Which factor may increase risks during nighttime operations in a maintenance setting?

Fatigue among employees is a critical factor that can substantially increase risks during nighttime operations in a maintenance setting. During night shifts, workers are more prone to experiencing fatigue due to the body's natural circadian rhythms, which can lead to decreased alertness, impaired judgment, and slower reaction times. Fatigue can significantly impact a worker's performance, increasing the likelihood of accidents and errors in maintenance tasks, which may involve operating machinery or working in hazardous environments.

In comparison, options such as better lighting, increased worker alertness, and higher temperatures do not contribute to heightened risks in the same way. While better lighting may actually reduce risks by improving visibility and safety, increased worker alertness is beneficial, as it helps in maintaining focus and responding effectively to potential hazards. Higher temperatures could lead to heat-related illnesses, but they do not have the same direct impact on cognitive functions and reaction times as fatigue does. Therefore, fatigue stands out as a major risk factor specifically affecting safety margins and operational effectiveness during nighttime work.