User blog comment:IamJakuhoRaikoben/Chapter 404: 00:00, Review./@comment-4489126-20141011164948/@comment-1776824-20141015015435

Excess amounts of carbon is poison. Carbon-14 is a radioactive form of carbon and will damage the body. You shouldn't have to go full-ham science here, but hypothetically, if Torafusa's waters were laced with carbon-14, then absorption via skin or ingestion would indeed poison everyone. And when you're surrounded by water, it is going inside you at all times.