Dermal oncogenicity bioassays of acrylic acid, ethyl acrylate, and butyl acrylate.

Male C3H/HeJ mice (40 per group) were treated with 25-microliter applications of undiluted ethyl acrylate, 1% acrylic acid, or 1% butyl acrylate on the dorsal skin 3 times weekly for their lifetime. A negative control group received acetone (diluent) only, and a positive control group received 0.1% 3-methylcholanthrene (MC). No epidermal tumors were observed in the animals that received any of the three test substances. In the positive control group, 39 animals had skin tumors, including 33 with confirmed squamous-cell carcinomas. Nonneoplastic skin changes such as dermatitis, dermal fibrosis, epidermal necrosis, and hyperkeratosis were observed in several mice that received ethyl acrylate. No statistically significant effects on survival were seen. Therefore, there was no evidence for local carcinogenic activity of acrylic acid, ethyl acrylate, or butyl acrylate under the conditions of these studies.