Toxicity Induced by Subchronic Dermal Exposure to Paratertiary Butyl Benzoic Acid (pt BBA) in Fischer 344 Rats

The subchronic dermal toxicity of aqueous solutions containing the diethanolamine salt of para-tertiary butyl benzoic acid was determined in Fischer 344 rats. Para-tertiary butyl benzoic acid (pt BBA) has important applications in the manufacture of resins, polymers, and corrosion inhibitors. Male and female rats were exposed topically 5 days/week for up to 13 weeks with dosing solutions that resulted in daily exposures of 0.0, 17.5, 35.0, 70.0, or 140.0 mg/kg pt BBA. These concentrations did not produce overt clinical signs of toxicity and did not cause irritation to dermal exposure sites. However, exposure to the two highest concentrations resulted in decreased weight gain. Exposure at all concentrations resulted in dosage-related increases in relative hepatic and renal weights. Exposure of males to the two highest concentrations caused decreased testis weight. Exposure-related pathologic changes were confined to three organ systems: cytoplasmic vacuolation in the liver; tubular dilation and papillary necrosis of the kidneys; and tubular degeneration in the testes. Accompanying aberations in clinical chemistry values suggested altered hepatic and renal function. In males exposed daily to 70.0 and 140.0 mg/kg pt BBA, the testicular effects were marked, but no effects were detected in rats exposed to 17.5 or 35.0 mg/kg of pt BBA.