CGH2 trailer collision

A tube trailer-tractor was traveling on a highway, left the road into the median, striking a guardrail and then overturning. As a consequence, a tube valve cracked at the stem resulting in a slow release of hydrogen from one tube on the trailer. All tube valves and manifold valves were closed.
As a precaution, emergency crews evacuated the immediate area. A team from the trailer company was dispatched to the scene. Before up-righting the trailer, they vented the remaining hydrogen through the vent stack and purged the tubes with nitrogen. There was no fire.

INITIATING CAUSE was a traffic accident.
In absence of information on driver, the ROOT CAUSE is attributed generically to a human error (wrong manoeuvre).

Valve stem

The driver was light injured.
60 to 70 people were evacuated.
Material Loss: $4,320.00
Carrier Damage: $150,000.00
Property Damage: $0.00
Response Cost: $15,000.00
Remediation/Cleanup Cost: $30,000.00

Road incidents, such as crash and loss of control of vehicles during driving are unavoidable initiating causes.
The transport company believed difficult to identify additional improvements to structures and packaging able to face impact forces typical of severe incidents like this one. In this case, the design safety features definitively impeded large and rapid confinement losses, and the break at the valve stem caused only a slow release which dispersed before formation of a possible flammable mixture. However, there are other similar impacts which brought to higher hydrogen releases and ignition