d20 Modern: Chlorine Gas

[wingsandsword]

As for the difficulty of synthesizing it, it would be a pretty low Craft (Chemical) DC, I'd call it only 13 or 14 (to do so in a controlled fashion).

You can create chlorine gas through the careless mixing of certain household cleaners, I've seen it happen, to very nasty effects, just the intermixing of enough of the cleaners used to clean something can cause nausea, vomiting, irritation, dizzyness, inflammation, lots of bad things. There are actually warning labels on said products about what not to mix with what.

It obviously wouldn't require state of the art labs to create, it was first used as a weapon 90 years ago. It requires chemicals and gear that can be found in almost any chemistry lab (a frightening thought actually).

The problem about chlorine gas, and a big balancing factor in game mechanics about it being a cheap and powerful weapon, is that it's highly caustic and difficult to deploy in a controlled fashion. In fact for any character using chemical weapons, I'd be likely to use the rules for poisoning weapons, a 5% chance of poisoning yourself every time you ready the weapon. That or require a skill check to deploy it successfully as a weapon, my guess would be Knowledge (Tactics) at around DC 20 (since it's a skill you'd pretty much require military training to get, and it's not exactly easy), and a failure means you have exposed yourself to the gas in some way the process of setting/arming/activating it.

 

[radferth]

Chlorine gas is somewhat limited as a weapon, as its smell is so strong and easy to recognize. It does fill low-lying areas, so it works well for closes area and world war I trenches. HP damage/con damge seems like a good way to simulate it. The wounds it inflicts are basically burns, so it would be hard to treat the lung damage. Don't know how any of this helps, except that it makes a better deathtrap than general use weapon.

 

[Committed Hero]

At the risk of sounding dumb, what's wrong with the Mustard Gas entry in the Craft(chemical) skill?

 

[DarkKestral]

Does anyone recall the sarin gas attack by that cult in Tokyo? The gas was released in a crowded subway station and still no one died.

I don't think poison is necessarily that deadly (at least sarin doesn't seem to be). On a similar note, biological warfare has virtually never worked.

I don't think it's necessary to boost the Con damage (you could keep it at one or 1d4, for instance) but increase the DC with Concentration. Obviously the longer you're exposed, the more Con damage you take.

(Psi): Yeah, but dispersal is often a factor with enzymatic actors like sarin and inhalants like mustard gas and chlorine which have short breakdown periods. Sarin, especially, has to hit the lungs almost immediately, or else it breaks down. Sarin is in fact quite deadly when a chemical warhead of appropriate design is used. Most of the major chemical weapons are simply designed to be ideal means of dispersal. Most, if not in a warhead, need some active dispersal system, as most are heavier than air. Otherwise, they may not function to gas one's target.

Furthermore, it's really not THAT hard to design a system for releasing/preventing the spread of it... sealed ductwork and fans will do to spread it where you want it, if you can actively control what regions get air/gas ducted from one place to another. It's not even that unusual to see the basic systems in place in large buildings, for both safety and money reasons. Selectable route ductwork and sealed buildings? Featured in most skyrises, because it makes them safer in an emergency. Chem/Bio labs will almost always have the systems, as will many larger hospitals, and warehouses and factories that use dangerous chemicals will often have them too, for the same reasons. The reasoning is as follows: "We have something dangerous released into the air? Huh. Turn on the active ducting systems to create a vacuum and let it get ducted away to safety or let a fire smother itself without the oxygen it needs, while we evac the building and call the emergency services." (This might be a feature of the Tokyo subway system. I'm not sure. Probably is though, and is possibly a reason no one got killed, though many got injured, and it's supposed to be very well designed and resistant to attack. These sort of systems can easily turn 'deadly' attacks into much less severe events, if used properly.)

wing: Reverse that system, and you now have a deathtrap. It's semi-esoteric knowledge to figure out the construction, though not hard to figure out the basics, if you think it through. Certainly, it's not DC 20 just to ACTIVATE. If there's knowledge of the system in the first place, it would not be hard to have it DC 1 or DC 5. If building a capacity to have a resettable trap, it certainly would be a bit higher DC to craft than the current belief of DC15 or so to build/design a system to make the chlorine and then disperse it, (+5 to the DC sounds reasonable) but it would be a very low DC to activate it, as they are designed to be rather easy to use, to ensure that no one accidentally can't use them when needed. The stronger vacuum versions are designed to be activated only by someone marginally trained in their use, though, since some of them could be deadly. It may not even need human intervention, being armed by a machine w/ a proximity sensor/chemical sensor that monitors the presence of certain chemicals in the room.

