The industry's control and manipulation of nicotine in the production of cigarettes begins before the cured tobacco leaf reaches the manufacturing plant. The characteristics of leaf tobacco, including nicotine content, are established by the genetic makeup of the plant, developed during growing, and fixed by post-harvest handling. Like other raw agricultural commodities, the physical and chemical properties of tobacco, including nicotine, can vary widely, depending on genetic differences, growing season conditions, and soil type. Modern types of cultivated tobacco (Nicotiana tabacum L) have been selected for a relatively high level of nicotine. Five major types of tobacco make up nearly all tobacco products marketed: Burley, flue-cured, Maryland, the Dark tobaccos, and Oriental.
A class action by nine people representing a half-million sick smokers or their survivors in the US State of Florida resulted in a landmark finding (July 1999) which held America's five largest tobacco companies liable for making a defective product. The jury found that the industry had "engaged in extreme and outrageous conduct... with the intent to inflict severe emotional distress". The Florida ruling has delivered such a broad condemnation of the tobacco industry that a flurry of similar class-action claims is considered inevitable.
The development of enhanced nicotine tobacco (Y-1) dates back to at least the mid-1970's. In 1977, James F. Chaplin, who was affiliated with both USDA and North Carolina State University, indicated that tobacco could be bred to increase nicotine levels, by crossbreeding commercial varieties of tobacco with Nicotiana rustica. N. rustica is a wild tobacco variety that is very high in nicotine, but is not used in manufacturing cigarettes because of its harshness.
The tobacco industry engages in a number of agronomic practices that increase nicotine levels in tobacco. Heavy application of nitrogen fertilizers, early topping, and tight "sucker control" (i.e., bud growth at the junction of stalk and leaves) have all acted in concert to push nicotine levels upward.
Smokeless tobacco manufacturers both manipulate the amount of nicotine delivered by their products and promote the graduation of smokeless tobacco consumers from the lowest to the highest nicotine products, demonstrating an intention to facilitate nicotine dependence.