The Inhalation toxicity of di- and triethanolamine upon repeated exposure

Systemic and respiratory tract (RT) toxicity of triethanolamine (TEA) was assessed in a 28-day nose-only inhalation study in Wistar rats (10 animals/sex, concentrations: 0, 20, 100, 500 mg/m³; 5 days/week, 6 h/day). In two nose-only 90-day inhalation studies, with similar exposure design, Wistar rats were exposed to 0, 15, 150, 400 mg/m³ diethanolamine (DEA) (DEA Study 1:13 animals/sex, general subchronic study) and to 0, 1.5, 3, 8 mg/m³ (DEA Study 2:10 animals/sex) to specifically investigate respiratory tract toxicity. Only DEA induced systemic toxicity at or above 150 mg/m³ (body and organ weight changes, clinical- and histo-pathological changes indicative for mild blood, liver, kidney and testicular effects). Neurotoxicity was not observed for both substances. Exposure to both substances resulted in laryngeal epithelial changes starting from 3 mg/m³ for DEA (reversible metaplasia at the base of the epiglottis, inflammation at higher concentrations extending into the trachea) or from 20 mg/m³ for TEA (focal inflammation, starting in single male animals). TEA appears to be less potent with respect to systemic toxicity and RT irritancy than DEA. The 90-day no adverse effect concentration” (NOAEC) for changes due to TEA exposure in the respiratory tract was 4.7 mg/m³ derived by extrapolation from the NOAEC of the 28 day study.