Formamide

Endpoint summary

Description of key information

Skin irritation is not likely, based on low level rabbit skin reactions observed after severe case exposure conditions (20 hours, occlusive).
Reversible irritation of the rabbit's eye was seen at a level not requiring classification and labelling according to regulation 67/548/EC.
There were no signs indicating respiratory irritation in rats exposed to formamide vapours near saturation in acute Inhalation Hazard Tests. 

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:

no adverse effect observed (not irritating)

Additional information

Skin irritation

In a pre-guideline study, formamide, applied to the shaved back skin of 2 rabbits for 20 hours under an occlusive dressing, caused marked erythema at 24 hours and slight erythema at 24 and 48 hours after initiation of treatment. Erythema was absent on day 5, and scaling was seen at the treated sites. A 20-hour occlusive exposure exceeds by far current test guideline exposure conditions and represents very severe conditions. Only very slight signs of irritation were seen under these conditions (Key study). Therefore, the type and severity of the effects suggest that formamide is not irritating when these results are extrapolated to a 4 -hour semi occlusive exposure which is currently required for in-vivo testing.

 

Observations in a 90-day dermal rat study (exposure semiocclusive, 6 hours/day, 5 d/week) support this, though rat skin is less susceptible than the rabbit's skin. Erythema were seen in rats receiving 3000 mg undiluted formamide/kg bw/day only in the second half of the study, i.e. during 12th and13th week of treatment (see Key study under repeated dose toxicity (dermal)). It is therefore concluded that formamide is not irritating to the intact rat skin.

Eye irritation

In an eye irritation study conducted according to OECD TG No. 405, 0.1 mL of formamide was applied into the lower conjunctival sac of 6 New Zealand White rabbits. The eye reactions were scored according to the table of Draize contained in the test guideline at 4, 24, 48, 72, and 96 after treatment. Conjunctivitis was the most prominent effect, the other effects were milder. The effects were reversible. The mean scores at 24, 48, and 96 hours were as follows: cornea score: 0.2; iritis 0.2; conjunctivitis: 1.93; and chemosis 0.43. Thus, there was reversible mild eye irritation seen at a level not requiring classification according to the regulations 67/548/EC and 1272/2008/EC (Key study).

Respiratory irritation

There were no signs indicating respiratory irritation in rats exposed to formamide vapours near saturation in acute Inhalation Hazard Tests.

Effects on eye irritation: slightly irritating

Justification for classification or non-classification

No classification required for skin irritation; eye irritation; respiratory irritation because criteria of regulations 67/548/EC and 1272/2008/EC are not met.