It is currently the basis for a law in Sweden that would ban the use of any substances that do not decompose in the environment and bio-accumulate in living things. Strict interpretation of this new law has forced the Swedish glass industry to reverse the centuries old practice of placing lead in glass, since lead is perceived to represent a threat to the environment. Proponents of the precautionary principle argue that it reduces the risk associated with the introduction of new technologies. Its opponents believe that its use would strongly inhibit the development of needed new technologies. There is an extensive literature dealing with risk-benefit analysis.
Risk is an objective, quantitatively measurable entity.
It is determined by counting the number of adverse outcomes associated with a given activity and dividing that number by the total number of exposures to that activity. Safety, on the other hand, is a subjective judgement. In this case, the use of DDT for malaria control is judged to be a benefit by some and a risk by others. This asks that a negative premise be proven, a logically impossible task. Whether those risks are judged to be acceptable is what should determine whether a technology is appropriate for use in society.