In our jail (which holds up to 600+) we always used OC, a lot of OC indoors. We would never use CS in any indoor area in the Jail. If you use CS in a confined area such as in the jail you will be spending a lot of time and effort cleaning it up. We were also taught as Instructors in this area of chemical munitions as to use what Chemical would be used and we would therefore compute the dosage of chemical munition in this kind of situation and where to fire it. The reason being is that if you do use CS you will own that structure until you have decontaminated that structure whether it be a home, office building, an abandoned building, and so on and so forth.
CN has a faster reaction time compared to CS. CS has a longer effect on people then CN does. And OC, depending on the strength, will cause immediate burns with the possibility of causing First and secondary Chemical burns. This why many, many years ago they mixed CN with DM. The DM took longer to reach its peak limit. The CN took over the for the first effect quickly enough so that the DM could do it's thing. According to some sources within the government is that it no longer can be produced and used. If you get enough of CS, CN, and even OC into your system you could possibly die from the effects. This is very true when it comes to people who have asthma and other Pulmonary problems.
I have never seen our department use CN ever. Not when you had OC or CS with you., which we did.