Toner Dust & VOCs of Printers and Copiers   Toner dust emissions from dry-process photocopiers and laser printers may cause respiratory illness and allergic reactions. Minute particles of silicon, iron, copper and aluminum are elements commonly used in toner powder. When toners are heated to the temperatures in the fusers, they release minute toner dust particles and other hazardous gases.   A wide variety of occupational lung diseases, ranging from asthma to coal miner's "black lung" disease, are known to be caused by breathing airborne metal or mineral dusts.   When metal dusts are inhaled, it can build up in the lungs and lymph nodes. The lung and lymph tissue may react by developing small lumps, or granulomas. With prolonged exposure, the lumps may enlarge, multiply, and eventually grow together, causing lung fibrosis. This will seriously impair the breathing functions.     The toners of copiers and printers are the major source of volatile organic compounds (VOCs) from these machines. In addition, photocopiers, computers, printers, and other office machines release VOCs from plastic casings and other construction components, such as the printed circuit board. These VOCs may trigger allergic reactions and other health problems. (more info on VOCs)   To reduce exposure to toner dust and related VOCs, printing and copying machines should be placed in well-ventilated rooms. In the office environment where large numbers of photocopiers and laser printers are used, these machines should be clustered in isolated areas with separate ventilation systems.