In early afternoon, a northbound tractor-semitrailer with horizontally mounted tubes filled with compressed hydrogen at approximately 2400 psi (166 bar) was struck by a northbound pickup truck that veered into the semitrailer's right rear axle. According to witnesses, the tractor-semitrailer then went out of control and left the roadway, coming to rest approximately 300 feet (91 meters) from the point of impact. As a result of rotational torque and impact, the end of one tube was sheared off at the bulkhead and left the tube bundle. During the process, some of the tubes, valves, piping, and fittings at the rear of the semitrailer were damaged and released hydrogen. The hydrogen ignited and burned the rear of the semitrailer. In the meantime, the pickup truck had also run off the road and its fuel line ruptured, resulting in the truck being destroyed by fire.
The tractor-semitrailer driver was killed as a result of blunt force trauma. The driver of the pickup truck received non-life-threatening injuries. Residents of five homes in the vicinity of the accident were asked to evacuate, and the highway was closed for more than 12 hours. Damage, cleanup, and lost revenues were estimated at $155,000.
Numerous emergency personnel responded to the accident. First responders on the scene were volunteer fireman and initially positioned themselves in direct line with the forward ends of the hydrogen tubes to put out the fire and extricate the truck driver. When the HazMat team arrived, they decided to take a more defensive position away from a direct line with the forward ends of the hydrogen tubes and concentrate on cooling the tubes from a safe distance. An emergency response team associated with the hydrogen carrier responded with the equipment necessary to flare the residual pressure in the tubes. Approximately four hours after the accident occurred, the local fire personnel demobilized and departed. Approximately 10 hours from the time of the accident, all tubes had been vented of hydrogen and the fire was out.
1. Increase physical protection, shielding, and securing of transported hydrogen tube valves, piping, and fittings from multi-directional forces that are likely to occur during accidents, including rollovers. Reference: 49 Code of Federal Regulations [CFR] 173.301.
2. Provide training to emergency responders on the unique chemical and flammability properties of hydrogen, including its nearly invisible flame during daylight hours and its tendency to rise quickly since it is 14 times lighter than air.