In these fields, the requirement is often driven by internal agency policy or "Fitness for Duty" (FFD) regulations rather than a single federal law.
- Nuclear Power Plant Operators: The Nuclear Regulatory Commission (NRC) requires operators to be "fit for duty." Medical exams for these roles often screen for any condition that could lead to sudden sleepiness while monitoring reactors.
- Law Enforcement & Firefighters: Some departments require sleep screening as part of their comprehensive physicals, especially for specialized units (like SWAT) where split-second alertness is non-negotiable.
- Commercial Divers: Because falling asleep or losing focus underwater is fatal, divers must pass rigorous physicals that often include screening for respiratory or sleep issues.
