N,N-dimethylhydrazine

Endpoint summary

Description of key information

The substance is already subject of a harmonized classification as Skin Corr 1B; H314. Therefore no robust summary was produced, however the following (non-Klimisch rated) data were found in the literature:

- Extensive skin burns occurred in a 31-year-old man. Acute human exposure to a 1:1 v/v mixture of a hydrazine/UDMH mixture in air notably resulted in burning of the skin.[3]

- A single application of 3 μL directly to the eyes produced conjunctivitis and erythema of the eyelids in rabbits;[1] however this dose is 33 times lower than the OECD 405 requirement.

- Lung irritation has been noted in dogs after intermediate-duration exposure to 25 ppm but not 5 ppm. Inflammation, hyperplasia and dysplasia of the nasal mucosa were noted in mice chronically exposed to 5 ppm. Hyperplasia of the alveoli and lymphoid tissue of the lung was observed in rats and mice exposed to 0.05 ppm for 6 months. A higher concentration (0.5 ppm) produced congestion and perivascular cuffing in the lungs of these mice. Intermittent exposure to 5 ppm UDMH for 1 year produced inflammation, hyperplasia and metaplasia of the upper respiratory tract epithelium in rats and mice. In mice exposed to 0.05-5 ppm for 6 months to 1 year, the blood vessels were abnormally dilated (angiectasis).[1]  Acute human exposure to a 1:1 v/v mixture of a hydrazine/UDMH mixture in air notably resulted in dyspnea and pulmonary edema in one worker and sore throat in the other.[1,2,3]

References of the reviews/sources:

[1] ATSDR. Toxicological profile for hydrazines. 1997

[2] WHO. Environmental Health Criteria 68 on Hydrazine. 1987

[3] HSDB. 1,1-DIMETHYLHYDRAZINE, CASRN: 57-14-7

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (corrosive)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

The substance is already subject of a harmonized classification as C (corrosive), R34.

Overall, the literature data that could be localized support this classification which is relevant for skin and eye effects.

However, the clear potential of respiratory irritation evidenced by animal and human data is not taken into account in this classification.

Effects on skin irritation/corrosion: corrosive

Effects on eye irritation: corrosive

Effects on respiratory irritation: irritating

Justification for classification or non-classification

The substance is already subject of a harmonized classification as C (corrosive), R34. This classification is agreed upon by registrants.

However, for the current directive (DSD), risk phrase R37 "Irritating to respiratory system" should be added due to weight-of-evidence data from animals and humans. This risk phrase refers to STOT SE 3, H335 under the new classification methods (CLP).