Philip Morris and other tobacco companies have been using ammonia in their manufacturing for more than half a century, and for a variety of purposes: to highlight certain flavors, to expand or “puff up” the volume of tobacco, to prepare reconstituted tobacco sheet (“recon”), to denicotinize (reduce the amount of nicotine in) tobacco, and to make the cigarettes more addictive by delivering nicotine to the brain more quickly.

Marlboro’s commercial success catalyzed efforts by the rest of the tobacco industry to discover its “secret,” eventually identified as ammonia technology. Philip Morris, the company that owns Marlboro brand, later exploited the myriad uses of ammonia (e.g., for flavoring and expanding tobacco volume) to defend itself against charges of manipulating the nicotine deliveries of its cigarettes.

Starting in the 1950s, tobacco companies were looking for ways to make their products more addictive and appealing to consumers. One of the methods they explored was to add chemicals to cigarettes that would enhance the effects of nicotine and make it more rapidly absorbed into the bloodstream.

By the early 1960s, Philip Morris scientists had discovered that ammonia could also be used to increase the free nicotine in cigarette smoke, providing a more powerful nicotine kick than the milder low-pH tobaccos traditionally used in American-blend cigarettes.

One such chemical was ammonia, which is commonly used in the production of freebase cocaine. Freebasing is a method of smoking drugs that involves heating a substance, typically a base form of a drug such as cocaine, to a high temperature and inhaling the resulting vapors.

Ammonia increases the alkalinity of nicotine, allowing it to be more easily absorbed into the lungs and brain. Tobacco companies began adding ammonia to their cigarettes in the form of ammonium hydroxide, which helped to create a more potent and addictive product.

In addition, tobacco companies also experimented with adding other chemicals to cigarettes to enhance their effects, such as acetaldehyde, which is a byproduct of the combustion of ethanol. This chemical has been shown to increase the addictive properties of nicotine by stimulating the release of dopamine in the brain.

The tobacco companies’ use of ammonia and other chemicals in cigarettes helped to popularize freebasing by making it easier for smokers to achieve a more intense and addictive high. This has had devastating consequences for public health, as smoking remains one of the leading causes of preventable death worldwide.