Hero: Mustard Gas is similar in effect and purpose, but there are different versions out there of the mustard gasses. Different ones have different effects, and some are more lethal than others. Therefore, it could be better to use something more specialized. It'd do in a pinch, but I'd probably wanna build a more accurate version if I had time. Mustard gas is a more effective toxin, for one thing.

Mustrum_Ridcully: I favor leaning over to the 'realism' side of things when using WMD. Gas attacks are not something I think the PCs should ignore, and they should pause and consider their options when they hear an opponent uses such systems as defense traps. They may be heroic, but unless they've got some Tough Hero talents (Acid Resistance, for one, would be appropriate) and levels under their belt, it shouldn't be something you just shrug off either. I also wish d20 had better capacity to deal with different doses and permanent effect poisons, because many have a kind of 3rd effect that tends to be somewhat permanent. I also believe you can make a balanced poison that has differing effects at differing dosage levels. Just assign a commensurately higher PDC and/or craft DC score and perhaps add a few levels to the restriction score (non-licensed may go to Res (+2) for example) to account for the additional difficulty in acquiring it in large enough dosages. (An example would be Chlorine could be used as Lic (+1) to own in enough quantity to use as a deathtrap, but the more powerful '10 dose' version would have a Craft DC of 22 to build it into a trap, a PDC of 20+, and additional restrictions, making the trap Ill (+4), so if you get caught, you're not just facing a few years of jailtime, but possible execution in some locales) It also doesn't mean you can't have poisons built at differing levels of 'lethality', where some are designed to challenge non-FX players, and some are designed to challenge Future or FX players, and some designed for players using Future+FX rules. (Future and FX rules generally do provide a player power boost. This being the case, to challenge players, you might have to use stronger stuff... there's no reason it can't be provided) Therefore, I deplore the poison rules because they aren't that good, and could be made better while sticking to the 'source material' that defines the genres Modern is designed to emulate, while also being more accurate w/ reality.

This comes from my experience with poisons in real life. I have to take some pretty heavy precautions against them to work with them at all, and honestly, even in action movies, you don't see the heroes 'just shrugging it off' as PCs may be wont to do, but rather, they're coughing, nauseated, weakened... all the things I'm mentioning. Granted, they go ahead anyway, but they aren't really saying "eh, we'll just use an item later to get rid of the effects..." Thus, I favor a sort of 'I'm not gonna pull punches' approach. You want to attack that building which you know has a gas deathtrap system without an enviro-suit? Go ahead, but don't expect to live too long...

 

[takyris]

I worked in a pool supply store one summer. Chlorine gas is really easy to make, even accidentally.

Devil's advocate question: is it really necessary to use a poison mechanic? Why not treat it more like a molotav cocktail?

If you get splashed, it does a little damage (say, 1d6), and anyone wearing a gas mask is safe.

If you get directly hit, it does more damage (say, 2d6) and forces a Fortitude save, DC 15 (I'm making numbers up here -- 1d6, 2d6, DC15, these are all pretty commonly used numbers.). On a failed save, you've inhaled some, and you take another 2d6 damage next round and must immediately begin making saves as though you've run out of air while holding your breath. You keep doing that each round until you make a save or die. (I'm basing this roughly on the "catch on fire" mechanic.) If you make your save, you are no longer choking and don't have to make those checks anymore.

If you're wearing a gas mask, it's only 1d6 for a direct hit, and no additional problems. It hurts, but it's not a killer.

Friends can help you on your save (a +2), and anyone with a Treat Injury check can make a DC15 check to give you a +4.

