In an article published on March 13, 2015 in the peer-reviewed journal Science, Julie Zimmerman and Paul Anastas from Yale University, U.S. discuss how “regrettable substitutions” of one chemical with another of equal, or even higher risk, may be avoided. Several examples of regrettable substitution are discussed such as bisphenol A (CAS 80-05-7) replacement with potentially equally harmful bisphenol S (CAS 80-09-1). In response to a growing number of such regrettable substitutions, the U.S. National Research Council released a report calling for “informed substitution”. As the U.S. Environmental Protection Agency notes, informed substitution shall minimize the likelihood of unintended consequences that often emerge when one does not completely understand the profile of the replacements. For informed substitution, an alternatives assessment, a process of comparing functionally equivalent chemicals, is needed. The problem is that such assessments often only consider commercially obtainable substitutes. Yet, in many cases, alternatives that can perform the same function and have a favorable toxicity profile have not been invented. The authors point out that one route to chemical products and processes that eliminate or reduce the usage of hazardous chemicals is provided by green chemistry. They stress that there are already examples of chemicals that were designed using green chemistry principles, which include, for instance, avoiding specific undesirable aspects of chemicals (e.g., persistence). The authors nevertheless emphasize that the number of examples of systematic design for reduced hazard will remain limited until we routinely view the task as a systems issue. Substantial resources need to be devoted to the molecular designs of safer chemicals. Only through this process, future regrettable chemical substitutions can be avoided, the authors conclude.

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Zimmerman, J.B. and Anastas, P.T. (2015). “Toward substitution with no regrets.Science 347, 1198-1199.