The Canadian Environmental Law Association (CELA) recently teamed up with U.S.-based Clean Production Action to develop a methodology called GreenScreen for Safer Chemicals (GreenScreen).

 

Greenscreen establishes four major benchmarks for ranking the relative hazard or toxicity of any given chemical expressed in common sense terms. These categories build on the 12 Principles of Green Chemistry developed by American chemists Paul Anastas and John Warner in the 1990s (summarized below).

 

1. Prevention: It is better to prevent waste than to clean up waste after it has been created
2. Atom economy: Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product.
3. Less hazardous chemical syntheses: Wherever practicable, synthetic methods should be designed to generate substances that possess little or no toxicity.
4. Designing safer chemicals: Chemical products should be designed to minimize toxicity.
5. Safer solvents and auxiliaries: The use of solvents, separation agents, etc. should be made unnecessary wherever possible and innocuous when used.
6. Design for energy efficiency: Energy requirements of chemical processes should be minimized.
7. Use of renewable feedstocks: A raw material or feedstock should be renewable whenever practicable.
8. Reduce derivatives: Unnecessary derivatization should be minimized or avoided if possible.
9. Catalysis: Catalytic reagents are superior to stoichiometric reagents.
10. Design for degradation: Chemical products should be designed so that at the end of their function they break down into innocuous degradation products
11. Real-time analysis for Pollution Prevention: Needed prior to the formation of hazardous substances.
12. Inherently safer chemistry for accident prevention: Substances and the form of a substance used in a chemical process should be chosen to minimize the potential for chemical accidents, including releases, explosions and fires.

Since many household and industrial chemicals end up in the municipal wastewater effluent stream, and/or local waterways, this initiative is commendable for trying to address the environmental safety of chemical products.