Pivaloyl chloride

Endpoint summary

Description of key information

Pivanoyl chloride is of low systemic toxicity after dermal contact. Due to its causic properties the substance is of moderate toxicity after ingestion. Pivanoyl chloride is toxic via inhalation.

Additional information

oral:
Sprague-Dawley rats (5/sex/dose) were exposed to pivaloyl chloride via gavage at doses of 500, 650 or 800 mg/kg-bw and observed for 14 days (Stillmeadow, 1986). The number of deaths (and time of death) was as follows: 2/10 at 500 mg/kg,4/10 at 650 mg/kg and 9/10 at 800 mg/kg. Necropsy findings observed reflect the caustic propreties of the substance. The LD50was 638 mg/kg bw.

In a guideline study (OECD TG 401), Sprague-Dawley rats (5/sex/dose) were exposed to pivaloyl chloride in olive oil via gavage at doses of 316, 681, 1000, 1470, 2150, 3160 mg/kg-bw and observed for 14 days (BASF, 1981). There were no deaths or clinical signs of toxicity at 316 and 681mg/kg; there were also no deaths at 1000 mg/kg. At 1470 mg/kg, 4/10 animals died. At the two highest doses, all animals died. Animals that died during the observation period showed haemorrhage in stomach and intestines. Necropsy findings observed reflect the caustic propreties of the substance. The estimated LD50 values in males, females and combined sexes are ca. 1470, ca. 1330, and ca. 1470 mg/kg bw, respectively.

dermal:
In a study similar to OECD TG 402, white rabbits (5/sex) were exposed via the dermal route, under a semi-occlusive cover, to 2010 mg/kg-bw pivaloyl chloride for 24 hours. Animals were observed for mortality and signs of toxicity for 14 days post exposure (Stillmeadow, 1987). Gross necropsy findings in the one animal that died included extensive ulceration throughout the exposed area. The dermal LD50 value is greater than 2010 mg/kg bw.

inhalation:
In a study similar to OECD TG 403, Sprague-Dawley rats (5/sex/concentration) were exposed to pivaloyl chloride as an aerosol for one hour at 1.14, 1.47, 2.28 (males only), 2.57, 2.75 or 5.15 mg/L and observed for 14 days (Stillmeadow, 1987a). The test material was generated as an aerosol. However, the material the animals were exposed to may have been vapor indicated by the volatility of the material, lack of particles collected when particle sizing was attempted and visual inspection of the chamber. The number of deaths (and time of death) was as follows: no deaths at 1.14, 1.47 and 2.28 mg/L; at 2.57 mg/L: 3/5 males (within Day 1); at 2.75 mg/L: 4/5 males and 2/5 females; and at 5.15 mg/L all animals died. Gross necropsy findings in animals that died before study termination included signs of lacrimation, nasal discharge, discoloration of lungs. The 1-hr LC50 is 2.69 mg/L (combined sexes). According to EC/1272/2008 Annex I, 3.1.2.1.b the 4hr-LC50 is calculated for vapour by dividing by factor 2: 4h-LC50 = 1.35 mg/L.

In a guideline study (OECD TG 403), Sprague-Dawley rats (5/sex/concentration) were exposed via nose only for 4 hours to pivaloyl chloride at 0, 1.43 or 1.646 mg/L (0, 232 and 334 ppm) and observed for 14 days (Hazelton, 1988). All animals survived at 1.43 mg/L while all animals died at 1.646 mg/L. Clinical signs attributable to treatment were observed for two days post-exposure and included lacrimation, salivation, hunched posture, lethargy and respiratory distress. All animals that died had increased lung weights; gross findings included inflated lungs that were red or dark with white frothy fluid in the trachea, which is likely a sign of lung oedema. At termination, animals exposed to 1.43 mg/L had similar lung weights as controls; necropsies were unremarkable. The 4-hr LC50 was between 1.43 and 1.65 mg/L.

Justification for classification or non-classification

Based on the available data a classification concerning acute inhalation toxicity (acute inhal. Cat 2) is warranted according to regulatin 1272/2008/EC.

Oral toxicity is a secondary effect of the caustic properties of the substance, however labeled as acute oral Cat 4.

No classification suggested for acute dermal toxicity as criteria of regulation 1272/2008/EC are not met.