User blog comment:FairyRaven/Fairy Tail Chapter 398: The Final Duels, Review and Commentary/@comment-18654001-20140901190518/@comment-7418318-20140901221402

Just because Gajeel absorbed carbon from the black water doesn't mean the carbon was the poison.

Besides I doubt that Torafusa, who's all about dignity and thus likely also honesty, would have said they'd die in five minutes if their bodies can just work it out themselves.