Diammonium phosphate, or DAP, is a base form of ammonia that originally was added to cigarettes to improve smoke flavor. It is commonly used in commercial cigarettes to freebase nicotine, among other functions.
American cigarette makers, including Philip Morris (PM), have used ammonia in their manufacturing processes for decades, to "puff up" tobacco and increase its volume, highlight certain flavors, help hold together reconstituted tobacco sheet and reduce the amount of nicotine. Lesser known is that tobacco companies use ammonia to "freebase" the nicotine in smoke, essentially turning it into "crack nicotine." Freebase nicotine is absorbed by the body more quickly and easily, resulting in a faster, harder "kick" after lighting up. Using ammonia has allowed tobacco companies to lower the tar and nicotine levels in cigarettes while still keeping smokers addicted, a strategy developed to deal with the health fears surrounding cigarettes. PM was the first to use "ammonia technology," applying it to Marlboros in the 1960s. After the change, Marlboro zoomed from a minor brand to a runaway market success, causing other cigarette makers to scramble to discover PM's "secret." After PM was accused of intentionally manipulating the nicotine deliveries of its cigarettes, the company pointed to all the other uses for ammonia to defend itself against the charge.
In 1962, Philip Morris did a study that revealed that DAP-containing cigarettes delivered 0.57 mg of nicotine per cigarette versus 0.44 mg in untreated tobaccos. Since the company was aware of the increasing demand for low-nicotine cigarettes, Philip Morris later used its patented "DAP-BL" process to give its low-tar, low-nicotine Merit brand an advantage over its competitors. Merit cigarettes boasted a total nicotine yield (measured by Federal Trade Commission machines) only half of that found in Marlboros, but still managed to make available the same amount of free nicotine to smokers (about 0.33 mg in both instances).
- Terrell Stevenson, Robert N. Proctor The SECRET and SOUL of Marlboro: Phillip Morris and the Origins, Spread, and Denial of Nicotine Freebasing American Journal of Public Health, Public Health Then and Now. July 2008, Vol 98, No. 7 Pp.1184-1194