A worker appears to be improvising instead of following procedures.

The correct answer is C because the scenario strongly indicates a human factors issue related to comprehension of written information , rather than motivation or discipline.

The key observation is that the worker performs well after verbal explanation but struggles when relying solely on written procedures. This pattern repeats with new procedures, suggesting a consistent difficulty in understanding written content. CCPS highlights that human performance can be affected by factors such as literacy, language barriers, cognitive limitations, or learning styles , all of which must be considered in process safety systems.

Option A is unlikely because the worker improves immediately after explanation, indicating willingness to follow procedures once understood. Option B is also less likely because the repeated pattern suggests a systemic issue , not a one-time lack of effort.

CCPS emphasizes that procedures must be clear, accessible, and usable by the intended workforce , and organizations should account for human variability. This may include using visual aids, simplified language, hands-on training, or verbal reinforcement .

This scenario demonstrates the importance of integrating human factors engineering into process safety to ensure procedures are truly effective for all users.