What is a common indicator of hazardous material exposure?

Increased heart rate is a common indicator of hazardous material exposure because it reflects the body's physiological response to stress or danger. When an individual is exposed to hazardous substances, the body may react in a manner akin to a fight-or-flight response, which can lead to an increase in heart rate. This response is part of the autonomic nervous system's regulation, attempting to prepare the body to deal with the perceived threat.

Other indicators of hazardous material exposure can include symptoms such as difficulty breathing, dizziness, and skin irritation, among others. Increased heart rate is particularly relevant in the context of chemical exposure, as certain toxins can stimulate the cardiovascular system directly or indirectly lead to stress responses.

In contrast, the other choices do not typically correlate strongly with hazardous material exposure. Bright skin color may be a sign of various health conditions but is not specifically tied to hazardous material exposure. Rapid weight gain is unlikely to be an immediate response to exposure; instead, it indicates a longer-term health issue. Decreased blood pressure can occur due to medical conditions or shock but isn't commonly associated with acute hazardous material exposure. Thus, increased heart rate stands out as a clear and immediate physiological reaction to such situations.