Electric and magnetic fields at the power line frequency (60 Hz) and its harmonics have been measured around 22 arc welders. The electric field strengths in most cases were very low (1 V m-1) and only for one device reached 300 V m-1. Magnetic flux densities ranged from a few microT to a few hundred microT (a few A m-1 to a few hundred of A m-1). Several devices surveyed produced high magnetic flux densities (200-400 microT), which are rarely encountered in the environment and are representative of high occupational exposures.