What is the chemical similarity between pesticides and chemical weapons?

Question

Back in 2003, 3rd infantry and 101st Airborne Div. soldiers kept finding oddly shaped barrels of chemicals that field-tested out to be sarin, tabun, and other blister and nerve agents. The government later said that it was all simply very concentrated pesticides.

Now, back in the 60's when I was a hippie writing nasty letters to our congressmen trying to get DDT and other pesticides banned, we used the argument that they were just watered down chemical weapons.

So, just how concentrated do pesticides have to be before they can kill a human being? Can they possibly be used as chemical weapons? And while we're on the subject, if Timothy McVeigh killed all those people with gas and fertilizer, and the 9/11 terrorists basically used jet fuel, what exactly is the kill ratio required to get that WMD label?

Answer 1

Depends on the pesticide. There are several different types of chemical warfare agents, and some of the classes have great chemical similarity -- as well as similar toxic mechanisms -- to some popular pesticides.

For example, parathion and malathion are very similar in chemical structure to the G-type nerve agents, like sarin and soman. Both are classified as organophosphorus compounds, with the pesticides substituting a sulfur atom for one of the oxygens in the nerve agents. And yes, if you drink enough malathion or parathion, it will kill you. Of course, the same thing can be said about water or milk. It is the dose that makes the poison.

Both types of organophosphates inhibit acetylcholinesterase, but the pesticides are far safer to use because their LD50 values are so much higher than the nerve agents. For example, the LD50 for malathion is ~370 mg/kg, while the LD50 for sarin (GB) is <0.5 mg/kg. And to confuse the issue, the organophosphorus pesticides will cause the same type of response with typical unit field chemical agent detectors (M256 and CAM) as will the nerve agents.

Now, DDT is a whole different matter -- it is an organochlorine pesticide. It inhibits cholinesterase like the nerve agents, but chemically it is a very different beastie and the exact mechanism is dramatically different, and DDT is dramatically less toxic to humans (LD50 = 1930 mg/kg) than to insects. The concern with DDT is the bio-accumulation problem.

So, it is not necessarily the *strength* or *concentration* of a chemical that earns it the WMD appelation, but the types of results you get by the deployment. The ANFO bomb McVeigh used on the Murrah building gets the WMD label because of it's size and blast radius. Same with a nuke. But chemicals don't have the same kind of "bang" -- more likely a pop or hiss. The difference there is that the agent vapors travel downwind from the point of origin, and anybody exposed is a potential casualty. When you figure you could, under the right weather conditions, have a toxic cloud travel tens or hundreds of miles and still kill, the potential exposed population is what earns it the WMD tag.

Answer 2

Dave Stark nailed it (I work for the Navy in the CBRN area). Many factors go into the label "WMD", but I would propose casualties per munition. Since there can be orders of magnitudes of a difference between CW agents and pesticides, I don't think pesticides could really be classed as WMD. A railroad car of liquid ammonia or chlorine wouldn't either, but it would be something to take very seriously. CW weapons can go from a smallish area (on the order of a kilometer) to maybe 10 km downrange. Biological weapons can go a hundred or more kilometers if the wind is blowing in the right way.

Answer 3

Many organophosphorus compounds are chillingly similar to nerve agents and pesticides.

Generally pesticides would make very poor chemical weapons as the effects are slow and very vague.
What is a WMD? Well if anything happens to kill you then that is your own personal WMD ! In the end it is down to politics.

Unfortunately here in the UK we do not know what to think any longer as Blair concocted lies to tell us about WMD. Think of the Iraqi deaths that have come from that and you suddenly realise that the most potent WMD to date is Blair's lies

Answer 4

To the bugs' insecticide is a WMD. For us it would be anything that can indiscriminately kills every one exposed to a lethal amount of it. Or any device or contrivance that causes loss olf life over a wide area and not a specific target (and / or adjacent area.
I suppose trusting the Government to tell the truth or not abuse power or manipulate public opinion and promote it's own agenda may also result in WMD type casualties and loss of life.

Answer 5

both chemicals has a role on what called biochemical reactions but that can very as far as the porpose of such chemical, it can effect enzimes or so essintial fluids inside any kind of life ,,insects,, animals and mankind ,, each kind of life has its proper biochemical and enzimetic system, also some of these chemicals has different effects,, you can find in market insectcides which can kill flys but not rochs etc. so all these chemicals can be called biocides (LIFE- END).