The nail salon workforce: a systematic scoping review of carcinogen exposure assessments, health outcome, and workforce intervention research

Nail salon workers are routinely exposed to occupational hazards, including volatile organic compounds (VOCs), ultraviolet radiation, fine particulate matter (PM_2.5), and heavy metals. With the industry projected to double in size over the next decade, identifying exposure risks and intervention gaps is essential for workforce protection. This systematic scoping review synthesized peer-reviewed exposure assessments, health outcome studies, and intervention research in nail salons published between 2013 and 2024. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and the National Institute of Environmental Health Sciences National Toxicology Program Handbook for Conducting Systematic Reviews. Risk of bias was assessed using the Strengthening the Reporting of Observational Studies in Epidemiology guidelines. Forty-two studies met inclusion criteria: 29 exposure assessments, 11 health outcome studies, and two intervention evaluations. Most were conducted in the U.S. (88 %), with sample sizes ranging from 20 to 150 workers. Common findings included inadequate ventilation (71 %), VOC concentrations above Occupational Safety and Health Administration limits, and persistent detection of methyl methacrylate, despite its U.S. Food and Drug Administration ban. PM_2.5 was evaluated in one study and exceeded World Health Organization guidelines. Heavy metals were infrequently measured, though one study raised concerns about chronic exposure. Only 17 % of studies examined exposure–health outcome associations, with limited evidence on cognitive and psychosocial impacts. Two intervention studies reported improved knowledge and reduced exposures but lacked randomized designs. This review highlights the urgent need for evidence-based interventions, stronger regulatory oversight, and comprehensive evaluation of health impacts in this socially vulnerable workforce.