Safety Data Sheet (SDS) Authoring

The Classification, Labelling and Packing Regulation (CLP) requires that every chemical manufactured within a territory, or imported into that territory, must be classified prior to first sale. This "classification" process includes the identification, and subsequent documentation (within a standard document called a Safety Data Sheet or SDS), of all the hazards associated with that chemical. It is also necessary to present these hazards on the chemical product itself, by means of applying a prescribed label in a specified format, to the container and any additional layers of packing.

Within Great Britain, substances are required to be classified, for use, in accordance with the Mandatory Classification List (or MCL), as periodically updated by the Health and Safety Executive (or HSE) - at the time of writing this was Revision 5 (of 26th June 2024). This is the "mandatory" classification for any included substance, and is generated following a peer review of the substance dossier, as supplied to the HSE in accordance with the registration requirements of REACH. This mandatory classification must be used for any listed substance, and should be fully documented within the Safety Data Sheet and on the product label.

Following the Classification it is necessary to complete the remainder of the SDS, by using expert knowledge of both the substance and its' specific use to validate, or amend, a standard template.

Section 14 of the Safety Data Sheet contains data regarding a further classification - for "transport" rather than "use", which is completed in accordance with the pertaining transport legislation - CDG2009 (as amended) which implements ADR (with amendments) for national carriage within GB, and internationally without amendments.

Classification of substances not included on the GB Mandatory Classification List, must be justified, and based on good scientific practice and principals, which can include using EU Harmonised Classifications (or HC) , which are generated via a peer review (by the European Chemical Agency - or ECHA) of end point Dossiers supplied to ECHA under EU REACH. It is also appropriate to use data sourced from a supplier SDS, or the Classification and Labelling Inventory (CLI).

The CLI was populated with data prior to REACH Dossier evaluation, and is composed of the original "industrial" classifications of the substance, prior to a peer reviewed "mandatory" or "harmonised" classification being released. The CLI has not been peer reviewed, but does provide a list of "standard industrial classifications".

Mixtures and Preparations

When Classifying mixtures, or preparations, it is necessary to know the exact formulation. The classification process is usually completed by a specialist computer program, but it can be completed manually, and involves adding together the effect that each chemical has in a proportional summation procedure. Each "End Point" is considered in turn, with the summation result compared to the classification steps indicated within the Globally Harmonised System (or GHS) and as reproduced in CLP.

For example if , upon analysis, three components within the mixture are classified as Skin Damaging (under the MCL, HC or CLI) and are in the mixture at 5%, 10% and 15% - then the total of the Skin Damaging "End Point" would be 30% within the mixture. This figure is checked against the GHS to understand the final "Hazard Phrase", "Hazard Statement" and "Pictogram" associated with a "30% Skin Damaging" solution, and that is assigned to the mixture. The same process is repeated for each "End Point" in turn, however for some "End Points", such as flammability, this additive / summation approach is ineffective and laboratory results must be used.

Then appropriate "Precautionary Statements" must be allocated to mitigate the risks indicated by the "Hazard Statements", best practice would indicate up to six "P Statements" as a maximum.

It is to be noted that any laboratory results pertaining to the mixture are considered in preference to the above proportional summation, and checked against the GHS to obtain a classification.

The remaining sections of the SDS are completed as for a single substance.