- 22 Page 11, lines 15-17 - "For all of these reasons it is proposed that inhaled insoluble alpha emitting amoke particles are very Likely to be the mutagenic agent which gives rise to atherosclerosis in cigarette smokers." Comments: This statement is a string of poorly founded presumptions covered by previous comments. Page 11, lines 18-21 - "If this is the case, similar increased risk of early coronaries are to be expected for other groups of individuals who are occupationally or environmentally exposed to the inhalation of insoluble alpha emitting particles of respirable size," Comments: "Tf. this is the case" is a poorly founded presumption, for reasons covered in previous comments, Page 11, lines 26 to Page 12, line 2 - "Very significant increases in the incidence of early coronaries as well as lung cancers and cancers at other sites is observed among cigarette smokers‘*6) with insoluble alpha emitting particle burdens of only a few picocuries of 210p5 in the lung 14) and similar total alpha activity per 100 grams of arterial wall tissue(41-43) .» Comments: This sentence is misleading in tying the alpha activity of arterial wall tissue to the statement about incidence of diseases among cigarette smokers. The references (41-43) refer to Elkeles' papers reporting alpha particle activity in calcified atherosclerosis and in coronary artery disease, based on measurements in plaques and vessels, where it is most likely that calcium, and alpha radioactivity with it, increase after alterations of the arterial tissue that lead to the rest of the atherosclerotic mechanisms have occurred (see comments on page Ll, lines 3-7 and 10-12). Page 12, line 3 to Page 13, line 2 - "By comparison, plutonium workers exhibit plutonium organ burdens ranging from a few picocuries to a few