nowhere does it say a single sunburn will cause cancer. if you read your quote it says a sun exposure pattern of brief intense exposure is associated with melanoma.
i am all for sun protection but to claim one day of sun exposure as the cause of your skin cancer and then to use this as a basis for claiming damages in a law suit is just laughable.
Actually, two of the three citations do refer to a single episode:
"a history of severe sunburn at any time in life"
"The sun exposure pattern believed to result in melanoma is that of brief, intense exposure a blistering sunburn"
I will give you that the second quote could be read to be referring to more than one sunburns. And while my other response to you should better address the question of cause and effect, I think that you may be missing the point.
EVERY malignancy starts with a single mutation in a single cell at a single time resulting in a line of cells that divides without the normal controls on growth. So just because you don't get lung cancer from the first cigarette you smoke, that has more to do with the statistics of cell injury than anything else.
So the bottom line is that of I could never in a court of law testify that without a doubt this sunburn resulted in that melanoma - no one could. That is an impossible bar to pass. But the law doesn't require that sort of proof. It just requires demonstration of probable proximate cause. And for that discussion, you will need to hear from the legal moderator..