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Appendix 3: Determination of presence of dangerous substance - Guidance for dutyholders

OC 284/7app3 (para 15)
Back to main paper OC 284/7

You will need to carry out the following two steps:

Check whether the substances have been classified under the CHIP Regulations as: explosive, oxidising, extremely flammable, highly flammable or flammable;

Assess the physical and chemical properties of the substance or preparation and the circumstances of the work involving those substances to see if that can create a safety risk to persons from an energetic event.

Step 1: When dangerous substances are used at work, suppliers must provide you with safety data sheets and the safety data sheet should tell you whether the chemical is classified under the CHIP Regulations as flammable, oxidising etc. Another source of information is to look in HSE's Approved Supply List. This is a list prepared by HSE, which lists many commonly used substances and their classification. If a substance or preparation is classified as explosive, oxidising, extremely flammable, highly flammable or flammable then it is a dangerous substance.

Step 2: You will need to carry out a risk analysis using information about the chemical and physical properties of the substance and the circumstances of the work to determine whether a dangerous substance is present.

The key point here is that it is the combination of the properties of the substance and the circumstances of the work process that needs to be assessed. For example diesel (or other high flash point) oils are not classified as "flammable" under CHIP, yet if they are heated to a sufficiently high temperature in a process can create a fire risk. In these circumstances the diesel oil becomes a dangerous substance for the purposes of DSEAR. On the other hand if diesel oil is only present in storage at ambient temperatures it is not a dangerous substance for DSEAR purposes.

Other examples include substances which decompose or react exothermically when mixed with certain other substances, eg peroxides. Wood, flour and many other dusts are, depending on the circumstances of the work, also dangerous substances for DSEAR purposes. This is because when the dust is mixed in a cloud with air it can in certain circumstances be ignited and explode. Work activities involving grinding or machining are particularly prone to this risk.

If the assessment shows that there is a safety risk to persons arising from a fire, explosion or other energy-releasing event then the substance is a dangerous substance for DSEAR purposes.

Updated 2012-02-21