collision of a CGH2 trailer

A CGH2 trailer lost control and left the road travelling for approximately 65 feet before rolling approximately one quarter times. After which it impacted a fence and a utility pole and came to rest on the roadside.
Local fire and police were dispatched and secured the scene and maintained initial isolation distance according to the emergency response guidebook. Also the emergency response team of the company arrived on and checked the condition of the trailer, looking for leaks. They identified "bubbler" type neck leaks on two tubes. “Bubbler” indicates that lead detection fluid bubbled continuously but not rapidly (approximately 1 cc/10 sec). The leaks continued for approximately 3 hours.
An hydrogen detector was placed above the leaks to determine atmospheric hazards due to the flammability of hydrogen. The detector never exceeded 7% of the low flammability limit (LEL). The emergency teams decided to transfer the contents of the two leaking tubes to an empty hydrogen tube trailer. Once complete, the company team checked the tubes for leaks again and found none. The LEL in the atmosphere had dropped to 0% of LEL.

The tractor and trailer was up-righted by a crane and towed back to the company home terminal.

INITIATING CAUSE was a traffic accident.
The ROOT CAUSE was an error of the driver.

CH2 tube neck

DESCRIPTION OF THE UNIT
The trailer consisted of 10 tubes.
The PHMSA source provides a amount of released hydrogen of 10 GCF, which results in a negligible quantity of few tens of grams.
The capacity is not provided, but it could be assumed that it ranges from 300 to 400 kg.

The emergency team worked to identify the location and the intensity of the leak(s), using the soap method and a hydrogen LEL detector. After which, they proceeded to transfer the hydrogen in the leaking tubes to a second, empty trailer.

This is a case of a small leak, by which the leaking hydrogen cannot form a flammable mixture in air. For this reason, the emergency team could proceed to the transfer of the hydrogen from the leaking tubes to another trailer. In the case of greater leaks, the better strategy would be to let the hydrogen venting, keeping at safe distance the emergency teams

The only recommendation that could be offered is continued training on roadway awareness. The evaluation of the incident found an improper use of lanes by the driver. The roadway was narrow in nature but not unsafe. There should have been no reason to drive as close as this driver did to right part of the roadway. The driver stated he was aware of the bar ditch on either side of the roadway but probably did not take into account the softness of the ground
just off of the asphalt.