title: 4-Phenylcyclohexene: 2-week inhalation toxicity and neurotoxicity studies in Swiss-Webster mice.
abstract: 4-Phenylcyclohexene (4-PCH) is a by-product formed during the polymerization of styrene-butadiene latex used in carpet backing. Limited reports suggest that exposure to very low levels of 4-PCH or other emission products following new carpet installation may result in health complaints. Significantly, it has been claimed that Swiss-Webster mice held in neck restraints and exposed head-only to approximately 0.4 ppm 4-PCH for a few hours suffered severe toxicity including death. A 2-wk inhalation and neurotoxicity study was therefore conducted in Swiss-Webster mice using standard methods of toxicity testing. Groups of 40 mice were exposed to 0, 7, 18 or 71 ppm (near-saturated atmosphere) 4-PCH vapour, 6 hr/day for 9 consecutive days. Data were collected on a wide variety of clinical, neurological and histopathological parameters including extensive neurohistopathology. All animals survived the exposures, and there were no treatment-related effects. Because of the occurrence of spontaneous lesions in two high-dose group mice, 40 additional males were exposed to 0 ppm or a near-saturated atmosphere of 4-PCH under the same exposure regimen. No treatment-related lesions were observed in the follow-up study, confirming the conclusions of the original study. These findings, consistent with the reported lack of toxicity of inhaled 4-PCH in rats, do not suggest a direct, organic, association between low-level 4-PCH exposure and human complaints. Further, the results of this study suggest that positive findings in mice may have been due to methodological problems and not to exposure to 4-PCH.
authors.affiliation: Toxicology Research Laboratory, Dow Chemical Company, Midland, MI 48674, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Beekman
authors.forename: J P
authors.initials: JP
authors.lastname: Maurissen
authors.forename: K A
authors.initials: KA
authors.lastname: Johnson
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D001835:Body Weight; D001921:Brain / Q000473:pathology; D003510:Cyclohexanes / Q000008:administration & dosage / Q000633:toxicity*; D005260:Female; D005430:Floors and Floorcoverings; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000187:drug effects; D009422:Nervous System Diseases / Q000139:chemically induced* / Q000473:pathology; D009929:Organ Size / Q000187:drug effects; D013116:Spinal Cord / Q000473:pathology; D014617:Vacuoles / Q000473:pathology
chemical_list: D003510:Cyclohexanes; C080904:4-phenylcyclohexene