3-methyl-2-butenal

Endpoint summary

Justification for classification or non-classification

Acute oral toxicity:

BASF (1979) reported an oral LD50 value of 690 mg/kg for male and female rats. The test substance was given in doses of 316, 464, 562, 681, 825 and 1000 mg/kg. Clinical signs observed were dyspnoea, gasping, apathy, abnormal lateral position, staggering, tremor, muscle-twitching, spastic movement, saltation convulsions, trismus, tonic convulsions, scrubby coat, erythema, cyanosis, salivation, lacrimation, disturbance of equilibrium and a poor general state. Mortalities were observed at doses higher than 563 mg/kg; all animals died in the highest dose group (1000 mg/kg). This test was done equivalent or similar to OECD guideline 401.

In an older BASF study (1971) the oral LD50 value was found to be 810 mg/kg for male and female rats. The test substance was given in doses of 0.4, 0.8, 1.0, 1.25, 3.2 and 6.4 ml/kg (= 352, 704, 880, 1100, 2816 and 5632 mg/kg). Clinical signs observed were convulsions, dsypnoea, atonia and abdominal position. All male and female animals died in the two highest dose groups within 24 hours; at 1.25 ml/kg most of the males and all females died within 24 hours. This test was done with BASF-internal standards.

Classification proposal for acute oral toxicity according to Annex I of the EU Directive 67/548/EEC with R 22 (harmful if swallowed).

Acute inhalation toxicity:

An inhalative LC50 value of 3.7 mg/l/4 h was found for male and female rats (BASF, 1979). Rats were given concentrations of 0.97, 3.15, 3.59, 3.88 and 6.08 mg/l. Animals from the 2 lowest dose groups recovered within 5 days from signs which included lacrimation and nasal discharges, closed lids, labored breathing, unkept fur. Signs were more pronounced in animals receiving higher doses and included dyspnoea, unsteady gait, stagger, apathia, tremors, opacity of cornea. Deaths occurred within 5 days after exposure. Survivors were not free of symptoms when sacrificed at the end of the 14-day observation period. This study was done similar to OECD guideline 403.

An inhalation hazard test was carried out (BASF, 1971) using female rats with concentrations of 27.78 mg/l for 10-min exposure, 43.8 mg/l for 30 -min exposure and 35.1 mg/l for 60-min exposure. After 10 minutes with 27.78 mg/l no animal died within the 7-day observation period. The 30-min exposure (43.8 mg/l) was lethal for all 6 animals (2/6 died during the exposure; 2/6 after the exposure and 2/6 one or two days after exposure). At 60-min exposure time (35.1 mg/l) all animals died during the exposure period. Clinical signs were heavy attempts to escape, eye irritations, dyspnoea and labored breathing at all exposure times + dark brown eyes for the 60-min exposure. This test was done according to Smyth et al., 1962.

Another inhalation hazard test (BASF, 1979) using 3 male and 3 female rats with concentrations of 24.32 mg/l for 10-min exposure, 22.10 mg/l for 30-min exposure and 21.2 mg/l for 1-hour exposure resulted in no deaths after 10 minutes (24.32 mg/l), one death after 30-min exposure and all animals died at the 1-hour exosure period (21.2 mg/l). Heary attempt to escape, eye irritations, eyelid closure, salivation, lacrimation, dyspnea, staggering, unsteady gait, spasms and lateral position were observed as clinical signs. This test was done according to Smyth et al., 1962.

Classification proposal for acute inhalation toxicity according to Annex I of the EU Directive 67/548/EEC with R 20 (harmful if inhaled).

Acute dermal toxicity:

In an acute dermal toxicity study similar to OECD guideline 402, a dermal LD50 value was found to be 3400 mg/kg for male and female rats (BASF, 1979). Doses of 1200, 1600, 2000, 2500, 3200 and 4000 mg/kg were used. Deaths occurred within 7 days after dosing, predominantly during the first two days. Clinical signs seen were poor conditions, apathy, dyspnoea, staggering, unsteady gait, abdominal position, paresis. Local skin effects after 24 hours comprised substance-induced staining and intense swelling and necrosis after 48 hours.

Classification for acute dermal toxicity according to Annex I of the EU Directive 67/548/EEC is not warranted.