The need for a graded response to environmental risks, including the need to extend medical surveillance, for which screening is one tool, to populations at high risk of occupation-ally attributable disease is discussed from ethical, social, and biological perspectives. Ethical judgments need to be understood in terms of their derivation and implications in the form of rights or criteria for moral management of such populations. These rights must be exercised in an appropriate social context enabling the right-to-know and notification. Discussion of the biological perspective heuristically is conducted in terms of “population thinking. ” Critical methodologie problems emanate from this approach that impact on deterministic orientations in the interpretation of individual surveillance data. Nelson's concept of “added burden of risk” is seen as a valid postulate for management of populations at risk.