Why Is Tear Gas Banned in War but Still Used by Police?

Every time tear gas appears in the news, I receive the same question.

"If it's banned in war, why can police still use it?"

It's a fair question, and one that sounds contradictory until you understand the history.

Many people assume that if something is prohibited on the battlefield, it must be too dangerous to use anywhere else. The reality is more complicated. International treaties don't prohibit tear gas because it's considered the most dangerous chemical ever developed. They prohibit it because history demonstrated how quickly the use of one chemical agent on the battlefield could escalate into something far more destructive.

During World War I, the progression from relatively mild irritants to chlorine, phosgene, and eventually mustard gas showed just how dangerous that slippery slope could become. When nations negotiated modern chemical weapons treaties decades later, they decided the clearest rule was simply to prohibit all riot-control agents as methods of warfare.¹²

That prohibition, however, doesn't apply to domestic law enforcement.

The Chemical Weapons Convention specifically allows riot control agents to be used for legitimate law enforcement purposes while prohibiting their use as a method of warfare. The distinction isn't based on the chemistry itself. It's based on the intended purpose and the context in which those agents are used.³

That brings us to another question I hear frequently.

What exactly is tear gas?

Despite the name, tear gas isn't actually a gas. Most modern formulations are fine solid particles or liquids dispersed as an aerosol. When they contact the eyes, nose, throat, and skin, they activate pain receptors that cause tearing, coughing, involuntary eye closure, and intense irritation. Those effects are designed to be temporary and to encourage a person to leave the affected area.⁴

Most people don't realize there isn't just one type of tear gas.

For decades, the two most common riot-control agents have been CN and CS.

CN, or chloroacetophenone, is the older chemistry. It was widely used throughout much of the twentieth century and was found in many of the original self-defense sprays sold to civilians. In fact, the original Chemical Mace® introduced during the 1960s relied on CN rather than pepper spray.⁵

CS, or 2-chlorobenzalmalononitrile, arrived later and gradually became the preferred riot-control agent for many law enforcement agencies around the world. Compared with CN, CS generally produces a faster onset of irritation, is more effective at lower concentrations, and has a more favorable toxicological profile when used appropriately. For those reasons, CS has largely replaced CN in modern police applications.⁶⁷

People sometimes ask why our Scorpion Pepper Spray contains CS tear gas instead of the older CN formulation.

The answer is straightforward. Our goal wasn't to recreate products from decades ago. We wanted to build a modern defensive spray using the chemistry that has become the industry standard for riot-control applications. Scorpion combines high-performance Oleoresin Capsicum (OC) with CS tear gas, allowing the inflammatory effects of pepper spray to work alongside the temporary irritant effects of CS. Like every defensive tool, it should only be used when legally justified and only according to the laws of your state.

Technology continues to improve. Manufacturing continues to improve. Aerosol systems, valve designs, and formulations continue to evolve.

Good judgment, however, has never gone out of style.

Long after the chemistry has changed, that will still be the most important safety tool anyone carries.

David's Take

People love talking about products because they're tangible. We can compare specifications, formulas, and features all day long. What deserves just as much attention is the judgment behind the decision to carry them. The right product matters, but the right mindset matters even more.

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Key Takeaways

• Tear gas is prohibited as a method of warfare under international treaty but remains lawful for many domestic law enforcement uses.¹³
• Tear gas is an aerosolized chemical irritant, not an actual gas.⁴
• CN was the dominant tear gas for many years, but CS has largely replaced it because of its performance and toxicological advantages.⁵⁶
• Scorpion Pepper Spray combines OC pepper spray with CS tear gas, reflecting the chemistry commonly used in modern riot-control agents.
• The most effective self-defense tool will always be awareness and sound judgment.

Footnotes

1. WTTW News, What Is Tear Gas, and Why Is It Used on Civilians but Banned in Combat? (Oct. 28, 2025).
2. The prohibition stems from the international framework established by the Chemical Weapons Convention, which bans riot-control agents as a method of warfare while permitting certain domestic law-enforcement uses.
3. Organisation for the Prohibition of Chemical Weapons guidance on riot-control agents and the Chemical Weapons Convention.
4. Tear gas is typically dispersed as an aerosol containing chemical irritants such as CN or CS, despite its common name.
5. Early commercial Chemical Mace® products used CN (chloroacetophenone) rather than OC pepper spray.
6. CS (2-chlorobenzalmalononitrile) became the predominant modern riot-control agent because of its effectiveness and broader adoption by law enforcement.
7. Medical reviews have noted that CS has largely supplanted CN for modern riot-control applications.