What may hinder an investigator's ability to respond effectively during a Toxic Gas incident?

During a Toxic Gas incident, visibility issues caused by gas are particularly detrimental to an investigator's ability to respond effectively. When toxic gases are released, they can create a dense cloud that obscures vision, making it difficult for responders to navigate the area, assess the situation, and identify potential victims or sources of the gas. The lack of visibility can also impede the investigator’s ability to reach critical locations quickly and safely, thus delaying any required interventions.

In contrast, while excessive training requirements, inaccessibility of gas detection equipment, and complicated evacuation plans can pose challenges, they do not directly affect the immediate physical environment and visibility as much as the presence of gas. Visibility issues stem from the characteristics of the toxic gas itself, thus making it a unique and significant obstacle during such incidents.