Had a nasty FB with poison breath come around and spewed it all over my (beak dog) cavern bait. Miraculously none of the militia I sent to deal with it got hit by the stuff, but every body part of the beak dog that was covered with the FB extract got swollen, then bled, then went rotten and emitted miasma. It survived, but after some months it started going pale, evidence of blood loss caused by infection.
But before it could die of blood loss, an invasion of rodent men appeared and killed it. Two of them had contact with the beak dog and started to show the same symptoms. One had punched, kicked, and bitten it, so all those parts started to swell and rot (because of their huge numbers, I didn't deal with them immediately and temporarily sealed off the caverns, giving time for the symptoms to develop). The other one had punched it so its hand swelled, bled and rotted, but eventually healed itself (rotten body parts can heal???).
Their weapons and shields however also got coated with the poison. Although mere hauling would not cause cross-contamination, I was still paranoid enough to dump it into water in the hopes that the contaminants could be washed off before I melt them. Turns out dumping into water won't remove contaminants, instead the items have to be on a dry tile before water washes over them for the contaminants to be removed.