Because pesticides are designed to kill living organisms, they are potentially harmful to people. Through carelessness, delibrate misue and accidents, people exposed to pesticides and their residues may be seriously harmed and even killed. To protect human health, people working with agricultural chemicals must be throughly familiar with their safe use. This unit will discuss aspects of safe pesticide usage that apply to all pesticides. Then, pesticides whose major effects on the respiratory system will be discussed in detail.