The principles of dealing with working environments where occupational respiratory disease occurs are discussed. The choice of abatement strategies depends on the particular process, the physical structure of the equipment, and the rate of aerosolization of the allergen. When feasible, primary effort should be placed on preventing aerosolization. Increased ventilation and air filtration are feasible only when allergen production rate is low or localized to areas where exhaust fans can remove it before it reaches the breathing zone of the workers. The aim of controlling exposure is to reduce the concentration of the allergen in the air below the level that causes disease. Preventing spills or other accidental reasons for occasional high concentrations is usually a matter of design of the manufacturing, cleaning, and air handling equipment and its proper maintenance. Reduction in steady stage concentrations can be achieved by three different strategies: reduced source generation or aerosolization; increased ventilation; and air filtration.