Practicable having regard to -
| a) | the severity and scope of the hazard or risk concerned; |
| b) | the state of knowledge reasonably available concerning that hazard or risk and of any means of removing or mitigating that hazard or risk; |
| c) | the availability and suitability of means to remove or mitigate that hazard or risk; and |
| d) | the cost of removing or mitigating that hazard or risk in relation to the benefits deriving therefrom. |