What is the specified Diesel withdrawal/shutdown threshold?

• A. 1.25% Shutdown
• B. 1% Withdrawn From The Area
• C. 0.5%
• D. 2%

Answer: (A)

Diesel withdrawal/shutdown threshold is about the limit at which diesel-related air contaminants in the underground environment require immediate action. Diesel exhaust adds carbon monoxide, particulates, and hydrocarbons to the air, and concentrations can create health and safety risks as well as fire/explosion hazards if allowed to rise uncontrolled. The specified limit of 1.25% means that once the diesel content in the air reaches 1.25% by volume, you must withdraw personnel from the area and shut down diesel-powered equipment there, then work to dilute the air with ventilation and restore safe conditions. This threshold is set to ensure the atmosphere stays within safe levels and to prompt timely action before concentrations become dangerous. The other percentages are not the standard trigger point for this requirement.