Background: This section provides a sampling of defintions for green chemistry and sustainable chemistry from authoritative sources to provide some context to the contention of whether or not green chemistry and sustainable chemistry are synonymous (i.e. can the terms may be used interchangeably?). By definition, green chemistry and sustainable chemistry may sound similar if not identical in nature; however, it has been also been contended that a deeper analysis of the scope, focus and point of application of green chemistry helps to delineate it from the broader field of sustainable chemistry.
|Anastas and Warner (1998)|
“Green Chemistry is the utilization of a set of principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture and applications of chemical products.” 
|Michigan Governor’s Executive Directive on Green Chemistry|
““Green chemistry” means chemistry and chemical engineering to design chemical products and processes that reduce or eliminate the use or generation of hazardous substances while producing high quality products through safe and efficient manufacturing processes. Green Chemistry is based upon [the 12 Principles of Green Chemistry]*.” 
(*Note: The 12 Principles of Anastas and Warner are directly incorporated into and referenced in full within the definition used by the Executive Directive.)
The State of Michigan Green Chemistry Program has further delineated the definition and scope of green chemistry based on the recommendations of the Michigan Green Chemistry Roundtable, available here [PDF].
|American Chemical Society (ACS) Green Chemistry Institute|
“Green chemistry is the design, development, and implementation of chemical products and processes to reduce or eliminate the use and generation of substances hazardous to human health and the environment.” 
|United States Environmental Protection Agency (US EPA) Green Chemistry Program|
“Green chemistry, also known as sustainable chemistry, is the design of chemical products and processes that reduce or eliminate the use or generation of hazardous substances. Green chemistry applies across the life cycle of a chemical product, including its design, manufacture, and use.” 
“Green chemistry consists of environmentally friendly, sustainable chemicals and processes whose use results in reduced waste, safer outputs, and reduced or eliminated pollution and environmental damage. Green chemistry encourages innovation and promotes the creation of products that are both environmentally and economically sustainable.” 
|Organization for Economic Cooperation and Development (OECD)|
The Organization for Economic Cooperation and Development (OECD) defines sustainable chemistry, also referenced as green chemistry, as "...the design, manufacture and use of efficient, effective, safe and more environmentally benign chemical products and processes." Sustainable chemistry aims to "..maximize resource efficiency through activities such as energy and non-renewable resource conservation, risk minimization, pollution prevention, minimization of waste at all stages of a product life-cycle, and the development of products that are durable and can be reused and recycled.
|European Technology Platform for Sustainable Chemistry (SUSCHEM)|
The European Technology Platform for Sustainable Chemistry (SUSCHEM) builds on the OECD definition (above) to describe sustainable chemistry as:
"Sustainable chemistry … seeks to improve the efficiency with which natural resources are used to meet human needs for chemical products and services. Sustainable chemistry encompasses the design, manufacture and use of efficient, effective, safe and more environmentally benign chemical products and processes." 
Sustainable chemistry … stimulates innovation across all sectors to design and discover new chemicals, production processes, and product stewardship practices that will provide increased performance and increased value while meeting the goals of protecting and enhancing human health and the environment.” 
 Michigan Governor’s Executive Directive 2006-6: Promotion of Green Chemistry for Sustainable Economic Development and Protection of Public Health. Available online here.
 American Chemical Society Green Chemistry Institute® (ACS GCI); accessed online August 2011
 US EPA Green Chemistry Program https://www.epa.gov/greenchemistry (accessed March 2018)
 Organization for Economic Cooperation and Development (OECD); accessed online February 2013
 European Technology Platform for Sustainable Chemistry [SUSCHEM]; accessed online March 2018
Are green chemistry and sustainable chemistry the same thing?
Listen to the view point of John Warner in his webinar presented on 8/1/2012 as a part of the Phone Seminar Series on Green Chemistry hosted by the Michigan Green Chemistry Clearinghouse and Great Lakes Green Chemistry Network.