On the initial read of the report, it should be possible to determine whether or not the site uses safety instrumented systems as risk reduction measures. This constitutes 'key information'.
The information being sought at this stage is not detailed. Ideally, the COMAH report should include a statement that such systems are used on the site. Also, a statement that would satisfy 220.127.116.11 of BS IEC 61511 would be preferred. This requires: "that the company has a policy and strategy for achieving safety in its safety related control systems; that this policy is subject to evaluation; and that the policy is communicated throughout the organisation."
In the absence of the above statements, the assessor will have to use their professional judgement as to whether the equivalent information is present. Reference can be made to this example of a suggested format for addressing C&I issues in a COMAH report as a comparison. Evidence to consider may include:
References to compliance with standards such as BS IEC 61511, BS EN 61508 or similar. (See here for discussion on other standards) ;
Mentions of automatic shut down systems in process descriptions;
If insufficient information is present, the provisions of the SRAM should be followed. The guidance for detailed assessment could also serve as a guide for what information to ask the company to provide.
If the company does not appear to use, or claims not to use, safety-instrumented systems as a part of its MAH prevention strategy, then it is likely to be for one of the following reasons: 1) that they do not need safety instrumented systems; 2) That they use safety instrumented systems but have omitted them from the COMAH report; 3) safety instrumented systems should be in use, but are not provided. Steps should be taken to identify which of these applies. In any case the matter should be discussed with the rest of the assessment team to get a view on the likely need for safety related control systems.
If safety instrumented systems are not needed on the site, the SRAM should be followed to obtain an explicit statement from the site as a request for further information. This further information should include evidence to support the claim, such as results of HAZOP reviews, for example.
If the site does actually use safety instrumented systems, but has not provided any information about them, the provisions of the SRAM should be followed for obtaining further information.
If the site does not use safety instrumented systems, and it is found that they should be used, then the provisions of the SRAM should be followed to determine the need for enforcement action.
If the information described above, or its equivalent, has been provided, the assessor should move on to full assessment.