Safety is the state of being "safe" (from French sauf), the condition of being protected from harm or other non-desirable outcomes. Safety can also refer to the control of recognized hazards in order to achieve an acceptable level of risk.
A man wants no protection when his conduct is strictly right.
William Murray, 1st Earl of Mansfield, Bird v. Gunston (1785), 3 Doug. 275; reported in James William Norton-Kyshe, Dictionary of Legal Quotations (1904), p. 212.
Cancer risk in humans exposed to low radiation doses is usually calculated based upon estimates obtained at higher doses. As many cancers originate in stem cells, studying low dose radiation effects on these cells is particularly important.