['composition', 'was', 'similar', 'to', 'the', 'University', 'of', 'Kentucky', 'Reference', '[R4F', 'cigarette.', 'There', 'were', 'no', 'quantitative', 'differences.', 'in', 'the', 'concentration', 'off', 'gas', 'phase', 'CD,', 'NO,', 'HCN,', 'and', 'RCHO', 'of', 'urea-treated', 'cigarettes', 'compared', 'with', 'controls.', 'Organic', 'gas', 'phase', 'analysis', 'using', 'nitrogen-phosphorus', 'detection', '(NPD)', 'and', 'flame', 'ionization:', 'detection', '(FID)', 'resulted', 'in', 'no:', 'major', 'qualitative', 'differences', 'between', '2%', 'urea-treated', 'cigarettes', 'compared', 'with', 'controls.', 'There', 'were', 'no', 'peaks:', 'present', 'in', 'the', 'gas', 'phase', 'of', 'urea-treated', 'cigarettes', 'that', 'were', 'not', 'also', 'present.', 'in', 'the', 'gas.', 'phase', 'of', 'the', 'control', 'cigarettes.', 'However,', 'both', 'the', 'NPO', 'and', 'FID', 'data,', 'indicated', 'a', '10%', 'to', '20%', 'reductions', '“inthe:', 'levells', 'of', 'gas:', 'phase', 'components', 'for', 'the', 'urea-treated', 'cigarettes.', 'In', 'a.', 'similar', 'study', 'of', 'cigarettes', 'containing', 'flue-cured', 'tobacco', 'treated', 'with', '2%', 'urea,', 'it', 'was', 'found', 'that', 'the', 'smoke', 'from', 'urea-treated', 'cigarettes', 'had', 'levels', 'of', 'HCN', 'and', 'NO', 'that', 'were', 'not', 'different', 'from', 'those', 'of', 'the', 'control', 'cigarettes', '(Norman,', '1983).', 'In', 'a', 'corroborating', 'study', 'from', 'the', 'patient', 'literature,', 'it', 'was', 'found', 'that,', 'when:', 'added!', 'to', 'tobacco,', 'urea', 'reduces', 'the', 'amount', 'of', 'certain.', 'pyrolysis', 'products', 'in', 'smoke:', '‘43%', 'decrease:', 'iin', 'benzo[a]pyrene;', '15%', 'decrease', 'ini', 'CO;', 'and', '20%', 'decrease', 'in', 'crude', 'condensate.', 'In', 'addition,', 'the', 'study', 'indicated', 'that', 'urea', 'impedes', 'the', 'formation', 'of', 'N-nitrosamines', '(T.K.R.', 'Oritte', 'Tabac,', '1981).', '<024003089']