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Additional information

4-Hydroxyacetophenone was tested for skin irritation under occlusive conditions using rabbits (UBTL Inc., 1992). The undiluted test substance was used; testing duration: 4 hours. No skin irritation was recorded.

In another UBTL study (1992), 4-Hydroxyacetophenone was dissolved with tetrahydrofurane, dimethylsulfoxide, methanol or N,N-dimethylformamide (30%, 15%, 5% and 3% in either vehicle). Rabbits were applied occlusive for 4 hours. Based on the results of this experiment, 4-Hydroxyacetophenone does not significantly increase the dermal irritancy of THF, DMSO, methanol or DMF.

The acute eye irritation was reported by UBTL Inc. (1992). 0.1 g of the undiluted test substance was used (study duration: 24 h).

Results for the initially treated animal that remained unrinsed: At the 1 h reading corneal opacity 2 was noted with the area involved ranging from 50 to 75%: Conjunctival redness 2, chemosis 3 and discharge 2 were also noted. At the 24 h reading corneal opacity 2 was noted with the area involved ranging from 75 to 100%. Iridial irritation 1 was noted. Conjunctival redness 2, chemosis 3 and discharge 3 were also noted. Fluorescein staining of the corneal epithelium was evident with the area involved ranging from 75-100%.

Hair loss below the lower eyelid was also seen which remained the same until day 14 when new hair started growing in the area. At the 72 h reading corneal opacity 2 was noted with the area involved ranging from 50-75%. Iridial irritation 1, conjunctival redness 2, chemosis 2 and discharge 3 were still noted. Fluorescein staining was evident with the corneal area involved ranging from 25-50%. On day 21 of the study, the unrinsed animal was free of ocular irritation. The maximum Draize score was recorded 48 h after treatment and was 63/110.

Results for the animals of the rinsed group: The rinsed eyes showed somewhat milder conjunctival effects which were completely resolved by observation day 7. Slight corneal opacity was reported in 2/3 animals but only at the 24-h reading. On day 7 of the study, all of the rinsed animals were free of ocular irritation. According to the authors, the classification of the test material is considered to be a severe irritant based upon the maximum total score of 63 calculated for the initially treated rabbit, that remained unrinsed. The irritation appeared to be essentially fully reversible within 21 days of treatment. The rinsing procedure for the additional 3 treated animals appeared to have reduced the severity and duration of irritation. Based upon the mean total score of 22 calculated for the three rabbits in the rinsed group, the classification considered to be as a moderate irritant.

Justification for classification or non-classification

4-Hydroxyacetophenone is classified according to EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 for eye irritation (cat. 2; H319).