The U.S. Public Health Service has conducted studies to evaluate the potential hazard of pesticides to three segments of the population. The segment that includes the formulator, spray or dust machine operator, or other workers having closest contact with pesticides was found to have the greatest potential exposure. If they do not follow the recommended safety precautions when working with hazardous compounds, they may risk illness or death. The exposure to persons having only incidental environmental exposure as a result of spray or dust applications appears generally to be too small to constitute a significant health hazard. There have been no cases of illness in this country from insecticide residues on food when formulations have been used according to directions, but there have been when recommendations were ignored. Each year tragic preventable poisonings occur when children come in contact with so-called 'empty' pesticide containers or drink from beverage bottles or other containers that have been carelessly used for storage of small quantities of liquid pesticide.