Laterality of hand-arm vibration exposure during grinding operations: a field study in industrial settings.

Introduction: Occupational exposure to hand-arm vibration generated by the use of powered hand tools is a major risk factor for workers' health, particularly when combined with high levels of occupational noise. Among these tools, angle grinders used by welders are recognized as important sources of both physical hazards. Objectives: To investigate the laterality of hand-arm vibration exposure among workers using 7-inch and 9-inch electric angle grinders by comparing vibration exposure between the control hand positioned on the rear handle and the supporting hand positioned on the front handle as well as to assess the intensity of occupational noise generated by these tools. Methods: A retrospective observational study was conducted involving six welders from three companies representing different industrial sectors under real-world working conditions. Vibration and noise measurements were performed in accordance with the procedures established by Brazilian Occupational Hygiene Standard 10 and Brazilian Occupational Hygiene Standard 01, using the normalized resultant acceleration and A-weighted sound pressure levels expressed in dB(A). Results: Hand-arm vibration exposure showed an asymmetric pattern, with higher vibration levels consistently recorded at the rear handle (control hand), regardless of tool size or grinding disc type. In all samples, vibration levels exceeded the action value and, in some cases, surpassed the occupational exposure limit established by Brazilian legislation. Noise levels also exceeded the action value, with no evidence of lateral predominance. Conclusions: These findings highlight the importance of measuring vibration exposure in both hands and reveal gaps in the current regulatory framework regarding objective criteria for the simultaneous assessment of hand-arm vibration exposure.