Unattended process leads to building evacuation.

Updated February 19, 2015

Incident or near miss – Brief description

Researcher passing through a campus building hallway on a Saturday afternoon smelled a burning odor coming from a lab.  After knocking on the door and getting no answer, he proceeded to leave building, activating fire alarm.  When the fire department arrived, they found a hot plate/stirrer with a scorched beaker on top out on an open lab bench.  They turned off the hot plate and allowed people back into the building, but not into the lab until EHS verified it was safe.


Response action – EHS on-call person came in and noticed an odor like burnt marshmallows in the hallway outside the lab.  After entering the lab, with the assistance of a lab member who had been waiting to get in, the air was sampled for VOCs and carbon monoxide with nothing detected.  The area was inspected, and the beaker on the hot plate was moved to a lab hood to reduce the odor. The campus policeman stationed outside was notified it was O.K. to leave and allow persons to re-enter the lab.

There was no information about the unattended process.  It was observed that there was a squirt bottle of acetone and a 4L bottle of acetonitrile in the vicinity of the hot plate, and a satellite accumulation area nearby. However, any fire that resulted appeared to have been confined to the beaker and hot plate.


Immediate Cause – contributing cause(s)

There was an unattended off-hours process on a lab bench top with what turned out to be a malfunctioning hot-plate.  The hot plate was set for 30C (85F) to make a lactose solution, which takes a long time to dissolve, according to the researcher involved.

There was no information or sign about the unattended process, materials involved and who to contact if there was a problem.   


Recommended corrective action(s) or lessons learned –

  1. Take care when setting up an unattended process.  Ideally, such processes should be set up in a safe place, such as a fume hood without other items in it, or a well cleared bench-top space for low hazard operations.
  2. Provide signage about the process, materials involved, and who to call if there is a problem.  These signs should be posted on the lab door and by the process.
  3. Make sure equipment is functioning appropriately before leaving it unattended, or select equipment that has automatic shut off features so process will not overheat. (note:  It was recommended the malfunctioning hot plate be taken out of service.)


What worked well – The response of the individual who noticed the odor and took action to activate the fire alarm was excellent.    Assistance with lab entry and the investigation provided by the lab member was helpful.