DCAN 12: Planning Control for Hazardous Substances
Hazardous substance and controlled quantities
18. The list of substances and controlled quantities for which hazardous substances consent is required is given in Schedule 3 to the Planning (Hazardous Substances) Regulations (Northern Ireland) 1993 [as amended by The Planning (Control of Major-Accident Hazards) Regulations (Northern Ireland) 2000] . Hazardous substances are listed in Column 1 of the Schedule and the relevant controlled quantity is listed in Column 2.
19. The Schedule is in three parts. Part A comprises named hazardous substances, Part B applies to substances which fall within generic categories of substances, and Part C is designed to deal with a situation where a hazardous substance within either Part A or B of the Schedule is, or may be, present in a quantity at or equal to the controlled quantity for that substance only as a result of a loss of control of an industrial chemical process.
20. The substances included in Part A comprise all of the named substances from Part 1 of Annex I to the COMAH Directive. For these substances (numbered 1-32 in the Schedule) the controlled quantity is the lower threshold quantity specified in the COMAH Directive except where the same substance was previously subject to hazardous substances consent at a lower controlled quantity. In these cases the lower controlled quantity has been retained. Part A also includes a number of hazardous substances (those numbered 33-63 in the Schedule) not included as named substances in the COMAH Directive. These are substances which would generally fall within one of the categories of substances specified in Part 2 of Annex I to the COMAH Directive (Categories of Substances). However, these substances have previously required a hazardous substances consent at controlled quantities lower than those which will apply to the categories of substances to which they would belong. Therefore, to ensure there is no diminution of existing health and safety standards, these substances are being included as named substances and at the controlled quantities which have previously applied. As an example, hydrogen selenide (substance no. 35) is included as a named substance with a controlled quantity of 1 tonne, the level at which consent was formerly required. If it is considered within its category of substances (toxic) a consent would be required only for the presence of 50 tonnes or more.
21. Part B includes all of the categories of hazardous substances specified in Annex I, Part 2 of the COMAH Directive. The controlled quantities which apply are the lower qualifying quantities specified in the COMAH Directive for these categories of substances. Hazardous substances which were formerly subject to consent at controlled quantities equal to or greater than the relevant qualifying threshold from the COMAH Directive are included here.
22. Substances appearing as named substances in Part A of the Schedule may also fall into one or more of the categories of hazardous substances in Part B of the Schedule. For example, chlorine is a named substance in Part A with a controlled quantity of 10 tonnes. It also falls within the “toxic” and “dangerous to the environment” categories of substances within Part B of the Schedule which have controlled quantities of 50 and 200 tonnes respectively. In such cases, the controlled quantity for that substance will always be the controlled quantity listed in Part A of the Schedule, for example, in the case of chlorine, 10 tonnes. (See Note 3 to Notes to Parts A and B of Schedule 3).
23. Where a substance which is not a named substance, but is one which falls within one or more of the categories of substances in Part B of the Schedule, the lowest controlled quantity will apply for that substance.(See Note 2 to Notes to Parts A and B of Schedule 3).
24. Part C of the Schedule is designed to deal with a situation where hazardous substances may be present in a quantity at or above controlled quantities only as a result of a loss of control of an industrial chemical process. It provides for the kind of incident which gave rise to the Seveso Directive and the introduction of land-use planning controls in the COMAH Directive. An example of when Part C might apply is given in Paragraph 25.
25. Substances W, X and Y may be used in a chemical process to produce, under normal controlled operating processes, substance Z. Under such circumstances, it is possible there may be no requirement for the operator to obtain a hazardous substances consent. This may be because the substances do not fall within either Parts A or B of the Schedule or, if they do, they are not present at or above their controlled quantity. However, in the event of a loss of control of the industrial chemical process, substances W, X and Y might react differently to produce another substance, S, which is within Parts A or B of the Schedule and at a quantity at or above the controlled quantity for that substance. In this case a consent would be required.
26. It is not intended the Department should grant consent for substances generated during a loss of control of the industrial chemical process. However, there will be a requirement for the operator to obtain a consent for the presence of the substance(s) which, in the event of a loss of control, would result in such substances and quantities being generated. To use the example above, a consent would be required for substances W, X and Y. The controlled quantity for these substances will be the quantity of those substances whose presence might lead to substance S being generated at a quantity equal to or greater than its controlled quantity. It is accepted that it may be difficult for operators accurately to predict the type and quantity of substance which may be generated in the event of a loss of control of an industrial chemical process. But nonetheless it is important that they attempt to do so and, as necessary, obtain a consent.