Final answer:
The duty owed and the line of responsibility in legal terms depend on the concepts of foreseeability and causation. A person owes a duty to those who could reasonably be harmed by their actions if they were aware of the danger. Responsibility for downstream consequences is determined by the concept of proximate cause, with a limit to how far the responsibility extends.
Step-by-step explanation:
In legal terms, who a person owes a duty to and when a person should stop being responsible for the consequences of their actions depends on the concept of causation and foreseeability.
Regarding the duty owed, it is generally determined by whether a person could have reasonably foreseen the harm that resulted from their actions. For example, in the case of the railroad employee who unknowingly handles a package containing explosives, they owe a duty to anyone who could be harmed by their actions if they were aware of the danger. In this case, the employee would owe a duty to anyone who could be harmed by an explosion caused by mishandling of the package.
Concerning the responsibility for downstream consequences, the concept of proximate cause is applied. Proximate cause refers to the idea that a person is responsible for the consequences of their actions that are reasonably foreseeable. However, there is a limit to how far the responsibility extends. The line is drawn when the consequences become too remote or unforeseeable from the original action. In the example of dropping a lit match at a gas station, causing an explosion that triggers a heart attack in an elderly man blocks away, it may be argued that the consequences are too remote and unforeseeable.
Ultimately, determining the duty owed and the line of responsibility is a matter of law and involves considering factors such as foreseeability, proximate cause, and the concept of reasonable care.