566 



constituents in tobacco smoke and development of technology to attempt to reduce or 

 remove those of potential concern, and (ii) development of new technologies to reduce 

 yields of "tar" and nicotine generally. The first line of research has had limited success; the 

 second line of research has been remarkably successful. 



Selective Reduction 



During the 1950s and early 1960s, many researchers focused on one chemical 

 constituent of smoke (or a family of constituents) in the search for a "cancer-causing" agent 

 that would explain the epidemiologic and skin painting results. This focus turned to 

 disappointment, as reflected in the 1964 Report of the Advisory Committee to the Surgeon 

 General ("Surgeon General's Report"). From the mid-1950s until today, a succession of 

 constituents has been targeted by the biomedical community. Even today, however, the 

 biomedical community has been unable to agree on which, if any, of those constituents is 

 responsible for the reported association between cigarette smoking and lung cancer. 



Cigarette manufacturers and others explored and published numerous methods to 

 reduce or eliminate individual constituents (or a family of constituents) in cigarette smoke, 

 e.g.. reducing the temperature at which the cigarettes burned, breeding tobacco plants to 

 change the chemical composition of the tobacco, and adding different types of filters or 

 other filtration mechanisms to the cigarette. Unfortunately, manufacturers faced a moving 

 target as the focus changed from constituent to constituent. Constituents of concern at one 

 point in time were later determined by the scientific community to be of no significance. 

 Moreover, techniques that might have selectively reduced a constituent in the laboratory 



-5- 



