Reaction mass of methyl chloroacetate and chloroacetic acid

Endpoint summary

Description of key information

Skin irritation: 
Reaction mass of methyl chloroacetate and chloroacetic acid: Data waiving: According to column 2 of REACH Annex VII, the study does not need to be conducted since the substance is classified as corrosive to the skin. 
Monochloroacetic acid: Test method was similar to FDA guidelines. Under these conditions, the test substance was severe irritating and corrosive.
Methyl chloroacetate: read across from the analogue ethyl chloroacetate (OECD 404). 
Eye irritation: 
Reaction mass of methyl chloroacetate and chloroacetic acid: Data waiving: According to column 2 of REACH Annex VII, the study does not need to be conducted since the substance is classified as corrosive to the skin. 
Monochloroacetic acid: supporting study. Experimental results. Because of the dismal state, the animals were euthanized 24 hours after the start of the test. 
Methyl chloroacetate: Experimental results. No guideline was followed. However, the test method was similar to OECD 405.

Additional information

Reaction mass of methyl chloroacetate and chloroacetic acid:

Skin irritation:

1.- Monochloroacetic acid:

The substance is included in the harmonised classification and labelling list and it is classified as follows:

According to the CLP Regulation:

Skin corrosive Category 1B

According to the Directive 67/548/EEC:

C, R34

A study on skin irritation/corrosion was conducted with the substance. Test method was similar to FDA guidelines. Under these conditions, the test substance was severe irritating and corrosive.

2.- Methyl chloroacetate:

Based on the results observed in the skin irritation study, strong damages of the skin in the form of redness, swelling, scabbing, cracking, hardening, sheds and burns were observed. Under the test conditions described, the substance proved to have a strong skin irritant and corrosive effect. However, the duration of exposure was 24 hours instead of 4 hours as recommended in the guidelines. The study is considered to be not reliable. There is a skin irritation study conducted on the analogue ethyl chloroacetate which has been conducted according to the recommended guideline OECD 404. Based on the results obtained in this study, the substance is classified as skin irritating.

The analogue ethyl chloroacetate which shares the same functional group with methyl chloroacetate, also has comparable values for the relevant molecular properties. These properties are:

- a low log Pow value which is 0.94 -1.12 for ethyl chloroacetate and 0.63 for methyl chloroacetate,

- a high water solubility which is 20 g/l at approximately 20 ºC for ethyl chloroacetate and 51.6 g/l for methyl chloroacetate and

- similar molecular weights which are 122.55 for ethyl chloroacetate and 108.52 for methyl chloroacetate.

Furthermore, in the acute dermal toxicity studies conducted with methyl chloroacetate with rats and rabbits, no indication of necrosis is reported in the study although erythema and oedema were observed in the animals. Finally, the substance methyl chloroacetate is included in the list of harmonised classifications and labellings and it is classified as "Skin irritant Category 2".

Eye irritation:

1.- Monochloroacetic acid:

Experimental results. Because of the dismal state, the animals were euthanized 24 hours after the start of the test.

2.- Methyl chloroacetate:

Based on the results observed in the eye irritation study, the mean scores for 24-72 h for eye irritation are 2.22, 2.17 and 2.22 for cornea opacity, conjunctiva redness and conjunctiva chemosis, respectively. However, there is no information on the reversibility of the observed damage. In this context, persistent lesions are considered those which are not fully reversible within an observation period of normally 21 days. Substances are also classified in Category 1 if they fulfil the criteria of corneal opacity ≥ 3 or iritis > 1,5 detected in a Draize eye test with rabbits, recognising that such severe lesions usually do not reverse within a 21-day observation period. In this study, at 72 hours, three animals showed corneal opacity = 3. Although there is no information on the reversibility of the damage, the substance is included in the list of harmonised classifications and labelling and it is classified as "Irreversible effects on the eyes Category 1".

Respiratory irritation:

1.- Methyl chloroacetate:

Based on the results observed in an acute inhalation study, methyl monochloroacetate was found to be a pronounced irritant of the respiratory tract at levels of 250 -1000 ppm. Therefore, the substance is classified as STOT SE Category 3, H335: May cause respiratory irritation.

Justification for classification or non-classification

Monochloroacetic acid:

Skin corrosive Category 1B

Specific concentrations limits: STOT SE Category 3; C ≥ 5%

Methyl chloroacetate:

Skin irritant Category 2

Irreversible effects on the eyes Category 1

STOT SE Category 3

Conclusions:

Based on the skin and eye irritation/corrosion data for the substances mentioned above and their concentrations, the following classification is proposed following the classification criteria for mixtures included in the CLP Regulation:

Skin corrosive Category 1B (since monochloroacetic acid is present in a concentration of more than 5%).

STOT SE Category 3 (since methyl chloroacetate is present in a concentration of more than 20% and monochloroacetic acid is present in a concentration of more than 5%).