[' ', 'rates', 'were', 'evaluated', 'in', 'both', 'species', 'treated', 'with', '1,4', 'dichlorobenzene,', 'increased', 'rates', 'of', 'replicative', 'DNA', 'synthesis', 'were', 'noted', 'in', 'both', 'mice', 'and', 'rats', '(Eldridge,', '1991', ').', 'Inan', 'acute', 'inhalation', 'study', 'investigating', 'the', 'cel!', 'proliferative', 'effects', 'of', 'the', 'nasal', 'irritants', 'formaldehyde', 'and', 'acrolein,', 'both', 'formaldehyde', 'and', 'acrolein', 'demonstrated', 'an', 'increase', 'in', 'replicative', 'DNA', 'synthesis', 'response', 'acutely', 'even', 'though', 'a', 'carcinogenic', 'effect', 'after', 'chronic', 'exposure', 'is', 'only', 'seen', 'with', 'formaldehyde', '(Roemer', 'etal.,', '1993).', 'A', 'recent', 'experimental', 'study', 'has', 'reported', 'that', 'the', 'predictive', 'potential', 'of', 'increased', 'replicative', 'DNA', 'synthesis', 'in', 'terms', 'of', 'individual', 'animal', 'cancer', 'risk', 'is', 'weak.', 'In', 'a', 'mouse', 'skin', 'tumor', '‘model,', 'neither', 'increased', 'DNA', 'adduct', 'levels', 'in', 'skin', 'nor', 'increased', 'replicative', 'DNA', 'synthesis', 'were', 'predictive', 'of', 'the', 'individual', 'cancer', 'risk', 'in', 'the', 'animals', 'tested', '(Fischer', 'et', 'al.,', '1993).', 'According', 'to', 'a', 'recent', 'report', 'which', 'included', 'information', 'about', '19', 'chemicals', 'tested', 'by', 'inhalation', 'exposure', 'in', 'rodents,', 'the', 'association', 'between', 'proliferative', 'changes', 'such', 'as', 'increased', 'replicative', 'DNA', 'synthesis', 'and', 'hyperplasia', 'in', 'nasal', 'tissues', 'and', 'nasal', 'carcinogenesis', 'is', 'weak.', 'Of', 'the', '19', 'compounds', 'tested,', '5', 'were', 'reported', 'to', 'be', 'nasal', 'carcinogens', 'in', 'the', 'rodent.', 'All', '5', 'of', 'the', 'rodent', 'nasal', 'carcinogens', 'displayed', 'proliferative', 'changes', 'in', 'the', 'nose.', 'Of', 'the', '14', 'compounds', 'tested', 'which', 'were', 'not', 'reported', 'to', 'be', 'nasal', 'carcinogens,', '12', 'of', 'the', '14', 'demonstrated', 'similar', 'proliferative', 'changes', 'in', 'the', 'nose', 'as', 'did', 'the', 'nasal', 'carcinogens,', 'suggesting', 'that', 'proliferative', 'changes', 'alone', 'are', 'not', 'predictors', 'of', 'nasal', 'carcinogenesis', '(Ward', 'et', 'al.,', '1993).', 'These', 'data', 'cannot', 'be', 'used', 'to', 'support', 'the', 'hypothesis', 'that', 'ADSS', 'is', 'a', 'potential', 'nasal', 'carcinogen', 'in', 'the', 'rat.', 'In', 'this', 'study,', 'lack', 'of', 'statistically', 'significant', 'findings', 'at', 'the', 'end', 'of', 'the', 'recovery', 'period', 'after', 'a', '13', 'week', 'period', 'without', 'smoke', 'exposure', 'indicates', 'that', 'the', 'effects', 'observed', 'at', 'the', 'end', 'of', '90', 'days', 'were', 'not', 'sustained', 'after', 'cessation', 'of', 'exposure.', 'The', 'diminution', 'of', 'effects', 'over', 'the', 'course', 'of', 'the', '13', 'week', 'exposure', 'period', 'indicates', 'that', 'the', 'animals', 'adapted', 'to', 'the', 'potential', 'effects', 'of', 'ADSS', 'exposure.', 'The', 'statistically', 'significant', 'findings', 'in', 'the', 'nasal', '"section', '1"', 'coincide', 'with', 'the', 'histopathological', 'effects', 'noted', 'in', 'the', 'nasal', '“section', '1"', 'reported', 'earlier', '(Coggins', 'et', 'al.,', '1993).', 'In', 'general,', 'statistically', 'significant', 'findings', 'were', 'noted', 'only', 'in', 'nasal', 'tissues', 'of', 'the', 'rat', 'after', 'subchronic', 'exposure', 'to', 'the', ' ', 'SELB', 'SSSTS', ' ']