The chemical and physical properties of liquids may change when gases are dissolved in solution. Supplier MSDSs may lack precautionary information addressing the hazards associated with gases dissolved in solution. This incident reinforces the importance of understanding the properties of chemicals before acquisition, use and storage.
Effects of Incident
The incident was an injury free event that could have resulted in shrapnel wounds from glass projectiles, and eye / skin contact with a chemical solution.
During a routine chemical inventory, containers stored in a small refrigerator rated for flammable storage were inspected and scanned with a barcode reader.
An original factory 800 mL glass bottle containing 1,4-dioxane with 0.5 M ammonia dissolved in solution was taken out of the refrigerator, and set on a lab bench top temporarily to affix a barcode and collect the specific information needed from its label. Approximately 1-2 minutes after the container was set on the bench top, it burst. The glass bottle was under enough pressure to cause it to burst into 4 large sections, scattering three of them across the lab bench top. The bottom section of the bottle remained in place and was still "holding" the frozen (but now melting) contents. Fortunately, no injuries or damage were caused and proper response / clean-up procedures were followed after the incident.
The incident investigation revealed that the container as received from the chemical supplier had been unopened. The outer cap had been sealed and the inner Sure-Seal cap had been in place. Furthermore it was determined that neither the container label nor the MSDS had explicit warnings about the refrigeration hazard. However, the label did state that the solution contained a 0.5 M concentration of dissolved ammonia gas. Further investigation revealed that 1,4-dioxane freezes at 10-12 degrees C. When ammonia is added to 1,4-dioxane, and the solution is allowed to freeze / thaw, pressure is generated inside the container due to the ammonia coming out of the solution.
Corrective Actions to Prevent Reoccurrence
Do not store 1,4-dioxane containing ammonia in a refrigerator. This chemical should be consigned to a flammable storage cabinet at room temperature.
The chemical supplier was contacted regarding the incident and the lack of specific precautionary information in the MSDS.
Seek assistance as needed from site industrial hygiene professionals.