About CLP Classification from First Principles

CLP classification from first principles is used to classify substances and mixtures on the basis of test data, for most hazards, and human experience for some specific health hazards.

Normally, substance classification is carried out during the REACH registration process for novel chemicals, or when existing substances are registered.  However, in some circumstances, such as a novel substance unique to your company, or where you have a substance with impurities which mean it may have a different classification to the REACH-registered substance, or where you have new test data for one or more hazards, this method of classification may be useful.

It can also be used where mixtures have been tested for specific hazards.  In fact, classification from first principles is preferred above other mixture classification options such as using “bridging principles” to read-across to similar mixtures; or classifying on the basis of component concentration.

To classify a product from first principles, the sequence is:

  • describe the product: either substance name, identification numbers and physical format, e.g. gas, liquid, solid (massive or bulk solid, powder, prills, crystals, paste, gel, etc); or mixture trade name, and all mixture components which might affect the hazard classification of the mixture
  • identify all possible hazardous properties, ruling out those which are not credible (e.g. most inorganic substances are not flammable)
  • identify the hazardous properties where test data exists, and check that the tests are valid.
  • work through the methodology in the CLP regulation for each hazard category, and assign a classification to each one (or note that it is “not classified”)
  • classify for any EUH label hazards, which are only found in CLP and not in GHS
  • keep all your notes and workings for 10 years from the date of last supply of the substance or mixture
  • once a product has been classified, the label information can be generated, and then the SDS compiled

CLP substance or mixture classification from first principles (click on image to enlarge it).

You can also download this flowchart as a pdf: CLP product classification from First Principles .

To help you go through this process, we have created a number of downloadable forms.  Simply print off the form(s) required, fill them in, and they will provide you with a record of the product classification and how you arrived at it.  These can then be used as your record of classification, along with all your supporting documentation.

How to use the forms

Download a copy of the summary form, and once you have filled it in, download the other forms required for classifying your product (there is one for each hazard type).  Work through each form, taking notes (and attaching any supporting evidence or calculations to each form as you go).  When you have classified each hazard, fill in the result on the summary form.  The information on the summary form can then be used to generate the labelling information.

Summary forms for CLP classification from first principles

This form has two functions, to help you identify relevant hazards of the substance or mixture, and to enable you to list all of the actual hazard classifications once you have gone through the classification process: Classifying products from First Principles summary form.

CLP hazard forms – classification from first principles

Physical hazards: https://ttenvironmenta.wpengine.com/clp-knowledgebase/clp-physical-hazard-classification-from-first-principles/ .

Health hazards: https://ttenvironmenta.wpengine.com/clp-knowledgebase/clp-health-hazard-classification-from-first-principles/ .

Environmental hazards: https://ttenvironmenta.wpengine.com/clp-knowledgebase/clp-environmental-hazard-classification-from-first-principles/ .

After classifying the substance or mixture from first principles

Once you have classified the substance or mixture for CLP-GHS hazards, you should:

Leave A Comment

Access to the CLP Knowledgebase is restricted to people who have completed our CLP training course in person or online (coming soon), or other competent professionals. For more information on our next live training course, or to request access to the CLP Knowledgebase, please email us.
Access the CLP Knowledgebase
Sign InSign In