Toxic Blog#1 -Do you often receive SDS which are inconsistent and confusing?

I suspect that for those of you who receive supplier SDS, the answer to the question will be the same as mine…YES!

On a personal note, I find that inconsistent Safety Data Sheets leads to endless frustration and time wasted contacting suppliers for clarification. Again something which I am certain many of you have also experienced.

Now whilst we are talking about inconsistencies in Safety Data Sheets, another thing I have noticed is that many SDS authors forget to utilise available physicochemical data (Section 9) to help write the other SDS sections.

This is a pity because this kind of information is nearly always available and can really help the SDS author both improve the overall consistency (and therefore quality) of the SDS. In fact, even a basic understanding of physicochemical data can really help SDS authors understand what needs to be written in other relevant sections – rather than leaving gaps, or vague statements.

Physicochemical properties to the rescue!

In this post, I will show you a simple example of how a basic knowledge vapour pressure  (Section 9 – Physical and Chemical Properties), can be used in other relevant sections of the SDS.

[Take a look at the recent  ECHA 2019 report – it makes for very interesting reading  ‘Improvement of Quality of SDS’.]

Vapour pressure – an indication of volatility

Vapour pressure is a useful indication of the tendency for a substance to rapidly evaporate into the air and thereby become an inhalation risk.

Now as a general rule, substances with a boiling point below 50°C, or a vapour pressure  >25KPa would be considered to be highly volatile. A substance with a boiling point greater than  150°C or a vapour pressure < 0.5 KPa, would be considered to be of low volatility. (ECHA, 2017)

Let’s take a look at acetone, which is a highly volatile liquid. It has a vapour pressure of ca 24 KPa (at 20°C), which explains why we quickly smell the characteristic odour once the bottle/container is opened. It also means that we are being exposed by the inhalation route.

How this information can be used – human health

An understanding of vapour pressure and its interpretation can help us predict whether exposure is likely to occur by inhalation and therefore, what precautionary measures we should recommend in other sections of the SDS.

For a substance which is volatile/highly volatile, it would be important to minimise any potential inhalation exposure by means of appropriate engineering controls and respiratory protection (e.g. sections 6,7,8).


We would also need to consider the impact of storing a volatile/highly volatile substance (e.g. Section 7- Handling and Storage) as well as the impact on other sections of the SDS. There are of course other considerations related to physical hazards and the environment.

Now for the purpose of this Toxic Blog, I have only considered vapour pressure, yet there are other physicochemical data (e.g. log Kow, pH, specific gravity, dustiness), which can also provide a useful insight into exposure and hazard.

Being able to interpret physicochemical data makes it possible to write meaningful and useful information in other relevant sections of the SDS. All of which will help improve the overall consistency of your SDS.

Upcoming SDS related webinars

‘Introduction to Writing Compliant (and useful) Safety Data Sheets’ – 19th February 2020. More information

‘Introduction to Toxicology, Ecotoxicology & Physicochemical Properties for Safety Data Sheets’ 25th February 2020.  More information

The focus of these webinars is to not only help understand the regulatory requirements when authoring SDS, but also to utilise the available information from key sections (i.e. toxicology, ecotoxicology & physicochemical properties) to help improve overall consistency.


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