HAZMAT CDL Practice Test

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Get ready for your HAZMAT CDL Test. Use multiple-choice questions and detailed explanations to solidify your understanding. Enhance your preparedness for the exam!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

Practice this question and more.

Should you turn off the engine before or after unhooking hoses during the delivery of compressed gas?

Before unhooking hoses
After unhooking hoses
It doesn't matter
Only if there is a safety hazard

The correct answer is: Before unhooking hoses

Turning off the engine before unhooking hoses during the delivery of compressed gas is essential for safety. When the engine is running, it is possible that vibrations and heat could lead to an accidental ignition of flammable gases, or exacerbate any leaks that might be present in the hoses. Additionally, shutting off the engine eliminates sources of ignition and reduces the risk of an explosion or fire in the event of an unexpected gas release. This practice reflects standard safety protocols in handling hazardous materials. It helps ensure a safe environment for both the operator and those nearby by minimizing potential hazards associated with combustible gases being released or ignited inadvertently. Taking this precaution is particularly important when working with materials that are known to be volatile or flammable, as is common with many compressed gases.