What Happened
Small amounts of residual sodium metal (Na) on lab spatulas and tools were quenched by placing the items in an isopropanol bath within a fume hood. Not all tools were fully submerged in the solvent bath, and the reaction was not stirred. Water was then added to the isopropanol bath.
Unreacted sodium remained on the tools and reacted upon contact with the water, igniting a fire. The heat from the fire damaged the fume hood sash and caused melting of nearby containers.
What went right?
- The lab immediately called 911.
- The fume hood sash was kept closed, helping to contain the fire and heat.
- Laboratory occupants evacuated the space & the fire alarm was pulled to notify other building occupants.
- The lab members were wearing appropriate PPE (flame-resistant lab coat, safety glasses, gloves)
- The researchers worked in a team during the quenching to ensure no one works alone.
- The researcher provided a summary of the incident and shared details with EH&S during a follow-up.
What should have been done differently?
- Quenching of water reactive materials should have been performed using a slow, controlled, and continuously stirred approach, with confirmation that reactivity had fully ceased before progressing to more reactive quenching steps.
- Quenching should proceed in a step-wise order of increasing reactivity: isopropanol, followed by methanol, and then water.
- All sodium-contaminated tools should have been fully submerged in the solvent bath.
- Researchers should have removed all flammable and combustible materials from the fume hood prior to quenching.
What corrective actions will be taken?
- The incident was discussed with the lab and the SOP has been updated and reviewed by appropriate lab members.
- In the future, quenching of water reactive materials will be performed slowly, under continuous stirring, and with unnecessary materials removed from the work area.
Lessons Learned
Improper quenching of water-reactive materials can result in fires, highlighting the need for slow, controlled, and continuously stirred quenching procedures. This incident emphasizes the importance of appropriate training and reviewing applicable SOPs before performing reactive work.
