This information must be predicated with the explanation that any use of tear gas can cause problems, and if deployed to the point of over-saturation can be harmful and in extreme circumstances be potentially lethal. This would require the gas to be deployed in extreme quantities in an enclosed environment with little to no air circulation over a time period long enough to have such an effect. Normal deployment of tear gas elements, especially in an outdoor environment, or even indoors in proper amounts creates no such threats to human or animals.
The chemicals are designed to affect the lachrymal system and as such the lachrymal system of the canine species is significantly different than that of a human being. The chemicals also cause a strong burning sensation to the skin, particularly in areas of high sweat such as the forehead, arm pits and groin in human beings. The various combinations of discomfort make the use of tear gas products very effect in controlling crowds.
Keep in mind that lachrymators (chemical munitions or tear gas such as CS and OC) can cause irritation for dogs and other animals, however each species is affected at a different rate.
Here is why police dogs are able to work through CS, CN and OC conditions. Please understand that this information was provided to me by Dr. John Anderson, who was a veterinarian on my staff and was often present when we trained dogs in tear gas environments. Over the years I have worked in CS, CN and OC environments and have deployed well over a thousand teams, if not thousands of teams in these environments. CN was used in the early years, but was quickly replaced by CS gas, and is no longer used as CN was more toxic, and less effective than CS gas, so CN is no longer used. Dr. Anderson was killed in a farming accident a number of years back, and sadly we lost a good man and one of the best authorities on this subject. It appears that we are one of the only organizations in the world that have this level of experience of deploying dogs in tear gas environments simply because of the volume of officers and dogs we have trained.
1. The lachrymal system of the dog is much more efficient than that of a human being. In my early years, I was taught that dogs do not have tear ducts, or a lachrymal system. In fact even today on Wikipedia when you look up CS Gas, you will find a line that reads, “CS has less effect on animals due to "under-developed tear-ducts”. In fact the canine species lachrymal system is much more efficient at flushing the eye than human beings. The excretory ducts for larger dogs are significantly larger in diameter. The lachrymal ducts themselves are also significantly larger in the canine species than in humans. For comparison the average size of the lachrymal gland in a human being is 20mm x 12mm, whereas in the canine species the size of the lachrymal glad averages 152mm x 138mm. This allows for significantly more efficiency for flushing the eye of irritants by the canine species. By volume alone the lachrymal system in a large adult dog is close to 87 times greater than that of a human being. Dr. Anderson taught me that the dogs eyes can flush at rates at least 10 times more efficiently than a human being, however as I have learned more, I believe that it is even more efficient than what Dr. Anderson believed at that time.
2. During a few indoor deployments of the dogs in a heavy gas environment where I was acting as the decoy (the subject who the dogs would have to search for using their olfactory capabilities and then bite a protective sleeve during training), on a few occasions when the gas was particularly heavy after initial deployment of the gas, I have observed the nictitating membrane drawing over the eye of the dog. This acts as a secondary protection for the dog should the lacrimal system not be able to flush the eyes quickly enough to overcome the irritant effects of the tear gas.
3. The canine species does not have an Apocrine system development like we do. Their bodies are covered in fur and they do not have sweat glands that excrete fluid other than around the nose and on the paw pads. Therefore, there is very limited areas of the dog’s body that would be affected in the manner than it would affect a person. The dog simply would not feel the burning sensation on the skin, or in the groin as a human being would.
4. In reality, CS gas is actually not a gas but a very fine acidic powder with acidic PH values. The acidic powder is made into a solution which is then sprayed as an aerosol or released by grenades through burning. The skin on human beings by nature is acidic, and therefore when hit with product of acidic value are susceptible to the resulting burning sensation. The body of the canine species however has a PH value of 7.5, which is slightly alkali. Therefore, the natural chemical makeup of the dog naturally reduces the irritant effectiveness, providing further protection to the dog.
Pets would likely not be as resistant to the irritant, and although they would not feel much in the way of discomfort, they would certainly be able to feel the effects of the product. However police and other working dogs are normally bred and raised and have a genetic propensity for courage, and strength with a high threshold for tolerance, and as such rarely if ever exhibit any issues when working in even higher levels of CS or OC environments. Pepper spray, (OC) is often sold as a dog or even a bear spray deterrent, and is quite effective on most dogs and animals as it is designed to be sprayed directly into the face of the attacking animal, is normally of higher concentration and creates a fast and instant burn that the animal doesn’t understand and therefore gets confused, thus defeating the attack in most cases.
However, we have also demonstrated during one of our conferences how those products can be sprayed directly above the eyes, literally soaking the dogs forehead with product while he was on the bite of a decoy and fighting the man, and even though there was copious amounts of OC on the dogs face, the dog never gave up the fight. We have then immediately within seconds of calling the dog off the bite, sent that dog to search and attempt to located a second suspect that the dog needed to track using his olfactory capabilities, and have observed the dog have no problem in search out the second suspect and apprehending him.
This is not something we do on a regular basis, but was a test done while our vet team was in attendance with care to ensure the dog was not sprayed directly in the eyes as that would injure the dogs eyes from the stream of the product. There was no ill effect and it was apparent the dog had been over-saturated, but he was still able to work through the exercise.
More than the CS/OC environment the visual effect of Smoke on the dogs seems to be more of an issue. The dogs have a tendency to hesitate when they see the smoke. In some cases the dogs will stop and resist moving into the smoke if it is thick, as it seems to appear to be a wall to some of the dogs. Other dogs have no issues, and it appears to be a perception issue with some of them.
VERY IMPORTANT: Smoke (HC) from smoke grenades (HC) not the smoke from CS canisters, but smoke used for smoke screens) is made from a product that quite toxic and carcinogenic. It also displaces oxygen,
and in an enclosed environment can cause problems with the dogs. Smoke canisters that are deployed to provide a screen for police entry teams are rarely if ever used, but they will reduce oxygen levels in an enclosed area very rapidly. Therefore when we train dogs to be able to over come the visual effects of the smoke emitted from CS canisters, we use theatrical smoke machines for that training, or the actual CS gas canisters so we do not unnecessarily put the officers or dogs at risk using HC Smoke products unless we are in an open well ventilated area and the exposure is very limited.
I have trained thousands of dogs around the world and have put well over a thousand dogs through CS and OC environments during training I have conducted with police and military forces. I have personally worked many dogs inside building and rooms filled with CS or OC gas. When properly deployed, police dogs suffer no ill effects from working in the gas and in fact are fully functional and able to use their olfactory capabilities to actively search and locate hidden suspects who are hiding in a tear gas environment.
One interesting side note. I have learned that over time and with regular training in a gas environment a person can begin to build up an immunity to the effects of the gas. I have found that it doesn’t affect me as strongly as it did when I first trained in that environment, and I suspect the same occurs with dogs that are regularly trained in a CS or OC environment. It by no means makes me immune, but I find that the burn isn’t as intense and I am able to work longer in the environment without much discomfort. In one of my more recent training conferences, I worked for close to four hours in an enclosed environment filled with CS gas with very few breaks, taking bites from 60 dogs during that period of time, and I was quite comfortable. There would be no way I would have been able to do that when I first began my training many years ago.
Police dogs are fully capable of locating and apprehending suspects in a tear gas environment.