2-hydroxy-2-methylpropionitrile

Endpoint summary

Description of key information

Experimental studies on irritation / corrosion are lacking. Exposure related observations in humans as well as effects seen in an acute dermal toxicity study in rabbits and repeated dose inhalation toxicity studies in rats indicate an irritating activity of 2-hydroxy-2-methylpropanenitrile.
Due to the very high acute toxicity, irritation / corrosion testing is not applicable.
The very high dermal toxicity is reflected in the legally binding harmonised classification as given in REGULATION (EC) No 1272/2008 Annex VI Table 3.1 (GHS): Acute tox. 1; H310 and Table 3.2 (Annex I of Directive 67/548/EEC): T+; R26/27/28.

Additional information

Experimental studies on irritation / corrosion are lacking.

Exposure related observations in humans as well as effects seen in an acute dermal toxicity study in rabbits and repeated dose inhalation toxicity studies in rats indicate an irritating activity of 2-hydroxy-2-methylpropanenitrile: In the key study on acute dermal toxicity (Carreon et al., 1981, see chapter 7.2.3), slight (4/5 animals) to moderate (1/5 animals) redness, slight swelling in 3/5 animals, and slight necrosis in 1/5 animals were found after 24 hours post treatment in the surviving rabbits dosed with 6 or 25 mg/kg bw. The dose of 25 mg/kg bw was already lethal in 3/4 animals. In a subacute inhalation study (see chapter 7.5)observations during exposure to nominal 30 or 60 ppm included irritation of the eyes and/or nose and breathing difficulties. However, comparable observations at the same exposure levels in the subsequent subchronic inhalation study (see chapter 7.5) were not considered to be treatment-related by the authors since they occurred with a similar incidence in the control group or only at single times in individual animals, and were not related to concentration. Concentrations slightly overrun 60 ppm are already acute lethal (see chapter 7.2). Some information on fatalities and life-threatening occupational intoxication after accidental inhalation, skin contact and ingestion are summarised in AEGL (rationale for AEGL (Acute Exposure Guideline Levels) established by the AEGL-COMMITTEE (US-NAC, Acetone Cyanohydrin, Interim Acute Exposure Guideline Levels (AEGLs), Interim final draft, 2005): “Initial symptoms following mild exposure to acetone cyanohydrin were … nose, eye, throat and skin irritation.”

Due to the very high acute toxicity, in vivo irritation / corrosion testing is not applicable. The amount of test material required in a standard skin or eye irritation study (500 and 100 mg/animal, respectively) is considerably above the level of systemic toxicity. The very high dermal toxicity is reflected in the legally binding harmonised classification as given in REGULATION (EC) No 1272/2008 Annex VI Table 3.1 (GHS): Acute tox. 1; H310 and Table 3.2 (Annex I of Directive 67/548/EEC): T+; R26/27/28.

Justification for classification or non-classification

Experimental data on irritation / corrosion are lacking. 2 -Hydroxy-2 -methylpropanenitrile is classified as very toxic by dermal contact (legally binding harmonised classification as given in REGULATION (EC) No 1272/2008 Annex VI Table 3.1 (GHS): Acute tox. 1; H310 and Table 3.2 (Annex I of Directive 67/548/EEC): T+; R26/27/28). Therefore, in compliance with REGULATION (EC) No 1907/2006 Annex VII 8.1 Column 2, irritation/corrosion testing is not indicated.

Classification for irritation is not possible.