2-chloroethanol

Endpoint summary

Description of key information

The acute oral LD50 value of 2-chloroethanol derived from the key study in rats (BASF AG, 1978) is 77 mg/kg bw. 
The acute inhalation LC50 value (4 h) in rats is between 16 ppm (53 mg/m³) and 62 ppm (207 mg/m³).
The acute dermal LD50 value of 2-chloroethanol derived from the key study in rabbits (Lawrence et al., 1971) is 68 mg/kg bw.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

77 mg/kg bw

Acute toxicity: via dermal route

Endpoint conclusion

Dose descriptor:

LD50

Value:

68 mg/kg bw

Additional information

In the acute oral toxicity key study (BASF AG, 1978) groups of 5 male and 5 female rats were gavaged with 1 or 2% aqueous solutions of 2 -chloroethanol at dose levels of 60, 77, 96, 120 and 240 mg/kg bw. The post exposure observation period was 14 days. Clinical signs occurred immediately after gavage: rats kept calm and showed delayed movements, after ca. 1 h prone or side position, apathy, reduced muscle tonus, abnormal respiration, redened eyes, and next day additionally bloody muzzle; no clinical signs were observed later than day 8. At the high dose levels rats died mainly within 4 h, later deaths were also observed. Generally, females died earlier than males. Necropsy revealed dilatated heart, sallow musculature, yellowish liver & kidney, hemorrhagic ulcer of the stomach, intestinal content soft and reddened; no effects were detected in surviving rats. The test substance is toxic if swallowed. The oral LD50 is 77 mg/kg bw in male and female rats combined.

Five further acute oral toxicity studies (Van der Heuvel et al., (1990); Laurenz et al., (1971); Goldblatt et al., (1944); Weisbrod et al., (1980); Sauvant et al., (1995)) in rats are in line with this result, the LD50 value was between 60-90 mg/kg bw.

Two acute oral toxicity studies (Weisbrod et al., 1990); Lawrence et al., (1971)) with mice revealed a LD50 value of 81 and 150 mg/kg bw, respectively.In an acute oral toxicity study (MAK et al., (1973)) with guinea pigs the LD50 value was 110 mg/kg bw.

In the acute inhalation toxicity key study (Carpenter, 1949), six Sherman rats per dose level were exposed for 4 hours to 2 -chloroethanol concentrations varied in a geometric progression increasing by a factor of 2. The post exposure observation period was 14 days. At a concentration of 32 ppm (107 mg/m³) 2 -4 out of 6 treated rats died. No further details were reported in the result section. However, it can be assumed that a concentration of 16 ppm resulted in no mortality or only 1 death in 6 treated rats and at a concentration of 62 ppm more than 4 out of 6 treated rats died. Conclusion: Rough estimation of LC50 (4 h) in rats: 16 ppm (53 mg/m³) < LC50 < 62 ppm (207 mg/m³).

BASF AG (1973) conducted an acute inhalation toxicity study in which rats exposed to saturated vapour (calculated concentration of 2-chloroethanol: 8 -20 mg/l) died after an exposure period >= 10 minutes. In a study of Lawrence et al., (1971/1972) the LT50 in mice, exposed to nearly saturated vapour, was described with 6.5 min and 13.3 min. The publication of Goldblatt et al., (1944) detected lethal effects at 2000 mg/m³ 2 -chloroethanol after an exposure duration of 120 min in the rat. Ambrose et al., (1950) indicated lethal effects at 13.4 mg/m³ (4 ppm) in rats after two exposures of one hour each, with a two hour interval. A concentration of 6.7 mg/m³ (2 ppm) did not cause death after a single exposure (presumably 1 h) but produced paralysis in some rats, and finally death, after repeated exposures. In a study (NTP, 1985) with mice, the LC50 value was 117 ppm.

In the acute dermal toxicity key study (Lawrence et al., 1971) groups of 4 -5 rabbits (males and females) were dermally exposed to graded doses of undiluted test substance for 24 h (test substance added to patches and these secured by polyethylene overwrap). The post exposure observation period was 7 days. The authors calculated a LD50 of 68 mg/kg bw. An acute dermal toxicity study conducted by BASF AG (1973) described a LD50 value of 240 mg/kg bw in the rabbit. Ambrose et al., (1950) demonstrated that rabbits, exposed to 600 mg 2 -chloroethanol (corresponding approximately 300 mg/kg bw) by single dermal application, survived 24 hours.

In an acute dermal toxicity study (NTP, 1985) groups of 5 male and 5 female Swiss-Webster mice were dermally exposed to the test substance solved in 80% ethanol. Six different dose levels were tested. The mice died within 1-4 days after application. The survivors were observed for 14 days.The LD50 value in male mice was 1300 mg/kg bw and in females 1940 mg/kg bw. In a second acute dermal toxicity study (Goldblatt et al., (1944)) LD50 value in mice was of 1500 mg/kg bw was reported.

An acute dermal toxicity study was conducted by NTP (1985). Groups of 2 -8 male and 2 -9 female F344/N rats were dermally exposed to the test substance solved in 80% ethanol. The dose level varied between 38 and 2957 mg/kg bw in males (11 dose levels) and in females between 55 and 3713 mg/kg bw. The rats died within 4 h after application. The survivors were observed for 14 days. The steepness of the dose-response curve in males did not allow a calculation of the LD50 value.Thus, the LD50 value in male rats was between 330 and 470 mg/kg bw and in females the LD50 value was 416 mg/kg bw. Ambrose et al., (1950) conducted a study in which 150 mg 2 -chloroethanol/animal (corresponding approximately 375 mg/kg bw) was lethal in rats after dermal application.

In a study of Wahlberg et al., (1978) five to 20 guinea pigs per dose level received dermal application of 80 -6450 mg/kg bw (7 dose groups). Pure test substance (high dose levels) or dilutions in water were applied. The post exposure observation period was 14 days. At 320 mg/kg bw 20 out of 20 animals died within the 1st day after application. Graphical estimation resulted in a LD50 of 260 mg/kg bw. According to MAK et al., (1983), the LD50 value for acute dermal toxicity in guinea pigs was determined to be 84 mg/kg bw.

Justification for classification or non-classification

Based on the available data the test item is subject to C&L

according to Regulation 1272/2008/EC: acute oral tox. 3, H301; acute dermal tox.2, H310; acute inhalation tox. 1, H330

according to Directive 67/548/EEC: acute oral tox.: R25; acute dermal tox.: R24, acute inhalation tox: R26

2 -Chloroethanol is included in Annex VI of Regulation 1272/2008/EC with the following classification:

Table 3.1: acute oral tox. 2*, H 300; acute dermal tox. 1, H310; acute inhalation tox. 2*, H330

Table 3.2: R26/27/28