CDL Hazardous Materials Endorsement (HME)Emergencies and AccidentsEasy
A driver is transporting a shipment of Class 2.2 Non-Flammable, Non-Poisonous Gas (e.g., compressed air, UN1002) in cylinders. During an inspection, the driver notices a small leak from one of the cylinder valves, creating an audible hiss but no visible cloud. What is the most appropriate immediate action?
- AContinuously monitor the leak and proceed to the nearest repair facility.
- BTighten the valve, ensure proper ventilation, and continue the route if the leak stops.
- CAttempt to seal the leak using a temporary patch or tape.
- DMove the leaking cylinder to an isolated area away from the vehicle and other cargo.
Show answer & explanationAnswer & explanation
Correct answer: B. Tighten the valve, ensure proper ventilation, and continue the route if the leak stops.
For a small, non-flammable, non-poisonous gas leak from a valve, the first step is often to attempt to stop the leak by tightening the valve. Ensuring ventilation is also crucial. If the leak stops, the driver can continue, but should monitor it.
Why the other options are wrong
- A. Monitoring without attempting to stop the leak is not sufficient; the leak should be addressed first.
- C. Temporary patches or tape are generally ineffective and unsafe for pressurized gas leaks.
- D. Moving a leaking pressurized cylinder can be dangerous and is not the first step when a simple valve tightening might resolve the issue for a non-hazardous gas.
Non-Flammable Gas Leak Response
For a small leak from a cylinder valve of a non-flammable, non-poisonous gas, the immediate action is often to attempt to tighten the valve and ensure good ventilation. If the leak persists, further action is needed.
- Identify the type of gas (non-flammable, non-poisonous).
- Attempt to stop the leak at the source (e.g., tighten valve).
- Ensure ventilation.
- If leak persists, follow emergency procedures.
Memory trick: Hissing valve, just give it a twist, then watch the air flow, no need to be missed!