Chemical/Biological Warefare

I would like to see the addition of chemical and biological warfare. We already have nuclear war in the game so why not chemical and biological? This would add an interesting new dynamic to the game once the late industrial/early modern era came around. To my knowledge biological warfare has never been used, at least not in a large scale way with modern technology. But large scale biological warfare is something that theoretically can happen as soon as the technology exists (in real world probably very late 1800's or early 1900's). And chemical warfare was used extensively in WWI and could potentially be used again. The following is how I think they should be implemented into the game.

Biological Warfare: Biological warfare can be used against units, it won't kill them right away though. Since units in Gods & Kings have 100 hit points, if a unit is infected each turn it will lose 10 hit points, even if fortified. This will continue to happen for 5 turns, if the unit was damaged before it got infected there is a good chance it will die before 5 turns. After 5 turns there is a 50% chance that the unit recovered from the disease and can then begin to heal as normal. If the unit does not recover from disease after 5 turns it immediately dies. This adds a new dynamic becasue you have units that are constantly getting damage not matter what you do with them, but you don't want to delete them because they may potentially heal and you can't do without it. Also, units can still fight while infected, they just can't heal and take damage every turn from disease and combat.

Chemical Warfare: With chemical warfare it is basically like artillery, except it affects all units within a certain tile range. It is not as powerful as artillery, it might only take away 10 or 20 hit points, but it can affect a large number of units at the same time with one strike. Certain tiles outlined in red, maybe 4 or something like that, will always be affected. But there is a chance that one or more of the adjacent tiles will have wind blow the chemicals back into that tile, (maybe a 10% chance for every adjacent tile). This simulates what happened in WWI, many times wind blew the gas back onto friendly troops. And you can unintentionally damage your own troops with chemical warfare too if they are located in adjacent tiles (though the chances are small enough that it is tempting to use). The effects of chemical warfare only last 1 turn, after that units aren't affected, they may be damaged but can heal like normal, unlike biological warfare.

I like the idea.

They stopped using chemical weapons because they weren't very effective (except as a terror weapon against civilians). Biological weapons have never really been used. I don't see the need for the inclusion of either.

Bio weapons are a "you kill me, I kill you" scenario, and are actually very much like nukes in that respect. Except much scarier. Supercharge the flu, drop a bomb, instant plague. Add in some antibiotic resisant traits from other viruses, and you looking at a weapon that could decimate an entire continent in a week. Chemical weapons, however, eh.... it hurts like crazy, but it was really meant to soften resistance and impair the enemies ability to fight effectively. Poison gasses are filtered out by gas masks, our forces our trained to resist stuff like mustard gas by being delibrately expsoing themselves to it....the way the OP has fits perfectly, but there should be a counter tech to it(gas masks, reduce chance of it damaging the unit to something like 20%, maybe? or make the damage drop to 2-3 hp. That stuff burns if it contacts skin, it feels like some lit you on fire! Inhale it, your down; let it touch you, you can't focus.) WAIT! That's it! Instead of having it do damge, have chem. warfare weaken forces; give affected units a negative combat modifier for x amount of turns, with an x percentage of them taking damage until gas mask tech is researched! upon researching, your units don't ever take damage, and the negative modifier is reduced(but not eliminated). As for bio, it's a very real threat, one that could become more than a threat in the next World War, and yes, there will be another, the people of this planet CANNOT stay at peace indefinitely, it's a question of where and when the spark is. On a lighter note, can't wait for the expansion!

If they were introduced into the game I think they should work as follows:

Chemical: Target enemy unit (with siege. maybe even a melee unit but with a chance of hitting itself). 50% chance targetted unit is hit. 25% chance of adjacent units to target are hit. Hit unit cannot heal and has -1 movement for one turn. Chance to hit can be reduced by certain techs (gas masks and other equipment)

Biological: Target enemy city (with siege or melee unit. spies would work well here). 25% chance city loses 1 population and cannot purchase or produce for 3 turns. 10% chance city loses 3 population and cannot purchse or produce for 6 turns.

Both weapons would have negative diplomatic repreccussions.

I don't think either weapon will every be introduced into the main game, but with extension of WW1 era units, you never know.

I think if a city is infected there should be a chance that it can spread to nearby cities. I like the idea of losing 1 population, and a 10% chance of losing 3 population. So that wouldn't be too severe if the plague spread to other cities. Potentially the plague could spread worldwide. Like the influenza of 1918 that killed more people than all of WWI. And if you are the civ that casued a global plague, you better believe you will be hated by everyone!

This is something to think about. The chances of a global plague happening from attacking 1 city are small, but there is a chance. And the more bio-weapons are used the greater the chances get becasue there are more infected cities to begin with and they can all infect other cities (including allies and your own) So bio-weapons are not to be used carelessly as there are SERIOUS diplomatic ramifications.

