[Timber Rattler]

What sort of chemical weapons threat was their from either side in the civil war?

Chemical and Biological Warfare in the US Civil War

[Red6]

Your link is broke.

But to answer the question, since you're obviously going to be intellectually dishonest now, there were no nerve, blood, blister, or choking, agents. WWI saw the first real wide spread use of chemical weapons, and Sarin which was the first real nerve agent came out in 1938: http://en.wikipedia.org/wiki/Sarin

No seal on mask = dead.