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Key Summary: Substance classification is the assignment of a chemical to the hazards it presents. Under the European CLP regulation (the EU implementation of the global GHS), every substance is given hazard classes, H-statements and pictograms. For occupational hygienists, that classification drives prioritisation: CMR substances (carcinogenic, mutagenic, reprotoxic) fall under a strict regime, substances on the SVHC candidate list call for substitution, and where no formal exposure limit exists a DNEL or kick-off value can guide the exposure assessment. The articles below explain each link in that chain, from reading pictograms and H-statements to judging the reliability of the classification source itself.
The DOHSBase Knowledge Base brings together the classification topics an occupational hygienist needs day to day. Start with the basics of GHS/CLP and work towards the specific regimes for CMR substances and substances of very high concern.
Articles in this cluster
- Evaluating classification sources — why the harmonised list is a legal minimum, and your duty to assess every reliable source.
- GHS Hazard Pictograms: complete reference — the nine hazard pictograms and what they mean.
- H-Statements: complete reference — every hazard statement set out in full.
- CMR Substances — carcinogenic, mutagenic and reprotoxic substances and their regime.
- SVHC and the REACH Candidate List — substances of very high concern and the duty to substitute.
- DNEL vs OEL: understanding the difference — when to use a REACH DNEL and when an exposure limit.
- How to find and apply a DNEL — a step-by-step guide to locating and using a DNEL.
- Australian GHS Classifications — how the Australian system compares with the European one.
Related: the limit-value hierarchy shows how a classification feeds into choosing the right exposure benchmark.
In DOHSBase Online, the GHS classifications of 325,000+ substances are reviewed by registered occupational hygienists, with H-statements, CMR status and the underlying source given per substance.