I think the bit I have highlighted is the bit that jumped out at me the most. By no means am I suggesting that diesel fumes are good for anyone, but it appears that Unite have created a story here based on this being a possible cause of these unfortunate people getting this vile disease. Hasn't it been reported previously that the UK had reached rates of 1 in 2 people being likely to contract a form of cancer in their lifetime? The improvements in cancer research and the development of treatments has been staggering over the years but it will take generations before it can be completely controlled (if that ever becomes the case) and unfortunately that means we will all be faced with it in one way or the other during our lifetimes - whether that be our own battle or helping others through theirs.
Yes, its horrible and yes we all should do whatever we can to reduce the likelihood of ending up with it, but I can't see how people can lay the blame entirely at the door of one organisation/industry and I definitely can't see it holding up on a legal level.
The reason for the proportion rising to 1:2 is mostly around increased longevity rather than any increase in cancer frequency, if that makes sense?