:red_flag: Bonnington case:
(as applying to the facts in this case)
Essentially, where there is the main cause of dust, but there is a difference between non-tortious dust (the fact that C will likely be exposed to SOME dust whilst working where he was working) and tortious dust (the fact that C was exposed to MORE dust than other employees due to his employer's breach of their duty) is where this test applies
:!: So, the type of dust here constitutes the multiple cumulative causes, but in essence we KNOW it was dust that CAUSED the harm, but not what type of dust - the tortious dust, here, made a material contribution to the harm suffered, despite C not being able to prove which TYPE of dust was the main cause
Material contribution test explored further in Fairchild - here, the courts applied the material increase to the risk test due to the exposure to asbestos which increased C's risk of developing the cancer