Which of the following complaints may indicate a need to report a chemical exposure?

The presence of headaches and fatigue can be indicative of a chemical exposure, particularly if these symptoms arise suddenly or are out of the ordinary for that individual. Chemical exposure can impact the nervous system and other bodily functions, leading to such nonspecific symptoms as headaches, drowsiness, or general fatigue. These signs may suggest that the body is reacting negatively to a toxic substance or irritant, thereby warranting a report to ensure proper investigation and response to the potential hazard.

Other options, while possibly relevant to different health concerns, do not directly suggest chemical exposure in the same way. For example, feeling thirsty often might indicate dehydration, frequent yawning could relate to tiredness or boredom, and skin dryness is typically associated with environmental factors or dermatological issues rather than chemical toxicity. Therefore, headaches and fatigue are more closely associated with the effects of chemical exposure, making this choice the most appropriate in this context.