From Halopedia, the Halo wiki
Tobacco is a human agricultural product processed from the leaves of plants in the genus Nicotiana. Tobacco remains an important commercial commodity in the 26th century and is commercially available in dried, cured, and natural forms. Its most common usage is for smoking in the form of cigars, cigarrettes, and pipes. Tobacco gum, a chewing substance used as an alternative to smoked tobacco, is also commonplace.
With cancer and other health issues easy to treat in the 26th century, tobacco has been rendered less threatening.
A cigar is a tightly-rolled bundle of dried and fermented tobacco which is ignited so that its smoke may be drawn into the smoker's mouth. In the 26th century, the Sweet William cigar is a luxury brand popular among humans. They are especially enjoyed by numerous members of the UNSC, like Avery Johnson.
Cigarettes are another tobacco product. Like cigars, humans have smoked cigarettes for centuries.
26th century cigarettes are protected from moisture damage by waterproof seals. Some cigarettes have "ignition ends" which light the cigarette by tapping its end, thus eliminating the need for external flammable implements; these cigarettes are popular among the Orbital Drop Shock Troopers. Cigarettes requiring traditional means of ignition are also available. The UNSC issues cigarette consumption ordinances.
Tobacco gum is a type of a chewing substance that is commonly used as an alternative to cigarettes. It is considered contraband within the UNSC. Nonetheless, tobacco gum is popular among UNSC aviators. The substance may be similar in concept to chewing tobacco.
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