Unpredictability is what makes bio weapons so dangerous. With a nuke there is a blast radius and some radiation, but it's contained and in a short time it's probably safe to live within a dozen miles of the blast zone. There is no way to contain a bio-weapon. Not with 7 billion people on the planet traveling all over the place with airplanes. A global plague that took a few months to spread 100 years ago could now spread worldwide within days.

I like the idea too and think it would make a great addition to the game along side our nuclear capabilities. One of the earliest instances of Bio warfare was by the Russians when they used to catapult dead diseased bodies into Swedish strongholds and chemical weapons have been used in many conflicts within the 20th century (Iran-Iraq War, Vietnam etc.). Who wouldn't like to release a bioweapon into one of Monty's cities? With the new espionage system the introduction of chem and bio weapons/warfare could be great!

Moderator Action: Moved to Ideas & Suggestions.

Given the apparently new WWI era, perhaps there's some sort of pre-Atomic Bomb mustard gas-type thing?

There were cases of biological warefare even in ancient times. But they didn't really understand how it worked. They knew if they did certain things they could make an enemy sick and maybe kill them, but they didn't know why, they had no concept of bacteria or viruses. They just knew it worked so they did it. I think the game should focus on modern bio-warfare. Today bio-weapons are mass produced in laboratories.

There are manmade genetically engineered viruses that could kill 99.9% of the population if they ever got released (it could even be an accident). I think if this ever happens it would be far worse than nuclear war.

Agreed. It's actually worse than some people fear. Most people think it's the bug that'll kill you, but the panic caused by an attack like that will lead to a complete breakdown of society in whatever region the weapon is launched. Even with a suicide chain encoded into the virus's genetic code, the sheer devastation caused by such an attack will crush any and all defenses in a matter of weeks.

I admit I have always wanted to see this implemented.

Perhaps with spies we should be able to have a future patch that could spread a disease in certain cities (with the fact that if it spreads too quickly it could spread to you)

All of these ideas seem to ask for a return of a health system, and a local one at that. These weapons would then cause a loss of health points, and you would have buildings and techs that boost health output.

Bio weapons could affect population growth and effects could stack.

Chemical weapons have been used practically forever. You could start them off as primitive grenadiers and evolve them through to the various mustard gas etc weapons of the recent world

I'm a little surprised that there isn't any Chemical or Biological warefare in Civ 5.

With the addition of WW1, it would make sense to use mustard gas. I think the ability to say pillage a tile with some type of gas bomb would be a good tactic, doing some type of debuff or poison type of damage to anything that stands in it. Or utilize gas bombs to limit the enemy's sight.


Plagues are something that is missing from this Civ game in general. There should be game competent that can affect the production of your city or its growth via sickness. Biological warefare would be an extension of that, and they could even make up weapons by exploiting the Future Age tech tree.

Heart Break Kid said:

I'm a little surprised that there isn't any Chemical or Biological warefare in Civ 5.

With the addition of WW1, it would make sense to use mustard gas. I think the ability to say pillage a tile with some type of gas bomb would be a good tactic, doing some type of debuff or poison type of damage to anything that stands in it. Or utilize gas bombs to limit the enemy's sight.


Plagues are something that is missing from this Civ game in general. There should be game competent that can affect the production of your city or its growth via sickness. Biological warefare would be an extension of that, and they could even make up weapons by exploiting the Future Age tech tree.

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Perhaps they can use an already in game mechanic: fallout. Fallout could represent pollution (I'm thinking Civ 2 here), bio and chem weapons, disease, etc. Mustard gas a tile and it damages units and creates a haze on the tile for X turns or until it is cleaned by a worker. Of course, they could just reintroduce the health system...

Kurtbob said:

bio and chem weapons, disease, etc. Mustard gas a tile and it damages units and creates a haze on the tile for X turns or until it is cleaned by a worker. Of course, they could just reintroduce the health system...

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...And with introduction of Health it would be possible to use Food as a biological weapon as well

Images to explain what I mean: NOT TO BE TAKEN TOO SERIOUSLY (A bit Fallout type black humor)


Overall, I think some kind of Chemical weapons should be introduced to the game. Since it would really give a fresh element to the modern warfare and if I remember correctly there hasn't ever been any kind of Chem/Bio weapons in past Civ* games... (Perhaps there is a good reason for it?). *Well CivII had Poison Water Supply, a Spy mission and SMAC had spread genetically modified virus a Probe Team operation, so perhaps there could be some kind of Espionage element in CiV related to the subject.

civ4 let you poison water with spies and the future mod that came with the game had a unit called chemical weapon or something like that. and in some mods, you could spread plagues, though i can only think of that happening through units and trade routes.