The damage is considered acid-based for all purposes, including monster vulnerabilities and immunities and the "Elemental Resistance" talent tree.

EDIT: I know that this isn't the most realistic take on it, but it's really fast and really easy to use. Most players can pretty quickly understand "It's a splash weapon with something like catching on fire" and add on "and you choke" without too much trouble.

 

[Nuclear Platypus]

Chlorine gas is water soluble (how it reacts with the body) and I believe in WW1, soldiers would breathe through a wet cloth, which doesn't do much for the eyes. According to wikipedia, some believed breathing through urine soaked cloth worked better (ewww) when its worse since ammonia and hydrochloric acid combination is very bad.

There's other methods of making chlorine gas too as takyris mentioned (a friend of mine can't be around chlorinated pools as a result of a bad experience while shocking one). Another method is how it was synthesized involved brine, (sulfuric) acid and manganese dioxide (by Carl Wilhelm Scheele). Probably before that was the Deacon Process, using cupric chloride as a catalyst. Heck, mixing concentrated muriatic acid with something (like sodium chlorate) is bound to create chlorine gas, in small amounts at least.

As for d20 sources, what about the 1st Edition Green Dragon breath weapon?

It might be better to just handwave it. "You see a greenish cloud drifting towards you, the smell making your eyes water. What do you do?"

 

[ValhallaGH]

On a failed save, you've inhaled some, and you take another 2d6 damage next round and must immediately begin making saves as though you've run out of air while holding your breath. You keep doing that each round until you make a save or die. (I'm basing this roughly on the "catch on fire" mechanic.) If you make your save, you are no longer choking and don't have to make those checks anymore.

You may want to read over the suffocation mechanics again.
Con check, DC 10 + 1 per previous. Failure => 0 hp, followed by -1, followed by dead.

With your proposal it would be 2d6 + DC 15 Fort. Failure => 2d6 + Con check DC 10. Failure => 0 hp, next round -1, next round dead.

So it would deal 2d6, possibly followed by another 2d6, possibly followed by death.

Everyone would throw chlorine gas, since 4d6 + death is a whole lot better than a piddly 2d8 pistol shot.

Personally, I'd just use the stats for Mustard Gas.

 

[Aussiegamer]

the rules for poisoning are not that you are continuely exposed to the gas, ie stuck in the room with the gas, but that you have gotten a dose of it once.

So you could rule that exposure each round is another poisoning dose and thus another save. Thus after a minute you would have been exposed 10 times and had to save 10 times, then you start getting the secondary saves coming in as well. So death would come pretty quickly after a minute of exposure.

 

[takyris]

You may want to read over the suffocation mechanics again.

Heh. Again, he says.

Good points -- I'm in a slow-net, no-books neighborhood, and I didn't look at the numbers.

If I wanted to go with the relatively simple one, then, I'd try:

2d6 Initial Inhalation, Fort DC15 to avoid getting it into the lungs
2d6 each round it's in the lungs, DC15 each round to cough it out
Can't breathe while it's in the lungs -- but you don't have to make the checks until the normal "You're out of air" point.

Or if not breathing is too rough, say that the victim is nauseated until he makes that Fort save and stops taking damage.

That would at least stop the immediate choking and suffocating issue, and it's still fairly simple -- and would wreak havoc if a group of people were caught in a room with the stuff, which is about as it should be.

But yes, as you said, stats for mustard gas are probably fine, too.

 

[HeapThaumaturgist]

Here's what I've got so far.

Poison: Chlorine (Gas)
Type: Inhaled
Save DC: 15
Initial: 2d6 Damage + Nauseated 1d3 rounds
Secondary: 1d4 Con
PDC: 15
Restriction: Res (+2)
Craft DC: 15
Time: 4 hr.

Normal rules for D20Modern poisons. As a gas poison, this is the craft/PDC for building a cannister that will deploy the gas into a 10'x10' area.

A little damage, a little asphyxiation ... not as much Con damage as Mustard Gas, nor as high a save, but not something I want to stand around doing deep knee bends in, by any stretch of the imagination.

A footnote in a sidebar.

--fje