I wonder how attacking individuals in court and casting doubt on the causes of their sickness could be of any use against the larger picture, i.e. against the c

I wonder how attacking individuals in court and casting doubt on the causes of their sickness could be of any use against the larger picture, i.e. against the correlation between leukemia cluster and the TCE contaminated area. I also wonder if another dirty trick would work against such cases, where the plaintiff side throws the burden of proof on the defendant asking for numbers deduced from the costly inquiries and how those numbers explain anything in relation with numbers deduced from a non-contaminated area.