Having looked at the Sevron website and run their demonstration I have strong concerns about this approach. Firstly it appears to be based solely on the information from the safety data sheet. This is not adequate for COSHH. If you consult the current edition of COSHH it contains the following:-
“Employers should regard a substance as hazardous to health if it is hazardous in the form in which it may occur in the work activity. A substance hazardous to health need not be just a chemical compound, it can also include mixtures of compounds, micro-organisms or natural materials, such as flour, stone or wood dust.” - COSHH ACoP (6th edition), para. 10 - and
“The risk assessment should consider the work activity, including:
All the substances hazardous to health (including biological agents and simple asphyxiants) arising from the work (use, produced, synthesised, created as waste or by-products, or released from processes or during accidents, incidents and emergencies);
Work done by sub-contractors, at the workplace, that may expose employees to substances hazardous to health.” - COSHH ACoP, para. 57
There are literally thousands of chemicals that have never been allocated hazard statements but that, particularly in contact with the skin, can cause damage to health, either through damage to the skin or skin penetration resulting in systemic toxic effects. For example there are over 4,000 chemicals known to dermatologists to be skin sensitisers (Patch Testing. Test Concentrations and Vehicles for 4350 Chemicals, Anton C. De Groot: 3rd edition). The vast majority of these will not have a hazard statement.
The two paragraphs quoted concern themselves with the real hazard that arises when one or more chemicals are used. Mixing, reacting, contaminating, heating, oxidising, etc. will all change a chemical's properties such that the information on the safety data sheet is no longer applicable.
Only a workplace visit to study how the chemicals are used and the consequences will allow you to determine the real hazard on which the risk assessment must be based. Otherwise you stand a risk of damage to health occurring due to an invalid risk assessment.
Chris