Ongoing studies of the physiological effects of carbon-black (1333864) on laboratory animals are described. Carbon-black samples obtained from oil or gas furnaces were administered to mice, hamsters, guinea-pigs, rabbits or monkeys. The oil furnace samples originated from combustion of petroleum residues and aromatic oils and contained 0.053 to 0.374 percent benzene extractable adsorbed components. The gas samples contained 0.118 to 1.04 percent benzene extractable components. Routes of administration involved subcutaneous and intraperitoneal injection, ingestion, inhalation, and skin applications utilizing water or mineral or vegetable oils as the suspending vehicles. Monkeys or mice were exposed to 1.5 milligrams per cubic feet carbon-black by inhalation for 9 years. To date, no detectable, harmful, or significant gross or histological abnormalities were observed in any organ or tissue of any of the species. Current experiments in which mice were being fed the benzene extract of an oil furnace carbon-black, methylcholanthrene (56495), or methylcholanthrene adsorbing on the carbon-black are described. Experiments in which a monkey, mice, and guinea-pigs were exposed to 2.1 milligrams/cubic feet of a carbon-black extract are also described.
Report (Unpublished) Submitted to NIOSH by the Environmental Health Association of the Carbon Black Industry, Inc., Borger, Texas, 14 pages