A small research sample of approximately 5 grams of aluminum hydride (alane) doped with 2-3 mol % TiCl3 contained within a glass ampoule ruptured after transit while stored in an office cabinet. The rupture was attributed to over-pressurization caused by hydrogen gas buildup within the sample over a four-month period. The glass ampoule, contained within a 0.2-inch thick cardboard shipping tube, was not a pressure-rated container. The rupture resulted in glass chards penetrating the protective cardboard shipping tube. The aluminum hydride, a fine powder, was released from the shipping tube during the pressure release. The fine aluminum powder leaked from the cabinet and set off a local smoke alarm that brought emergency responders to the scene. No personnel were present in the area when the incident occurred at almost midnight. Inspection of the packaging after the incident did not show evidence of any fire or smoke associated with the glass ampoule rupture. No injures occurred related to the rupture.
If this incident had happened during transit, personnel injury and damage to surrounding material could have occurred. Similar injury and damage could have occurred at the receiver facility during transit, storage, or preparing for analysis.
- Laboratory Equipment
1. All samples with potential for hydrogen buildup should be limited to ground shipment only. (This shipment was by ground and air. If this incident were to have happened in an airplane, the consequences may have been worse.)
2. All samples must be properly labeled before shipping. Hazard label warnings need to be located on the outside of the shipment package.
3. The following safety information should be included with the shipment: the material safety data sheet (MSDS), applicable standard operating procedures (SOPs), and detailed information for the safe handling of the materials.
4. Improper labeling can result in improper handling and storage. Lack of proper labels allowed the sample to be delivered to an office rather than a laboratory, where the material can be properly handled and stored in an approved location.
5. For hazardous material shipments, do not ship material in quantities beyond what is needed by the receiver. Lesser material quantities lead to reduced risks in the event of a failure. In this incident, the analysis only required 0.1-0.2 gram of material, but 5 grams of the material were shipped. The receiver suggests that future sample sizes for this analysis be limited to a maximum of 0.5 gram (10% of what was shipped in this incident).
6. Samples that have the potential for hydrogen generation should use a pressure-rated container with the following features:
a. Head space to contain the maximum possible gas release from the sample below the container's maximum safety pressure limit.
b. Pressure relief mechanism (such as a release valve) that can be slowly opened within a glove box to safely equalize any pressure build-up.
c. Outer shell capable of containing any flying debris. A secondary metal container outside the pressure-rated container is suggested as a possible solution for containing potential flying debris.
7. Sealed glass containers should not be used to store samples that could generate pressure over time. These types of glass containers are not rated for pressure. Capped glass vials, bottles, or metal cans are alternate options to consider.
8. Safe transport and handling procedures for these types of materials need to be followed. The receiver requested that all shipments from the shipper of this sample be stopped until safety concerns from this incident are addressed.
9. Store these types of materials in proper approved storage. MSDSs should be available either locally or at a central location.
10. If a sample shipment lacks proper documentation, treat it as potentially hazardous until proper documentation is obtained.
11. DO NOT become comfortable with handling these types of aluminum hydride materials. Routine handling of these samples without problems can lull users into shortcuts that could result in more damaging results than this incident. If this incident had happened with personnel present, there was a potential for personnel injury.
Additional discussion about working with reactive metal-hydride materials in the laboratory can be found in the Lessons Learned Corner on this website and in the Hydrogen Safety Best Practices Manual.