In 2020 lawmakers in California and Massachusetts banned menthol, a chemical that causes a cooling sensation, as an additive in cigarettes. The idea was partly to help curb youth smoking; menthol makes cigarettes more palatable. Regulators called the chemical unsafe for its role in promoting nicotine addiction.
Soon after, we learned in detail how the tobacco industry circumvented these laws by substituting menthol with other cooling chemicals in their new “nonmenthol” cigarettes. This is the oldest trick in the book for dealing with chemicals deemed hazardous or otherwise problematic: stop using the original molecule and either find or make a substitute with the same function but with scant or nonexistent safety data. This approach allows a company to continue to produce chemicals of concern while U.S. agencies such as the Food and Drug Administration or the Environmental Protection Agency grind away to catch up to these new alternatives.
Although these new products may be legal, the original concerns remain. In this case, R.J. Reynolds simply switched out menthol for an odorless, structurally similar synthetic agent known as WS-3. Like menthol, it reduces the harshness of cigarette smoke by producing a cooling effect.
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That the tobacco industry can readily make this kind of shift speaks to a fatal flaw in how we regulate chemicals in this country. We do so not according to the concern about or the intended effect of a compound or based on what we know about related compounds. Instead we assess chemical by chemical, final product by final product. The status quo means regulators are constantly chasing tiny tweaks and clever substitutions instead of regulating classes or, better, the properties that make molecules problematic.
This game of whack-a-mole plays out with all kinds of products, not just cigarettes. Take, for example, bisphenol A (BPA), a plastics precursor and endocrine disrupter that interferes with the normal production and work of the body’s hormones. As BPA became increasingly regulated by countries around the world, it was replaced with bisphenol S (BPS), which has a molecular structure only slightly modified from that of BPA. BPS helped manufacturers achieve the goal of removing BPA from commercial products, but it causes the same endocrine problems. By banning BPA, we removed the chemical but not the concern.
Why has this obvious flaw been allowed to persist? First, it isn’t recognized as a flaw. There is a prevailing perspective in the U.S. that chemicals have rights, so to speak. When we move to regulate a chemical, we are putting that compound “on trial.” The evidence against its use generally needs to meet a certain standard of peer review, and the process needs to include public review and comment. Sadly, in the U.S., the chemical regulatory system moves more slowly than the judicial system. Regulatory action has taken many years even for substances that are well known to be hazardous, such as dichloromethane, chloroform and trichloroethylene.
But the pace of the legally required review of the science and costs is not the most significant impediment to more responsive regulation. The biggest problem is that we focus on the chemical and not the concerns people have about it, such as its toxicity or addictive properties. For regulators, a substance’s ability to cause harm should be based on the combination of its inherent physical and chemical properties. Its real-world potential to make people sick or change the atmosphere has nothing to do with the name humans have given it, and yet that is how we regulate—one discrete chemical at a time.
Regulation of chemicals does not have to be this slow, laborious, costly and ineffective. Changing this regulatory framework could benefit the chemical industry by incentivizing sustainable innovation while more effectively protecting public health and the environment. Using our understanding of how physical and chemical properties relate to different concerns gives us a new way to protect human health—by regulating the concern and not the chemical. We could define groups of chemicals as safe or troublesome based on similar physical and chemical properties, which would allow us to focus on what might create a risk or affect the function of the chemical rather than looking at its structure alone.
This approach is based on intrinsic molecular properties that contribute to both hazards and functions of different substances. Regulators could use this insight when a new chemical was proposed for commercial use. Innovative companies could benefit by using this knowledge to design molecules or invent substances that are more likely to be safe. This approach would also create greater regulatory certainty, reducing a company’s risk in bringing a chemical to market or putting one in its product that might eventually be banned.
For cigarette coolants, this would mean banning any chemical, regardless of structure, that activates the body’s receptor for menthol, named TRPM8. This receptor is located on sensory neurons that enable us to feel cool temperatures and is also activated by coolants such as WS-3 found in the new nonmenthol cigarettes. Menthol cigarettes have already been banned in the European Union, Canada, and other countries. Some nations, such as Germany and Belgium, have also banned diverse TRPM8 activators. Interestingly, the Belgian approach specifically restricts any additives to tobacco products that “facilitate nicotine inhalation or intake,” including “all components and mixtures with cooling and/or analgesic effects.” This is essentially a property-based approach. California has recently done something similar.
A property-based approach can be used to help define safer chemical properties and provide regulatory confidence, as well as to outline hazardous-chemical spaces in which chemicals with certain properties known to be associated with hazards would come under greater scrutiny. Fortunately, leading companies across many industrial sectors—from cosmetics to electronics—are beginning to think and design in this way.
If we want a chemical world that is truly safe and sustainable by design, we should match our regulatory framework to our intentions. That is, rather than banning individual molecules, which forces us to chase each new molecule of concern for decades with new regulation, we should aim to ban the central concern defined by a set of physical chemical properties. This change would lead to chemicals that are safe for people and the planet based on their intrinsic properties. Had we taken this approach from the outset, we could have protected vulnerable people from additives that make cigarettes more appealing and pleasant rather than seeing those hopes go up in smoke.
This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.