Attorney General Bill Barr has defended the use of pepper spray against protesters in Washington DC last Monday, claiming that the substance is “not a chemical irritant.”

The claim that substances found in ‘natural’ sources are not made of chemicals is patently incorrect. Pretty much everything around us is made of chemicals, an apple, for example naturally has around 300 different chemicals in it. These include formaldehyde and cyanide which are well-known to be harmful to humans in quantities far larger than found in an apple.

The Cambridge English dictionary defines a ‘chemical’ as “any basic substance that is used in or produced by a reaction involving changes to atoms or molecules” and ‘chemistry’ as; “the scientific study of the basic characteristics of substances and the ways in which they react or combine.”

A number of chemists on twitter were quick to respond with reasoned debunking of why AG Barr’s comments were incorrect.

The main ingredient of pepper spray is oleoresin capsicum, which is a chemical also found in hot peppers and chilis and is responsible the hot, burning sensation experienced when eating them. But pepper spray contains massive, concentrated quantities of capsicum, making it far ‘hotter’ and more potent than even the most infamous chilis as discussed in this excellent Scientific American article from 2011.

Pepper spray isn’t just chili juice in a can, it is a concentrated chemical weapon which causes intense, temporary pain for some, but potentially permanent damage in others. It has even been linked to some fatalities and one pepper spray company even advertises its product as “the most effective chemical irritant available.”

So, AG Barr is entirely incorrect by saying that pepper spray has no chemicals in it, when it in fact comprises entirely of them. But the language used is an example of how the term ‘chemical’ is often presumed to be bad and relate to artificial substances and in contrast, naturally-derived products are assumed to be less harmful. By saying that no chemicals were present in the pepper spray, Barr was almost certainly trying to suggest that the substance used was less harmful than it actually was.

Such an assumption is at the very core of some aspects of ‘alternative’ medicine where purveyors claim that natural remedies are less harmful than those synthesized artificially, where often the opposite of this often can be true. A good example from the world of alternative cancer therapies is apricot kernels, yes – the husky, hard bit at the center of an apricot. There is no evidence that these are effective for the treatment or prevention of any type of cancer whatsoever. Not only that, apricot kernels naturally have shockingly high levels of cyanide and some people with cancer have given themselves cyanide poisoning from eating the kernels or oils made from them.

Pretty much everything is comprised of chemicals, food, animals, plants and yes – pepper spray. As to whether chemicals are harmful or beneficial to health depends on several things including where in the body the chemical goes, how much of it is present and even how it interacts with other chemicals. For example, many of us enjoy eating hot peppers as part of food, but do not enjoy the experience of accidentally rubbing our eyes after preparing said hot peppers.

Although they share some of the same core ingredients, Barr wasn’t talking about hot peppers. He was talking about a chemical weapon attempting to downplay its harm to protesters by capitalizing on the widely-believed misunderstanding that naturally derived substances are not harmful.