We tried to address this issue several years ago. There were objections that prohibiting leggings or lycra style attire was discriminatory because they were mostly worn by ladies. So we compromised and require that in addition to a lab coat, all skin on legs, ankles and feet must be completely covered. We may recommend that synthetic fabric that stretches over the skin should not be worn when working with corrosives and solvents, but only suggest, because some socks are also made from these types of fabrics. Enforcement is easy, any student with skin showing below the lab coat must leave the lab. I hope this helps.