A guest student was weighing out less than 200 mg of sodium hydride. The material reacted with moisture in the air, producing hydrogen. The heat of the reaction ignited the hydrogen on the end of the spatula being used to transfer the material and at the mouth of the bag holding the stock material (approximately 48 to 50 g). The student attempted to smother the flames with a cotton lab coat hanging nearby. He quickly determined that the lab coat was insufficient to smother the flames and entered the adjoining lab to get a fire extinguisher and warn other lab workers in the area. The other lab workers exited the lab, warned others in the area, pulled the fire alarm and called the laboratory shift supervisor. The student extinguished the fire with the fire extinguisher, then left the building with the other occupants.
Members of the onsite fire department responded and entered the building at 16:04. They noted the absence of smoke in the hallways, dissipating smoke in the lab and no apparent flames. The Hazardous Materials Response Team was assembled to develop a plan for mitigation. Building occupants were escorted back into the building to power down critical experiments and at 18:00 all occupants were given the opportunity to re-enter the building to collect personal items and leave for the day. At 19:20, the Hazardous Materials Response Team entered the laboratory to execute the mitigation plan, removing the materials from the area and wiping down the area with mineral oil. There were no injuries resulting from this event.
- Process Equipment
- Sodium Hydride Container
Some hydride materials (e.g., sodium alanates) may be rapidly exothermic, even pyrophoric, if exposed to water or humid air or slowly exothermic, even pyrophoric, if exposed to oxygen. Reactive materials, including fine metal powders, should be handled (as in this incident) in an inert atmosphere such as a glove box. The protocol for handling these materials should be incorporated into a standard operating procedure and appropriate safety training conducted for laboratory personnel, including guest staff.
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.