A 30-milliliter (mL) vacuum bulb, equipped with a glass stopcock, containing one gram of pentacarbonyl manganese hydride exploded in a refrigerator. This caused the breakage of three other containers, releasing some contents into the refrigerator. The chemicals did not react. The refrigerator contained numerous reactive and flammable chemicals, mostly in glass containers.
The damaged containers were removed and relocated under a hood. The refrigerator was then examined for other breakage and inventoried. All breakage was cleaned up. The safety coordinator was notified and began an investigation.
The direct cause of the occurrence was the failure of a glass vacuum bulb, which either fractured due to some unforeseen chemical reaction forming hydrogen gas, or was unable to resist some pressure buildup. The root cause is also attributable to the materials, either the chemical, or the vacuum bulb. The fact that refrigerators are commonly used throughout to store a variety of chemicals is not unique. However, this occurrence could have been much more severe if incompatible chemicals were involved.
In the future, the laboratory will issue a memorandum about this incident to illustrate the need to wear safety glasses with side shields, store chemicals compatibly, take care when placing chemicals in the refrigerators for storage, and keep the quantities minimal. The laboratory will issue guidance regarding chemical storage hazards, identifying the hazard and requiring all chemicals to be stored according to compatibility, with secondary containment provided, in approved refrigerators.
The main point to keep in mind is to minimize the quantities of reactive materials to be stored in refrigerators. Chemicals placed in refrigerators should be stored with regard to their chemical compatibility, and secondary containment should be provided to prevent contact with incompatible chemicals.
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.