I received the following query from a client recently:
“At what point does a chemical have to be named as an ingredient on a safety data sheet (SDS)?”
It’s a simple question but it requires a complicated answer!!
Users of substances and products that are mixtures of several different substances need to know what they contain if they are to make a proper assessment of the risks and decide on what control measures need to be implemented. However, suppliers are often reluctant to disclose the exact make up of mixtures for commercial reasons. They don’t want their competitors (and sometimes their customers) to know the composition of their products. In some cases they may be reluctant to declare the presence of a hazardous minor ingredient as they are concerned that customers may be put off from purchasing the material.
A few years ago I had a case where a supplier did not disclose the presence of an isocyanate pre-polymer in the hardener component of a two-pack a polyurethane paint because they did not consider it to be hazardous. Pre-polymers still have active isocyanate groups and exposure to them could lead to respiratory sensitisation and asthma in some individuals. Their argument, when I spoke to them on the telephone, was that the pre-polymer wasn’t volatile and so vapours wouldn’t be given off. That may have been true, but this paint was being sprayed and workers could inhale mist containing unreacted isocyanate, which would have been a significant health risk. The users needed to know that the isocyanates were present in the paint as this would be a major consideration when deciding on appropriate control measures.
Until recently the provision of information to users on labels and SDSs were both covered by the Chemicals (Hazard Information and Packaging for Supply) Regulations (CHIP) . Recent changes in the legislative framework in Europe means that labelling is subject to the Classification Labelling and Packaging (CLP) Regulation, which is being implemented in the UK by CHIP 2009*, while the requirements for Safety Data Sheets are set out in REACH*. These Regulations are complex and can be difficult to interpret and different suppliers may take different approaches to what they will disclose.
In essence the more toxic the substance, the more likely that it’s presence will be declared at a low level on the SDS. However, the information provided does depend on the supplier, as REACH does not require them to declare all the ingredients in a mixture.
With mixtures containing “dangerous substances” (as defined by the CLP Regulations), suppliers are expected to list substances classified as such, together with their concentration or concentration range in the mixture. The “trigger” concentration normally depending on the criteria in the CLP Regulations used to determine whether a substance is classified for a particular hazard. So, for example, a carcinogen should be declared if it is present at a concentration greater than 0.1% by weight. The mixture would have to be classified as a carcinogen under CLP if this amount was present and users would need to know why the product had been classified as such. However, with an irritant, it is possible that it may only be declared if the concentration is greater than 1% or 5%.
At the end of the day, what goes on a data sheet depends on the supplier. In my experience there are very few that are good quality. I don’t expect that to change with the new legislation as its very difficult for Regulators to enforce the requirements in practice.
* CLP is being phased in gradually. For further details see my previous post here
** The Registration, Evaluation, Authorisation and Restriction of Chemicals
Recognition, Evaluation, Control 