Column 1 Hazardous substances | Column 2 Controlled quantity |
| Where it is believed that a substance, which is within Part A or Part B, may be generated during loss of control of an industrial chemical process (“HS”), any substance which is used in that process (“S”). | The amount of S which it is believed may generate, on its own or in combination with other substances used in the relevant industrial chemical process, the controlled quantity of the HS in question. |