I finally got around to seeing Saw II, in which the killer makes use of nerve gas to slowly kill the victims over a two hour period, if they don’t perish a couple other ways first…hehe. Well I don’t know how accurate the movie was but if a group of people are exposed to nerve gas in amounts minute enough not to kill them instantly, but from which they will eventually die, is their weight a factor in how long they take to die?
First of all, in the enclosed space the people were in (according to what I remember from the preview), you would be talking a truely MINUTE quantity of nerve gas. The LD50 for most nerve agents is low as it is, even assuming its a less-lethal one (comparatively) like Tabun or Sarin. Introducing it into an enclosed space to subjects that have no protective equipment… They’d be dead. In minutes. How was the gas introduced? Was it a single low dose, or a low dose over time, or what?
If it was the former, if it wasn’t enough to kill them in the time they were in there, it wouldn’t have killed them at all.
However, since I havent seen the film, there could be other factors I don’t know about. Do you have any more specifics?
-CynicalGabe
Master’s Candidate, chem/bio weapons nonproliferation.
That depends on why it is going to take so long for them to die and what exactly the agent is.
Nerve agents are normally fast acting once they enter the body but the action can be delayed by several means including delayed absorption or conversion to active form within the body itself.
As an example of the first, the agent can be microencapsulated either in clay particles or with a polymer coating similar to an antibiotic capsule. These lodge on the skin or in the lungs and gradually dissolve releasing the agent itself. In cases like this there’s no particular reason why weight would play any significant role. However very fat or very thin people, having more skin relative to nerve and muscle mass could absorb comparatively larger doses and die sooner, while muscular people have relatively less skin area and hence would absorb lower doses.
As example of the second method, in the 50s the USSR claimed to have produced a nerve agent that was converted into active by the enzymes associated with anaerobic respiration. The idea was that when your troops were surrounded you could bombard the area with this agent and anyone sitting still would be unaffected. Anyone charging at the position would switch to anaerobic metabolism and promptly drop dead as the nerve agent in their system was activated. There are potentially any number of other methods of delaying the action of a nerve agent by conversion within the body, and whether size has any effects would depend on exactly what mechanism you use. It’s certainly conceivable that such an agent could be specifically engineered to affect people sooner or later based on size.
The other factor is what the agent actually is. Anticholinesterase type agents normally have muscle-mass related doses. The more muscle you have the more you can soak up without ill effect, so larger people will tend to die more slowly. Other nerve agents such protein channel blockers are related only to absolute body mass while things like adrenalin mimics largely unrelated to body mass at the scale of humans.
Short answer is, it’s possible for size to play a role, but it doesn’t have to.
Nah, most nerve agents have extremely high LD50s, that’s why we use them as household insecticides. The LD50 for something like pyrethrin or DDT is lower than the LD50 for Coca Cola. You’d need to ingest (not just be sprayed with) dozens of litres of the stuff to die.
Depends entirely in the agent and the formulation. Nerve agent research has come a long way since the days of WWI. You don’t always want to kill the enemy fast and a lot of work has gone into producing formulation with delayed effects.
You really should try to dig out some of the literature on the Soviet poison’s program. I’m sure you’d find it as interesting as I did.
IIRC, it was released slowly through the air conditioning system. Supposedly, it would kill them within about two hours. Also, before all the people even got to the house, they were somehow drugged into unconsciousness, so maybe something else could have been given to them first that made the gas work more slowly.
Cite? Most anti-personnel nerve agents are derived from insecticides such as pyrethrin or DDT, not are insecticides… that’s why we call them insecticides.
According to The Federation of American Scientists, the LCt50 (like LD50, but for Concentration per time exposure) is 30 mg/min - m[sup]3[/sup] for VX inhaled, and the LD50 through the skin is 10 mg/70kg man. These sound much lower than the LD50s for Coke or any other soft drink of your choice. 
Modern nerve agents are nasty stuff - luckily not easy to manufacture or deliver, as the Aum Shin Ryuko attacks on the Tokyo subway demonstrate. Older agents like GA (Tabun) have much higher LCt50s (4 g/70kg man through the skin LD50, 135 mg/min - m[sup]3[/sup] LCt50)… but still, I doubt it’s easy to kill a man with 4 g of Coca Cola. Everyone knows only Fanta kills in those concentrations.
I don’t know anything about which one was supposedly used in the movie, tho - didn’t see it.
I thought that all nerve agents interfered with acetylcholinesterase. What can you tell me about these other two classes?
Well if you watched the movie, the killer made an allusion to the Tokyo subway incident, which would lead one to believe he used Sarin.
The LD50 for Tabun is 400mg-min/m3. The LD50 for VX is 10mg. Nerve agents were discovered through research into insecticides. That doesn’t make them the same thing.
Cite?. Not with nerve agents. If you are trying to incapacitate, you use an incapacitating agent like BZ, and not a nerve agent. Or you use a biological payload and give them something else to worry about. I may be wrong, but I’d like to see one example of a nerve agent with delayed effects. That is, one that will kill after a delayed period of time once the lethal dose has been received.
Trust me. I have.