For the purposes of this SciPoll, we focus on setting safe exposure limits for chemicals. We will assume that the precautionary principle means setting very low (maybe the lowest scientifically defensible) safe exposure limits. We will also assume that best available science would result in a much higher safe exposure limit (less stringent). Where on this continuum do you think policy makers should follow the weight of scientific evidence given the following varying levels of confidence (select one).

Decisions makers should work on the basis of scientific evidence

Lack of scientific evidence does not always mean that a specific practice (whether deciding on exposure limits or interventions) is wrong. There are anecdotal evidences and gutfeel that sometimes also informs the way we decide. By being lean with the precautionary measures, we ensure that we keep exposure to a limit of what is known while also providing a slight opening to understand the situation. The latter is essential in developing a growing understanding of the problem at hand.

Definitely, if the evidence is conclusive, it best to base decision making on the scientific evidence that is available.

Evidence base helps us to learn and confirm

Since the precautionary principle means setting very low safe exposure limits, policymakers should prioritize protecting public health and the environment, even when scientific evidence may not be definitive or conclusive. This approach emphasizes erring caution to minimize potential risks and prioritize the well-being of communities and ecosystems. Besides, the precautionary principle recognizes that in situations with scientific uncertainty, it is preferable to adopt preventive measures rather than wait for conclusive evidence of harm. By setting stringent safe exposure limits based on the lowest scientifically defensible thresholds, policymakers can prioritize the potential risks associated with chemicals and protecting human health and the environment.
However, it is essential to note that applying the precautionary principle may vary across jurisdictions and specific circumstances. The interpretation and implementation of the principle can be influenced by a range of factors, including legal frameworks, risk assessments, stakeholder involvement, and societal values.

Not having sufficient evidence and using it as a confidence factor can lead to large-scale harm in populations. There is no justification for not pursuing that.

If a person knows how dangerous a chemical be, he can take precautionary measures accordingly, otherwise take suggestions from scientific literature of good journals to see the precautionary measures to be taken.

Safe exposure limits should ideally be lead by reliable data. In some cases, where data is lacking, it makes sense to introduce limited extrapolation (class effects, read across, etc.) as part of the assessment, add additional uncertainty factors, etc. The correct amount of acceptable risk is always heavily influenced and determined by the societal expectations and mores around safety in various scenarios (occupational, environmental, food, etc), which means that the appropriate amount to weight precaution in government assessments will vary by region to region, and decade to decade as social expectations change.

The scientific evidence should always be the reason to create this kind of politics

The scientific evidence of high confidence needs fewer/no precautionary measures.

Low exposure of harmful chemicals should be necessary for safe use. Safe limits are important in dealing with every new chemical or whose effect is concluded yet by any scientific means. Then, people should avoid using or use the chemical with caution.

When deciding thresholds for safe exposure to chemicals, chemicals with unknown effects should always be handled carefully

Scientific evidence must be evaluated if science is to be used to predict causation. The ability to detect low concentrations of chemicals has progressed faster than the accumultion of the effects of very low concentrations of these chemicals.

Let's be safe first and foremost

decisions will always have uncertainty, so analysis should always consider both uncertain risks and unintended consequences

If no data are available, there are no data upon which to build a weight of evidence approach. With some data of medium and low confidence, a balance of precautionary methods and weight of evidence considerations seem reasonable. With high confidence in a body of evidence (even if no effect), a weight of evidence approach can be applied without bringing in precautionary principles.

Strange question, because my answers depend crucially on the costs of being TOO precautionary-- but in the absence of any mention of this, I'll assume (based on experience) that the costs of control will be exaggerated MORE hysterically than the risks ever are!

Precaution should be exercised in the absence of scientific evidence.

The precautionary approach and learning is needed to imbibe amongst all

Better safe than sorry. Not using a precautionary approach unnecessarily puts public health at risk.