Bill,<br>I do carry Potassium Permanganate in my PSK. In my recent post on Potassium Permanganate (sorry I have not figured out how to link this here) I discussed my understanding of the various uses for KMnO4 and ended up concluding that I would carry it...I have convinced myself that the firestarting aspects make it worth carrying. I am a Chemist so these kinds of chemical reactions are "neat". This reason really does not hold up very well in a detailed analysis, but I still carry it. <br><br>I would use it as a fallback water purification method only if ALL my other options were unavailable. The EPA link posted by Tom certainly backs this up. There are far better options with more proven efficacy for the "bugs" we should be concerned about.<br><br>I have evaluated my risks and found that Urban rather than Wilderness use for water purification is more likely. Given that I carry Potable Aqua at all times in my Vest, and have a mechanical filter and Polar Pure (saturated iodine solution) options in my larger gear collections, I do not anticipate ever having to use KMnO4 as a water purifier. I am still glad to know some of the basics of the use, however.<br><br>Immediately after last years EarthQuake in Seattle, I had to evacuate my worksite. I could not get to my car in the parking garage, and was left with just the things I normally carry. This is the type of event for which my PSK has been designed.<br><br>I like having information on the Cheat Sheet that is not just for the contents of the kit. I think that you should keep brief notes on various water purification options on the Cheat Sheet. In an Urban setting, it is likely I could find bleach, tincture of iodine, and maybe mechanical filters. It is very useful to know how many drops of whatever chemical may work as a water purification technique. Standing under the shade of your Cessna wing in the middle of the Canadian NW Territories .....hum...at least you know you could trim off this small piece of the Cheat Sheet to use for something else . <br><br>As for the Chemical Safety of KMnO4. The dry chemical does present a risk of burn, particularily to the eyes or mucus membranes. It may not be a great choice in Scouts kits for this reason. I know I had this in my Chemistry set as a kid, and had purple fingers. It may not even be available in such kits now. The risks at least need to be understood so each Scout, their parents and ScoutMaster could decide.<br><br>Good Luck<br>Randy<br>