What is the Substitution Principle

The Principle of Substitution states that hazardous chemicals should be systematically substituted by less hazardous alternatives or preferably alternatives for which no hazards can be identified. 

As a basis for protection of human health and the environment from chemicals of concern, the Substitution Principle has several advantages  

It implements the Precautionary Principle. Arguments against the Precautionary Principle commonly centre on what degree of evidence of harm is necessary before action is taken to restrict the use of a substance. When applying the Substitution Principle, it is not necessary to wait for cancers, reproductive disorders or genetic defects and elusive evidence of cause and effect. If alternatives with less hazardous intrinsic properties are available, use of the hazardous substance is not permitted. The potential for harm is then reduced or avoided altogether. 

It will avoid the current paralysis-by-analysis syndrome where we have upwards of 30 000 chemicals on the market that have not been adequately tested. Substitution reduces the need for cumbersome, time-consuming, subjective and data-poor assessments of risk. If an alternative is available which is intrinsically less hazardous, intensive assessment of the original hazardous chemical is unnecessary. 

In many cases, hazard based substitution eliminates the need for notoriously difficult exposure assessment. Persistence and bioaccumulation potential are surrogate measures of both hazard and exposure that can be applied quickly to all chemicals In order to identify those of greatest concern. 

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