Safety-critical items are parts, assemblies, materials, characteristics, software outputs, or process results whose failure, nonconformance, or incorrect use could create an unacceptable product safety risk. In manufacturing, the term is commonly used to identify items that require defined controls because their condition can affect safe product performance.
Safety-critical items may be identified through design requirements, customer flow-downs, risk analysis, regulatory obligations, product safety planning, or quality management processes such as those used in AS9100 environments. Typical controls may include controlled work instructions, inspection points, traceability, special handling, configuration control, approval steps, and tighter nonconformance disposition. The specific controls depend on the product, process, and applicable requirements.
The term should not be confused with general workplace safety supplies or with every high-value or hard-to-replace component. It also differs from a key characteristic, which is usually a feature with significant impact on fit, form, function, performance, or producibility. A key characteristic can be safety-critical, but the terms are not automatically equivalent.