What degree of risk is acceptable?

Safety is a matter of how people would find risks acceptable or unacceptable,         if      they knew the risks, and are basing their judgments on their most settled value perspective.

So, to this extent, it is objective.

Perspectives differ.

To this extent, it is subjective. So, Safety is 'acceptable risk'. Acceptable Risk

‘A risk is acceptable when those affected are generally no longer (or not) apprehensive about it.’

Apprehension (i.e. anxiety) depends largely on factors such as

Whether the risk is assumed voluntarily.

How the probabilities of harm (or benefit) is perceived.

Job-related or other pressures that causes people to be aware of or to overlook risks.

Whether the defects of a risky activity or situation are immediately noticeable or close at hand.

Whether the potential victims are identifiable beforehand.