG1MEreleased from materials such as PVC coatings, tile and wall adhesives, particle board, etc. in order to evaluate population exposure to GEs. Based on this data, the Agency published a Qualification procedure for VOC emissions from building and decorating materials indicating corresponding concentration limits related to release of several glycol ethers in indoor environments;
- toxicological data and collective expert appraisal: An update of the collective expert appraisal published in 1999 by Inserm was launched at the request of AFSSET in autumn 2004. The group of scientists mandated by Inserm to update this collective expert appraisal analysed new available information up to 2005 on the toxicity of conventional or new glycol ethers. On the basis of this analysis, a new expert appraisal was published by Inserm in June 2006. The results were submitted to the Expert Committee (CES) on assessment of the risks related to chemical substances which was consulted on 6 July and 29 September 2006 concerning recommendations for additional research. The CES issued its conclusions on 1 December 2006 and the Agency published an Opinion on research recommendations concerning the toxicity of glycol ethers in July 2007. Furthermore, the Agency proposed reference values for certain GEs in 2010:
- a toxicity reference value based on reprotoxic effects for ethylene glycol ethyl ether (EGEE)
- occupational exposure limits (OELs) in workplace air for ethylene glycol butyl ether (EGBE) and its acetate (EGBEA)
Substitution of glycol ethers
The Agency called on the company RPA to review the various ways of substituting glycol ethers in the occupational environment. The results were provided to the Agency in May 2007 and were included in the final ANSES opinion concerning glycol ethers.
Health relevance of the threshold for the beta isomer of PGME in products
The Agency appointed its CES on assessment of the risks related to chemical substances to address this question. A rapporteur was nominated in May 2006 to carry out a health risk assessment specifically on the beta isomer of PGME (1PG2ME and 1PG2MEA) in accordance with the procedure then in force at the European level as per Regulation 793/93/EEC. The results of this expert appraisal were published in August 2007. The proposed risk assessment was carried out on the basis of maximum authorised PGME concentrations in products, and not on the basis of exposure data representative of the French market. The methodological difficulties encountered led the Agency to recommend additional studies, specifically to establish a clearer assessment of consumer exposure to 1PG2ME and 1PG2MEA.
Overview of population exposure to glycol ethers
A working group reporting to the CES on assessment of the risks related to chemical substances was tasked with producing an overview on population exposure to glycol ethers. It included experts from the CES on assessment of the risks related to chemical substances and from the CES on assessment of the risks related to air environments. The working group’s activities were supported by projects and studies carried out by ANSES partners between 2004 and 2007 including the National institute for industrial environment and risks (INERIS), the Poison control and monitoring centres (CAP-TV), CSTB, French Health Products Safety Agency (AFSSAPS), National Research and Safety Institute (INRS), etc.
On the basis of all the data published on GEs between 2004 and 2007, and examination of the current recommendations, the Agency issued its opinion on glycol ethers in September 2008.