In short, the meaning of the Precautionary principle may be described as “better safe than sorry”. Since chemicals are so infinitely difficult to assess and the potential hazard may be so severe, a precautionary perspective is essential. By eliminating hazardous substances you are also eliminating the risk for them to do any harm.The guiding principle in this approach is called the Precautionary principle. . In 1992, the United Nations adopted the following definition of the principle: “where there are threats of serious or irreversible damage to the environment, lack of full scientific certainty should not be used as a reason for postponing cost-effective measures to prevent environmental degradation”.
This defintion gives the general direction, albeit it mainly deals with criteria for stopping destructive practices that are already in place. An effective precaution also needs to be pre-emptive, aiming to stop damage before it happens. There are many cases where precaution has been used to stop production and use of hazardous substances. In many countries, the use of PCB was banned without conclusive scientific evidence showing that the substance was causing harm. Similarly the use of ozone-depleting substances was banned prior to conclusive evidence was at hand.
If these bans had been postponed until there was such evidence, the damage would have been infinitely bigger before the substances had been phased out. But even though the substances were banned in a precautionary way, they had been used for a long time and have caused immense damages to human health and the environment as well as huge costs for society.
These disasters were possible in the first place because politicians relied on risk assessments. Pre-emptive precaution and a focus on hazard would have prevented them. The main basis for a sustainable chemicals policy must be elimination of hazardous substances through a pre-emptive precautionary approach. Ban those that exist and stop new ones before they are introduced to the market.