What defines a poisonous gas under Class 2?

A poisonous gas under Class 2 is defined as toxic at low concentrations. This means that even a small amount of the gas can pose a significant health risk through inhalation or other forms of exposure. The classification emphasizes the need for caution when handling or being near these substances, as they can have detrimental effects on human health even in minimal amounts. Understanding this characteristic is crucial for first responders, as it influences the safety measures and protocols necessary to manage incidents involving such gases effectively. The focus is on the potential danger posed by the substance and the immediate need for appropriate protective measures to mitigate exposure risk.