Methyl formate

Endpoint summary

Description of key information

Methylformiate was slightly irritating to rabbit skin under 24-hour occlusive contact (similar to OECD TG 404 except for prolonged occlusive skin contact). Skin reactions are not expected to occur under conditions of current test guidelines (semiocclusive, up to 4 hours skin contact).
Methylformate was irritating to the eyes of rabbits (method according to US Federal Register guidelines).
Methylformate showed signs consistent with respiratory tract irritation in acute inhalation toxicity studies.  

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

Skin irritation:

Undiluted methylformate was examined according to the method described in the Federal Register (FR, Title 16, section 1500.41) in rabbits (3 rabbits, occlusive skin contact for 24 hours). At the end of the observation period edema was noted in 2 of 3 animals, and a primary irritation index of 0.67 was calculated, which indicated a weak potential for skin irritation (BASF AG, 1979; Fraunhofer-Gesellschaft, 1979).

However, current test guidelines require skin contact periods of up to 4 hours. The 24-h, occlusive exposure is no longer in line with current guidelines and it may be regarded as a "severe-case" situation. Given the weak skin reaction under such conditions it may be assumed that methylformate is not irritating when tested according to current guidelines.

Eye irritation:

Undiluted methylformate was examined in three white rabbits according to a method described in the Federal Register (FR, Title 16, section 1500.42). Moderate to slight corneal opacity was seen in 2 of 3 animals after 24 hours. Opacity subsided, but was still present (grade 1) at 72 hours, covering approximately 50 % of the corneal area. Grade 1 iritis was also seen in 2 of 3 animals at 24 and 72 hours post treatment. The conjunctivae showed grade 2 reddening in 2/3 animals at 24 and 72 hours, grade 1 erythema in all animals at 24 hours, grade 2 and 1 at 72 hours in 2/3 animals, and grade 2 and 3 discharge in 2/3 animals at 24 hours, grade 1 and 2 in 2/3 animals at 72 hours. Thus the substance was irritating to the eyes (BASF AG, 1979; Fraunhofer-Gesellschaft 1979).

Respiratory tract irritation:

Methylformate showed signs consistent with respiratory tract irritation in acute inhalation toxicity studies (OECD TG 403).

Effects on eye irritation: irritating

Effects on respiratory irritation: irritating

Justification for classification or non-classification

Skin irritation:

No classification required. Methylformate caused slight skin irritation under severe case conditons (24 hour occlusive skin contact; first reading within 30 minute safter patch removal) exceeding current test guidelines. Skin reactions were reversible and did not meet the criteria for skin irritation as laid down in regulations 67/548/EC or 1272/2008/EC.

Eye irritation:

Methyl formate is classified according annex 1 of Regulation 67/548/EC and annex VI of Regulation 1272/2008/EC as follows:

Regulation 67/548/EC:

Xi; R36/37; R36/37 : Irritating to eyes and respiratory system.

Regulation 1272/2008/EC:

Eye irritation 2 (i.e. reversible effects); H319

Respiratory tract irritation:

Regulation 67/548/EC:

Xi; R36/37; R36/37 : Irritating to eyes and respiratory system.

Regulation 1272/2008/EC:

STOT SE 3; H335