The principle is to be applied to all GMOs whether used as food or as seeds for environmental release. The precautionary principle states that when there is reasonable suspicion of harm, lack of scientific certainty or consensus must not be used to postpone preventative action. There is indeed sufficient direct and indirect scientific evidence to suggest that GMOs are unsafe for use as food or for release into the environment. The precautionary principle is actually part and parcel of sound science. Science is an active knowledge system in which new discoveries are made almost every day.
Scientific evidence is always incomplete and uncertain.
The responsible use of scientific evidence, therefore, is to set precaution. This is all the more important for technologies, such as genetic engineering, which can neither be controlled nor be recalled. Dr. Peter Saunders, Professor of Applied Mathematics at King's College London, co-Founder of ISIS, has written an article which shows how the precautionary principle is just codified common sense that people have accepted in courts of law and mathematicians have adopted in the proper use of statistics. It begins to clarify how scientific evidence is to be interpreted in a socially responsible way which is also in accord with sound science. There has been a lot written and said about the precautionary principle recently, much of it misleading.