I noticed that several of the survival kits featured on this site include potassium permanganate. Why is this? I beleive that it once used to treat water, but I cannot find any current references to this practice. A web search reveiled that it is poisonous...<br>Any help appreciated.

PP would be toxic I suppose if you swallowed a bunch of crystals undiluted. It has the advantage of offering multiple uses depending upon how much you use in a volume of water. The generally accepted uses are to mix until pink for sanitizing water, deeper pink, more of a rose, to use as an antiseptic, and deep red for use as an anti-fungal. A few crystals go a long way. I pack it mostly to provide an effective antiseptic in a long lived and compact medium. Anything else I consider gravey. The iodine tabs are my primary water treatment. It's not as good as povidone Iodine for antiseptic/medical sterilizing uses, the PI is less traumatic to healthy flesh from what I understand, but it does in a pinch.<br><br>The easiest non-industrial source for PP is tropical fish or aquaculture stores (on the Web as well), it is commonly used to treat some parasitic conditions in fish.

Noted Doug's reply re: water purification, antiseptic, antifungal. SAS book also notes will mark snow for signalling and can be reacted with sugar (e.g. from combat ration) by crushing together small portions of both on a hard surface and will ignite. Also can be ignited by dripping a drop or two of brake fluid or antifreeze onto a half teaspoon of crystals.<br>Hope this is of some assistance - and that I'm not telling you something you've heard already!

Having looked at earlier posts on this topic I see I am "teaching you to suck eggs" as the saying goes - apologies.