Circular Economy
Substitution
Definition
Substitution is the replacement of substances of concern with safer alternatives — chemical, technological or organisational. It is a duty embedded in EU chemicals law: REACH authorisation is granted only where no suitable safer alternative exists, and other regimes (pesticides, biocides, occupational safety directives) apply the same logic. Good practice is "informed substitution": assessing alternatives for their own hazards and lifecycle impacts to avoid regrettable substitution — replacing one harmful chemical with another.
References
This reference provides supporting context for how “Substitution” is defined and used.
Source imported for editorial provenance.
Overview
How it is used
The principle structures REACH authorisation applications, safer alternatives assessment, green chemistry R&D, and occupational health control hierarchies.
Why it matters
Substitution is how chemistry gets safer molecule by molecule — provided the replacement is genuinely better, not merely newer.