The defendant bears the burden of proof on the issue of comparative fault, both who else wrongfully caused plaintiff harm and how much.  In an asbestosis case, this means that the defendant bears “the burden to establish concurrent or alternate causes by proving: that [the plaintiff] was exposed to defective asbestos containing products of other companies; that the defective designs of the other companies’ products were legal causes of the plaintiffs’ injuries; and the percentage of legal cause attributable to the other companies.  So if the defendant appeals from the jury’s assessment of its comparative fault, the question becomes whether the appellant’s evidence was (1) “uncontradicted and unimpeached” and (2) “of such a character and weight as to leave no room for a judicial determination that it was insufficient to support a finding.”