1-bromopropane

Endpoint summary

Description of key information

An acute dermal irritation study was performed on 1-bromopropane using albino rabbits (24 hour exposure, tests sites both intact and abraded) representing a worst case scenario for assessing irritation.
Edema was observed in one out of the six animals tested. No eschar formation was observed. 1-bromopropane is considered as a non-irritant. However  signs of ulceration and necrosis were seen in all dose levels of the available acute dermal toxicity test (Paster (1979)).
An acute eye irritation study was performed on 6 male rabbits. Grading of eye irritation was according to the scale of Draize and the Illustrated Guide for Grading Eye Irritation published by the F.D.A. Scoring method was that of the Consumer Product Safety Commission, Federal Register vol. 38, No. 187, 1500.42. Since two out of the six animals tested exhibited a positive reaction, the test was repeated using a group of six different rabbits. The second test was considered positive since three animals out of six tested exhibited positive reactions. 1-bromopropane is considered an eye irritant.
Acute respiratory irritation was observed during the Schorsch (1997) study (see section 7.2, Acute toxicity: inhalation.001) and was found to cause mortalities at concentrations above 30200 mg/m³. 

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

Effects on skin irritation/corrosion: irritating

Effects on eye irritation: irritating

Effects on respiratory irritation: irritating

Justification for classification or non-classification

According to section 3.2.6.1 of Directive 67/548/EEC, the substance does not meet the quantitative criteria for classification as irritating to the skin (R38). However, section 3.2.6.1 also states relevant data may also be available from non-acute animal studies, which should be considered significant if the effects seen are comparable to the quantitative criteria. A high dose dermal toxicity study on n-propyl bromide in rabbits by Paster (1979) indicates skin ulceration and necrosis at all doses (range 2.5 – 10 mL/kg, approximately 3375 – 13,500 mg/kg). Although both the skin irritation study and the dermal toxicity study both used 24 hour exposure times, it should be noted that the dose volumes used for the dermal toxicity study were substantially higher than for a standard dermal irritation study, which may account for the differences in irritation responses seen between the two studies. However, given the effects seen in the dermal toxicity study, n-propyl bromide may require classification as a skin irritant (R38).

The eye irritation study data available indicates that n-propyl bromide is an eye irritant, and as such the substance requires classification accordingly (R36).

Substances which cause serious irritation of the respiratory system based on either practical observation in humans or positive results from appropriate animal tests should be classified as irritating to the respiratory system (R37). An acute inhalation study on n-propyl bromide by Schorsch (1997) dosed rats at 30 to 42 g/m3 and reported inflammation and oedema in the lungs. n-propyl bromide therefore requires classification as a respiratory system irritant.

Taking the above into account, n-propyl bromide is officially classified as Xi, R36/37/38 on Annex I of Directive 67/548/EEC and as a Skin Irritant Category 2, and Eye Irritant Category 2 and a STOT SE Category 3 on Annex VI of the EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.