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Description of key information

One key skin irritation study (similar to OECD 404) was identified. Although this test is valid in its methodology, it differs from the current OECD guidelines in that animals were exposed under occluded conditions for 24 hours instead of semi-occluded conditions for 4 hours.  Considering the conditions of the test, results must be interpreted carefully for the purposes of classification and labelling.  The mean scores for erythema and oedema have been assessed against the deviations, and provided the test would be conducted under standard conditions, slight irritation might be expected but insufficient to classify.  

One key eye irritation study (OECD 405) was identified, in which the test material was not irritating to the eyes of rabbits.

Supporting skin and eye irritation studies are available and results are consistent with those seen in the key 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:
no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Straight run gas oils are not considered to be irritating to the skin or eyes.

Skin Irritation

A straight run middle distillate was tested for primary dermal irritancy in New Zealand White rabbits (API, 1985a; Klimisch score=2). The sample (0.5 mL) was applied to intact and abraded clipped skin on the back and flank of 6 rabbits, under occlusion for 24 hours (current guidelines now recommend semi-occluded exposure for a period of 4 hours). For intact skin, the mean erythema and oedema scores over 24 to 72 hours were 1.80 and 1.58, respectively, indicating that the test material is not irritating. 

A supporting study on intermediate gas oil (CAS# 64741-43-1) resulted in mean erythema and oedema scores over 24 to 72 hours of 2.28 and 2.83, respectively, indicating that the test material is not irritating (ARCO, 1992a; Klimisch score = 2).

Although these tests are valid in their methodology, they differ from the current OECD guidelines in that animals were exposed under occluded conditions for 24 hours instead of semi-occluded conditions for 4 hours. Considering the conditions of the tests, results must be interpreted carefully for the purposes of classification and labelling. The mean scores for erythema and oedema have been assessed against the deviations, and provided the tests would be conducted under standard conditions, slight irritation from exposure to straight run gas oils might be expected but insufficient to classify. 

Eye Irritation

In a primary eye irritation study, 0.1 mL of straight run distillate was instilled into the conjunctival sac of one eye of each of nine young adult New Zealand White rabbits (API, 1985a; Klimisch score = 1). The eyes of three rabbits were washed twenty to thirty seconds after instillation. The eyes of the remaining six rabbits were not washed. Animals were observed 1, 24, 48, and 72 hours and at 7 days after treatment. No pain response (vocalization) was elicited from any animal following instillation of the test material. No corneal irritation was seen during the study. All irritation had cleared by the 48-hour observation. No sign of systemic toxicity was observed during the study.The conjunctivae, iridial and corneal scores at 24, 48 and 72 hours post-exposure averaged out to 0. Irritation was scored by the method of Draize. Consequently, the test material is not irritating to the eyes.

A supporting study on intermediate gas oil (CAS# 64741-43-1) resulted in mean corneal and iridial scores over 24 to 72 hours of 0, and a mean conjunctivae score of 0.67, indicating that the test material is not irritating to the eyes (ARCO, 1991a; Klimisch score = 2).

Justification for selection of skin irritation / corrosion endpoint:

well conducted study but with 24hr occluded exposure.

Justification for selection of eye irritation endpoint:

well conducted guideline study

Justification for classification or non-classification

Straight run gas oils do not meet the criteria for classification as a skin or eye irritant according to EU CLP (EC No. 1272/2008).

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