Which of the following is a key characteristic of a toxic exposure incident?

A key characteristic of a toxic exposure incident is an alteration in physical wellbeing. This can manifest in various ways, including symptoms such as nausea, headaches, breathing difficulties, allergic reactions, or other health issues that arise as a direct result of exposure to toxic substances. The changes in a person's physical condition indicate that the exposure has had an adverse effect on their health, distinguishing toxic exposure from scenarios where no such effects are evident.

The other choices do not adequately represent the critical characteristics of a toxic exposure incident. For instance, clear sight and normal skin temperature suggest no immediate health effects, which would not support the scenario of toxic exposure. The presence of unpleasant odors could indicate a potential hazard but does not provide concrete evidence of any physical alteration. Immediate recovery of the victim implies that the exposure was not serious enough to cause lasting harm, which would not typically describe a true toxic exposure incident. Therefore, the emphasis on alterations in physical wellbeing is essential in identifying and understanding the impact of toxic exposures.