case: The refrigeration system at Woolworths Supermarket in Armidale NSW broke down in January 2021.

The management at Woolworths Supermarket contact Chris who is a specialist refrigeration mechanic. Chris attends the job and everyone at Woolworths is relieved to see 'their mechanic' has once again fixed the problem. Unfortunately, Chris was in a hurry to finish the job. He therefore fails to correctly affix one of the fridge doors which he took off as part of his service.

After Chris finishes his work on the fridge door, Marjory, who is a regular customer at Woolworths, opens the aforementioned fridge door in order to grab a bottle of milk. Whilst she is doing so, the fridge door falls off causing her significant personal injuries including lacerations to the head.

Chris works consistently at Woolworths Supermarkets four (4) days per week. He wears a uniform supplied by the supermarket. His tools are supplied by Woolworths Supermarkets. He works for other companies when he is not working for Woolworths to supplement his income. Woolworths Supermarkets does not pay taxation on Chris' behalf.

The way in which courts determine the standard of care in any given situation is governed by Mason J's decision in the leading High court case, Wyong Shire Council v Shirt (1980) 146 CLR 40; 29 ALR 217. The court must consider the 'negligence calculus'. That is, the court must consider all the factors which would influence a reasonable person whether or not to take precautions to avoid the risk of injury.

These factors include:

• the probability of the risk materialising
• the gravity of the harm if it were to materialise
• the practicability of precautions
• the social utility ( or "justifiability")of the defendants conduct
• other factors, such as any conflicting responsibilities

Question) With regular reference to the Wyong Shire Council v Shirt (1980) case, explain how the risk of injury caused by Chris did indeed satisfy all these factors and therefore as an employee, Woolworths is held liable for negligence.