Acute toxicity and primary irritation of para-tertiary butylphenol

Para-tertiary butylphenol [(PTBP); the Union Carbide Corporation trademark for this chemical is UCAR Butylphenol 4-T Flake] has applications as a raw material in the manufacture of resins and also as an industrial intermediate. Acute peroral LD50 values (95% confidence limits) of 5.4 (3.6-7.9) g/kg and 3.6 (3.0-4.4) g/kg were obtained for male and female albino rats, respectively. Occluded cutaneous applications of moistened PTBP at 16 g/kg for 24 hr produced no mortalities in male or female rabbits, but signs of local toxicity and irritation were apparent at the site of application. A 6 hr exposure to a substantially saturated vapor under static conditions produced no mortality, while a 4 hr exposure to a dynamically generated respirable dust aerosol at a concentration of 5.6 mg/L produced 20% mortality. Occluded dermal contact (4 hr) with 0.5 g moistened PTBP produced a range of effects from no reaction to necrosis. PTBP placed in the conjunctival sac of rabbits produced severe ocular injury which generally persisted for 21 days after exposure. The major hazard associated with acute exposure to PTBP appears to be the irritation produced by dermal or ocular contact.