Risk Analysis DOI: 10.1111/risa.12507 The Architecture of Chemical Alternatives Assessment Kenneth Geiser, 1 Joel Tickner, 1,* Sally Edwards, 1 and Mark Rossi 2 Chemical alternatives assessment is a method rapidly developing for use by businesses, gov- ernments, and nongovernment organizations seeking to substitute chemicals of concern in production processes and products. Chemical alternatives assessment is defined as a process for identifying, comparing, and selecting safer alternatives to chemicals of concern (including those in materials, processes, or technologies) on the basis of their hazards, performance, and economic viability. The process is intended to provide guidance for assuring that chemicals of concern are replaced with safer alternatives that are not likely to be later regretted. Concep- tually, the assessment methods are developed from a set of three foundational pillars and five common principles. Based on a number of emerging alternatives assessment initiatives, in this commentary, we outline a chemical alternatives assessment blueprint structured around three broad steps: Scope, Assessment, and Selection and Implementation. Specific tasks and tools are identified for each of these three steps. While it is recognized that on-going practice will further refine and develop the method and tools, it is important that the structure of the assessment process remain flexible, adaptive, and focused on the substitution of chemicals of concern with safer alternatives. KEY WORDS: Alternatives assessment; chemical alternatives assessment; chemical substitution; func- tional use; safer alternatives 1. INTRODUCTION During the 1990s, the Massachusetts Toxics Use Reduction Institute (TURI) worked with the Commonwealth’s metal-working companies to reduce the use of the solvent trichloroethylene (TCE) in metal-degreasing operations. TCE is a known carcinogen and neurotoxicant as well as a common constituent of hazardous waste from metal-working shops. Working together, TURI and the companies identified a wide range of substitutes for TCE by performing hazard, performance, and cost assessments of the alternatives. After many of the companies adopted the preferred alternatives, 1 Lowell Center for Sustainable Production, University of Mas- sachusetts Lowell, MA, USA. 2 Clean Production Action, Medford, MA, USA. ∗ Address correspondence to Joel Tickner, Lowell Center for Sus- tainable Production, University of Massachusetts, Lowell, MA, USA; joel_tickner@uml.edu. the state documented a 97% reduction in TCE use in the metal-working and fabrication sector. (1) Beginning in 2007, Hewlett Packard (HP) be- gan to phase out the use of brominated flame retar- dants in its laptop housings. With the incentive of the E.U. restrictions on brominated flame retardants, HP launched an intensive effort to identify safer flame retardants by requiring suppliers to perform hazard assessments of the alternatives. Because the substitu- tion of one chemical for another can cost tens of mil- lions of dollars, HP wanted to ensure that the alterna- tives selected would not need to be replaced because they were subsequently found to be hazardous. (2) Both of these cases share a common element: the careful evaluation and selection of safer al- ternatives to a chemical of concern to reduce the use of hazardous chemicals. The Commonwealth of Massachusetts and HP employed “chemical alternatives assessment” to facilitate the transition to safer chemicals in production processes and 1 0272-4332/15/0100-0001$22.00/1 C  2015 Society for Risk Analysis