Overview
- Silent Spring Institute tested 43 popular synthetic and human-hair products and identified 169 chemicals, with 41 samples containing hazardous substances.
- Detected compounds included flame retardants, phthalates, pesticides, styrene, tetrachloroethane and organotins, with 48 chemicals on major hazard lists and 12 on California’s Proposition 65.
- Nearly 10% of samples contained organotins, some above European Union limits, and researchers flagged 17 chemicals linked to breast cancer across 36 products.
- Extensions sit on the scalp for weeks and release chemicals when heated or styled, raising exposure concerns that weigh heavily on Black women, more than 70% of whom report using extensions yearly.
- The study used non‑targeted 2D gas chromatography with high‑resolution mass spectrometry and machine learning to match over 900 signatures, and only two “non-toxic” or “toxic-free” products—identified by NBC as Rebundle and Latched & Hooked—tested free of hazardous chemicals.