Last Revised: April 12, 2024

Issue Date 3/2021


Hazard Description

Heating agarose in the microwave, while a common laboratory procedure, can result in injury if proper precautions are not taken.  Agarose can become superheated and boil suddenly when removed from the microwave, resulting in splash or burn injuries to the hands, arms, and face.  This Fact Sheet provides some basic guidance for appropriate handling of hot agarose.


PPE Requirements

Wear standard personal protective equipment (gloves, lab coat and safety glasses) at all times.  Heat-resistant gloves are recommended for handling hot glassware.  For more information, see Lab Coat, Gloves, and Safety Eyewear Policy and Fact Sheet: Heating Reactions.


Recommendations for Microwave Heating

  • Consider using a flask that is 2-4 times the volume of the solution when preparing the agarose to leave room for boiling and expansion.
  • Lightly cover the top of the flask with a paper towel or microwave safe plastic wrap that is vented. 
  • Microwave one flask at a time; doing two flasks at once can take more than twice as long, and there’s a possibility that one flask will boil over before the other is fully melted.
  • Monitor the flask at all times while heating in the microwave.
  • Use shorter bursts of heating for better monitoring.  Stop the microwave to swirl (not shake) the flask when the agarose starts to bubble.
  • Use heat-resistant gloves to protect your hands when handling the flask containing hot agarose.


Related Fact Sheets and SOPs

  1. Lab Coat, Gloves, and Safety Eyewear Policy:
  2. Fact Sheet: Heating Reactions:



  1. Preparation of Agarose Gels:
  2. DNA Electrophoresis Method:
  3. Biotech Basics: Avoiding Agarose Microwave Explosions:
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