OC (oleoresin capsicum) is a derivative of hot peppers. Be careful of false advertising. Some claim 1-2 million SHU's (scoville heat units). That is total BS almost all have 50-55,000 SHU's. The 1-2 million number comes from the base product. 2 million SHU base product in a 5% mixture is still 50,000 in the can. The real difference is the carrier. Oil based carriers tend to stick and stay stuck. Very hard to decontaminate. Water based carriers tend to soak in and work faster but are easier to decontaminate. Most LE agencies choose water based carriers because we need fast acting results and we must be concerned with decontamination. Some use harmful chemicals, non food grade OC and flammable propellants. I know you do not care if the perp gets harmful chemicals in the eyes but it will be in the air and you, too, will be exposed to it.
OC works faster than CN or CS gas. If you are being attacked you want it to work NOW not 1-2 minutes from now.