The substitution is possible in the future, it should be possible, where possible, to have a lower impact on the environment. An example of a strong, hazard-based interpretation of the principle in application to chemicals is that „Hazardous substances should not be identified“. 
The principle has been historically promoted by environmental groups. The concept is becoming more mainstream, being a key concept in green chemistry and a central element of EU REACH regulation.  Criticism of the principle claim is very difficult to implement in reality, especially in terms of legislation . [ quote needed ]
Nonetheless, the concept is an important and a key driver in the identification of substances and the development of hazardous substances in the SIN List and the ETUC Trade Union Priority List . EU-funded projects such as the following are under development for the safer substitutes for hazardous chemicals. 
- Jump up^ Greenpeace, (2003, 2005). Safer Chemicals Within Reach: Using the Substitution Principle to drive Green Chemistry. London. p.7(PDF)
- Jump up^ European Commission website on REACH. http://ec.europa.eu/environment/chemicals/reach/reach_intro.htm
- Jump up^ Lissner L, Romano D. Substitution for Hazardous Chemicals on an International Level-The Approach of the European Project „SUBSPORT“. New Solut. 2011 Jan. 1; 21 (3): 477-97. PubMedPMID 22001043.