Occupational health surveillance is required by law for some occupations, activities or when certain substances are used. If your job involves working with noise, vibration, solvents, some metals or other hazardous substances, then this might be the case for your employees. Occupational health surveillance is not required for most workers. If there is any doubt as to whether or not it is required then you should seek advice from a competent person, such as an occupational health or health and safety professional.