looking outside of the UK there are health and safety legal systems operating worldwide. Many of these follow the international labour organisation model which requires employers to protect both workers and the public so far as is reasonably practicable.
"Reasonably practicable" means that when deciding what to do to protect workers and others such as visitors,employers will be expected to do all that is possible or technically feasible to adequately control the risk, based on local or national legislative principles . Employers can balance the health and safety risk of an activity against the cost (in terms of money, time or effort needed) of controlling this risk. here, for protection to be "reasonably practicable" the risk and the cost should be balanced,therefore a high risk might require more resources to adequately control it than would a low risk.