Chemical Waste Container Explosion – Lessons Learned


EH&S staff were notified of a chemical spill on August 2, 2017, during which a waste bottle ruptured in secondary containment bin, spilling about 3 liters of liquid. The lab was evacuated and a hazardous material team cleaned up the chemicals and shattered glass.

The ruptured 4 liter glass bottle was manufactured for chemical waste storage and disposal purposes, and reportedly contained a mixture of organic solvents. EH&S staff noted that the hazardous waste label was incomplete and the actual contents were unknown.

The bottle was approximately 80% full with 1.5” of headspace at the top of the bottle. The cap was on tight. Temperatures in the lab were above 80 degrees due to a cooling system failure in the building. EH&S does not believe that the elevated temperature alone was a root cause of this incident. Inadequate headspace or the mixing of incompatible waste streams may have led to over-pressurization and the rupture of the waste bottle.

Chemical waste bottle

EH&S staff also noted that they had not received a request from the lab to collect and dispose of the contents of this bottle, despite being overfilled with hazardous waste.

This event highlights some key guidelines to follow for hazardous waste accumulation.

  • Don’t place incompatible chemicals together in a waste bottle.
  • Use appropriate containers that are compatible with the contents.
  • Label your waste containers before you begin using them with a UW Hazardous Waste Label.
  • Waste containers should remain closed at all times except when adding waste.
  • Don’t overfill waste containers. Bottles should be no more than ¾ full to allow for vapor headspace and prevent over-pressurization accidents.
  • Request hazardous waste collections as soon as the container is ¾ full.
  • Use secondary containment bins if waste containers are stored on the floor.

For more information on best practices for hazardous chemical waste, refer to Section 3 of your Laboratory Safety Manual.