Identifying Chemicals of Health Concern in Hair Extensions Using Suspect Screening and Nontargeted Analysis

Area of Science:

• Environmental Health
• Analytical Chemistry
• Toxicology

Background:

• Chemical exposures from hair extensions are a growing public health concern.
• Limited regulatory oversight and poorly characterized compositions of hair extensions contribute to risks.
• Hair extension use may exacerbate existing health disparities.

Purpose of the Study:

• To comprehensively analyze the chemical composition of hair extension samples.
• To identify and classify potential chemical hazards present in hair extensions.
• To inform public health and regulatory strategies regarding hair extension safety.

Main Methods:

• Utilized nontargeted analysis (NTA) on 44 hair extension samples.
• Employed two-dimensional gas chromatography-high-resolution mass spectrometry for chemical detection.
• Used machine learning (Highlight platform) and NIST library for chemical feature annotation.

Main Results:

• Detected 933 unique chemical signatures, with 5,275 total detections across all samples.
• Confirmed and tentatively identified 169 chemicals, classifying their potential hazards.
• Found hazardous organotin compounds in nearly 10% of samples, with some exceeding 0.4% tin by weight.

Conclusions:

• Hair extensions contain a wide array of chemicals, including hazardous substances like organotins.
• Forty-eight identified chemicals are listed on California's Proposition 65 hazard list.
• Further research and policy interventions are needed to mitigate health risks associated with hair extension chemicals.