Assessing the Greenness of Chemical Reactions in the Laboratory Using Updated Holistic Graphic Metrics Based on the Globally Harmonized System of Classification and Labeling of Chemicals M. Gabriela T. C. Ribeiro,* ,† Santiago F. Yunes, ‡ and Ade ́ lio A. S. C. Machado § † REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciê ncias da Universidade do Porto, Porto 4169-007, Portugal ‡ Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianó polis, Santa Catarina, Brasil § Departamento de Química e Bioquímica, Faculdade de Ciê ncias da Universidade do Porto, Porto 4169-007, Portugal * S Supporting Information ABSTRACT: Two graphic holistic metrics for assessing the greenness of synthesis, the “green star” and the “green circle”, have been presented previously. These metrics assess the greenness by the degree of accomplishment of each of the 12 principles of green chemistry that apply to the case under evaluation. The criteria for assessment were based on the hazards symbols used in the system established by the European Union, directive 67/548/EEC, obtained from the safety data sheets of chemicals. Meanwhile, the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) replaced that system and introduced a new classification of hazards and new symbols. The objective of this work is to present new criteria for the construction of the metrics based on the GHS system. A brief presentation of this system is included. The present upgrade also includes an improvement of the graphic presentation of the green star to facilitate the visual assessment of the degree of accomplishment of each green chemistry principle. KEYWORDS: High School/Introductory Chemistry, First-Year Undergraduate/General, Second-Year Undergraduate, Safety/Hazards, Green Chemistry, Reactions, Synthesis I n previous articles, two graphic holistic metrics, “green star” and “green circle”, 1-5 for assessing the greenness of synthesis were presented. These metrics assess the greenness by evaluating the accomplishment of each of the 12 principles of green chemistry that apply to the case under evaluation. For assessment of the greenness of synthesis reactions, the construction of the metrics begins by an inventory of all the substances involved-feedstock, products, byproducts, solvents, catalytic reagents, and so forth. Next, information is collected on the hazards to human health, the environment and the potential chemical accident for each substance, as well as information to assess whether the substances are renewable and break down to innocuous degradation products. To construct the metrics, the hazards of the substances involved are generally obtained from safety data sheets (SDS), and scores are attributed to the hazards according to predefined criteria. The criteria were based in the hazards symbols used in the system established by the European Union, directive 67/548/EEC, 6 commonly included in SDS. Meanwhile, the Globally Harmonized System of Classi fication and Labeling of Chemicals (GHS), 7 established by international mandate in the 1992 United Nations Conference on Environment and Development, started to be used. GHS introduced a new classification of hazards and new symbols and prescribed a more systematic lay-out of SDS (under 16 headings) to transmit the hazard information. 7 To adapt the metrics to this change, they were now revised as reported here. New criteria to score the accomplishment of the principles according the new classification of hazards of substances had to be defined because a “direct translation” between the systems in the two regulations is not possible. The objective of this communication is to present these new criteria and examples of their use. The utilization of GHS for the construction of these metrics presents advantages such as (i) a more systematic assessment of the hazards of chemicals for use in evaluation criteria, due to the increased systemization of hazards in GHS, which makes easier the construction of the metrics; (ii) increased contact with GHS in the laboratory context, 8,9 following its recent legal adoption in the U. S.; 10 and (iii) further contact with SDS, that acquired increased importance as a consequence of their prominent role in REACH (Registra- tion, Evaluation, Authorization, and Restriction of Chemicals) 11 for transmission of hazards. At the present stage of adoption, GHS is probably still poorly used by U. S. teachers. The next section provides a brief overview of its most relevant practical contents to make easier its use in the academic context. ■ GHSAN OVERVIEW GHS is a result of the 1992 United Nations Conference on the Environment and Development where a resolution was agreed to protect environment and the human health regarding Published: August 25, 2014 Article pubs.acs.org/jchemeduc © 2014 American Chemical Society and Division of Chemical Education, Inc. 1901 dx.doi.org/10.1021/ed400421b | J. Chem. Educ. 2014, 91, 1901-1908