Respiratory inadequacy due to direct injury: putative agents and site of injury. The noxious agents released from the burning material can affect different parts of the airway. The cartoon indicates which part of the respiratory system is affected by each gas, toxin or chemical (“Cause”). The pathophysiological effects of each of these noxious agents are also indicated (“Effects”). Thermal or chemical injury can lead to edema of face, pharynx, glottis, and larynx. Injury to trachea and bronchi leads to bronchospasm and bronchorrhea. Chemical and toxin injury can lead to alveolar damage and pulmonary edema.