A Hacker News thread discusses the "Swiss Cheese" Failure Model, a safety concept where multiple layers of defense (like slices of Swiss cheese) have holes, and disaster occurs when those holes align. The original link was criticized for poor quality, with Wikipedia offered as a better resource. Commenters highlighted the model's relevance, citing Chernobyl as a classic example of multiple failures leading to catastrophe. Redundant safety systems are designed to counteract inevitable "holes" in each layer, but complexity can obscure these flaws. The discussion highlights the importance of "defense in depth" and the potential for seemingly minor mitigations to be crucial. Nuclear power and aviation safety widely utilize the model, with NASA's ASRS system (analyzing near-miss events) offered as a practical example. The conversation also touches on the idea that catastrophes often result from a series of compounding failures, making the "obvious" cause only the final trigger.