CDOIF Guidance

CDOIF

Chemical and Downstream Oil

Industries Forum

CDOIF is a collaborative venture formed to agree strategic areas for

joint industry / trade union / regulator action aimed at delivering health,

safety and environmental improvements with cross-sector benefits.

Supplement to Guideline – ‘Environmental Risk Tolerability for COMAH Establishments’

Complex Site Example v0.0

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environmental impact. The table below provides a summary for some of the site’s inventory. In addition due consideration

has been given to a range of intermediate products, additives and process related chemicals. In particular the potential for

S and HF releases was considered as a result of MAS associated with specific process equipment.

Complex Site

–

Scenario Analysis

Having identified scenarios the next step in the process at the case study site was to utilise the Safety Report to identify

appropriate initiating frequencies for each scenario which could lead to the MAS (central event) occurring.

As noted above, tolerability of environmental impacts is a challenging element within the assessment process. For simplicity

in the case study assessment the CDOIF tolerability criteria were adopted. These criteria are based on the likely spatial extent

of impact at the sensitive environmental receptor and the duration of that impact. In this process there is limited reference to

how harm should be gauged other than through generation of an adverse effect on a receptor or through application of the

definition of ‘

environmental damage’

included in other Regulations. In practice, demonstration (through simulation) of the

adverse effects may be highly complex and potentially disproportionate depending on the probability of a risk occurring at

the receptor in the first place.

The consequence level is then derived by looking up the severity and duration result in a matrix and converting to a

tolerability criteria range as illustrated in Tables 1, 2 and 3 (CDOIF, 2013). The application of the severity criteria is

illustrated in the CDOIF summary tables provided for the case study above. The tolerability criteria were then derived

following consideration of the longevity of impact. This selection was based on expert opinion relating to the fate of the

stored materials in the environment. A medium term impact (1-10 years) was selected for the case study site.

At this stage the other receptors were also reviewed and the potential for different duration/recovery periods was considered

in case this elevated a different receptor as being more sensitive (and with a lower resultant tolerability range). No long term

or very long term durations were identified for the case study site. Further guidance on environmental recover periods for a

range of chemicals is currently in preparation by the Energy Institute and the Institute for Environment and Sustainability

(IES) -