Which two strategies are generally considered the most robust and reliable in inherently safer design?

Inherently safer design focuses on reducing hazards at the source rather than managing them after they have been created. The most robust and reliable strategies in inherently safer design emphasize making the process safer by eliminating or significantly reducing the potential for incidents, rather than relying on controls and procedures to manage those risks.

The inherent strategy is about designing processes and systems that are less hazardous by nature. This can involve selecting materials that are less toxic or implementing processes that do not produce hazardous byproducts. By fundamentally altering the design at the outset, the potential for accidents is minimized.

Passive strategies enhance safety through built-in features that inherently reduce risks without the need for human intervention or external controls. This can include using designs that naturally contain hazardous materials or applying gravity to facilitate safe process flows (e.g., using spill containment effectively).

Together, inherent and passive strategies offer a powerful combination for improving safety. They focus on removing or minimizing hazards and reliance on external controls, making them more reliable and robust in promoting safety across various processes. This alignment with the principles of inherently safer design makes this combination the most appropriate answer.