The human ear is sensitive and delicate and can detect very small changes in sound pressure. Loud noise, whether continuous or impulse, can cause permanent damage to the ear and result in hearing loss.
Many countries have legislation in place to protect workers at risk of being exposed to dangerously loud noise, usually deemed to be 90dB(A) and above. In welding and allied industries noise levels are likely to exceed these, and it is often difficult to engineer a reduction in noise.
Hearing protection, in the form of ear plugs and ear muffs, is available and must be worn in noisy areas if workers are to prevent themselves suffering noise induced industrial deafness.