Hydrocarbons, C6-C7, n-alkanes, isoalkanes, cyclics, <5% n-hexane

Endpoint summary

Description of key information

Irritating to the skin.
Not irritating to the eyes.

Additional information

Two studies of ExxonMobil (1990 and 1992) showed irritating effects to the skin of rabbits based on persistent irritation at study termination. ExxonMobil (1990) examined the skin irritation of the hydrocarbons, C6-C7, n-alkanes, isoalkanes, cyclics, <5% n-hexane, conducted similar to OECD 404. 0.5 mL of test substance was applied on the clipped skin of 6 rabbits, and covered with a semi-occlusive patch. After 4 hours of exposure, the test substance was removed. Animals were scored for dermal irritation 45 min, 24, 48, 72 hours and 7 days after patch removal. All animals exhibited very slight to well-defined erythema. In 3 of 6 rabbits, very slight edema were observed. These symptoms were mostly reversible within 7 days. However, three animals still showed irritating symptoms at the study termination. Desquamation was noted in two animals at day 7 of the observation period. In a subsequent study of ExxonMobil (1992), the skin irritation potential of the test substance was determined according to the study design of ExxonMobil (1990). No edema was noted, but all animals exhibited very slight to well-defined erythema. In 5 of 6 rabbits, these symptoms were not reversible within the observation period of 7 days. Desquamation was also noted in 5 of 6 animals at the study termination.The test substance is skin irritating based on persistant irritation at the end of the observation period of 7 days. An observation period of 14 days was not considered in the study.

In contrast, the skin irritation potential of the hydrocarbons, C6-C7, n-alkanes, isoalkanes, cyclics, <5% n-hexane was determined according to OECD 404 (Shell, 1987) yielding a negative result. The test substance was applied to the intact skin of rabbits for 4 hours under semiocclusive conditions. After removal of the test substance, no edema, but very slight erythema were noted. At 72 hours 3 of 6 rabbits were still affected. All skin effects in all treated animals had cleared by 7 days.

There are no eye irritation data available on the hydrocarbons, C6 -C7, n-alkanes, isoalkanes, cyclics, <5% n-hexane. However, there are reliable data available for another category member. Thus, read-across was conducted based on a category-approach.

The eye irritation potential of the hydrocarbons, C7-C9, n-alkanes, isoalkanes, cyclics was determined by instillation of 0.2 mL of the test material into the conjunctival sac of 4 rabbits (Shell, 1977). A visual assessment of irritancy was made 30 min, 24, 48, 72 hours and 7 days after application. At 30 min after application, a very mild irritancy was observed in mild conjunctival redness (grade 0-1) in all animals. All redness was reversible within 24 hours. No corneal opacity, iritis, conjunctival chemosis, or discharge was noted in any of the 4 rabbits.

Justification for classification or non-classification

Based on the available data, hydrocarbons, C6-C7, n-alkanes, isoalkanes, cyclics, <5% n-hexane were considered as skin irritant.

DSD: R38

CLP: Skin Irritation Category 2