A new study has found elevated levels of benzene, a human carcinogen, in a string of top-selling dry shampoo brands. Researchers at Valisure, a New Haven, Connecticut-based independent analytical laboratory, tested 148 batches from 34 different brands using industry-standard GC-MS technology. Among the dry shampoo’s tested were those from the brands Redken, Not Your Mother’s, Sebastian, Batiste, OGX, and Paul…