How to get a C.L.U.E. report?

Is there any toxin which not only kills a person but also get metabolized in the process so that forensics and pathology report doesn't provides any clue?

• Answer:

  Ethanol. The LD50, or concentration that kills half the population, of your friendly inebriating drug is about 10.6 grams per kilogram of body weight (1). I weigh about 65 kilos, so to reach the amount of EtOH that would probably kill me, I'd need to consume a little less than 700 grams of alcohol to kill me. Given the density of ethanol at room temperature and sea level (0.786 g/ml), that's about 540 ml of ethanol. Drinking PBR at about 5% alcohol by volume (2), I would need to drink almost 3.5 gallons to kill myself. Not going to happen, which is why it's so much safer to shotgun beer than do shots. Stay safe, kids. But everything changes if instead of drinking PBR, I inhale alcohol. Such a mistake can be made by well-meaning people trying to, say, make jello shots. To make jello shots, one should mix alcohol and water and chill the mixture. When adding hot liquid to dissolve the jello mix, only boiling water should be used, and the alcohol added later (3). This seemingly convoluted way of producing jello shots, instead of mixing alcohol and water and heating the mixture, is done just so for the reason that the crazy party you wish to throw will be much less cool if you die before it starts. While we could do some decent estimation for a vapor-liquid equilibrium of an ethanol-water system while varying temperature and mole fractions using Raolt's Law or be more specific by examining the azeotrope of ethanol and water, I'm writing this on an iPad at the moment. An engineering student doing calculations without Excel is like writing with a broken pencil: it's pointless (heh, heh). Suffice it to say that, since ethanol is more volatile than water, if we have a closed system (like a pot on the stove with a lid on it) and heat it, the resulting vapor will have a lot more ethanol in it than water. If one inhales that vapor, as one might do when pulling the lid off the pot and breathing deeply, one breath of 70+% ethanol vapor is quite enough to exceed the CDC's IDLH limit (Immediately Dangerous to Life or Health), which is a measly 15,000 ppm, or the lethal inhaled dose, which is somewhere above 20,000 ppm for long exposures, or above 2% (4). However, while inhaling a very concentrated ethanol vapor could certainly kill someone, the total amount of ethanol required wouldn't be all that high, and certainly not much more than a determined soul at an end-of-the-semester party could consume. And since the liver could easily metabolize the relatively small amount of ethanol inhaled over a couple hours, vaporized ethanol could be your toxin of choice! But man, what an awful waste of a good vodka. (1) http://m.wolframalpha.com/input/?i=ethanol+ld50&x=-988&y=-71 (2) PBR can being drunk by friend with whom I am facebook chatting (3) http://m.wikihow.com/Make-Jello-Shots (4) http://www.cdc.gov/niosh/idlh/64175.HTML