Image: Glyme molecule
Glyme is a nickname for 1,2-dimethoxyethane, a solvent chemical in the glycol ether family. Glyme, and its close cousins diglyme, and ethylglyme, are suspected reproductive toxins. For example, monoglyme is officially required to carry the warnings "May impair fertility" and "May cause harm to the unborn child" on products sold in the European Union. 11 other substances in the glyme family are chemically similar, but have no data to discourage the assumption that they might be similarly hazardous.
Now EPA has proposed a SNUR to regulate significant new uses of 14 glymes. What does that mean? Glyme also goes by the names monoglyme, dimethyl glycol, ethylene glycol dimethyl ether, dimethyl cellosolve, and DME. Over a million pounds of glyme are sold in the USA annually, but it is generally considered that exposure to humans is limited. It is used, for example, in sealed lithium battery packs. Additional applications in glyme's wide range of uses include the controversial practice of hydraulic fracturing, or fracking.
Diglyme, which is used in printing inks, may have higher exposures, but EPA points out that no one is really certain. Ethylglyme has no known consumer uses, but it is starting to be found in water sources.
The crazy thing about regulating chemicals with a SNUR, or Significant New Use Rule, is that even with the regulation we will still not know how much exposure people currently have to these potentially harmful chemicals. A SNUR requires anyone thinking of a "new use" to tell EPA about that use and its potential exposures. All of the "existing uses" continue to fly under the radar.
Which is not to say that EPA has been sitting on their hands. In March of 2008, EPA published risk prioritization documents and started asking around amongst manufacturers to understand the scope of uses and exposures. It has long been the practice of EPA to work informally with companies, and a number of chemicals banned by law in other countries have been subject to "voluntary" cessation of supply after EPA made it clear that continued supply could only lead to bans and lawsuits.
So the new SNUR is really about making sure that things do not spin out of control while EPA continues to evaluate whether there is an unacceptable risk related to the 14 glymes. In the meantime, industry is on alert: the EPA could get tougher on Glyme before its over.