Frozen "Mushroom Cap" Handle Traps Worker Inside Freezer Hazard Alert

Topic: Frozen "Mushroom Cap" Handle Traps Worker Inside Freezer
Date Issued: February 1, 2006 Date Revised:

An employee who was working alone at a restaurant entered a walk-in freezer. When the door closed, the employee was unable to move the “mushroom cap” handle to open the door from the inside. Three hours later, the employer found the employee unconscious. The employee sustained hypothermia and frostbite.

The freezer door could not be opened because the push rod of the mushroom-cap handle was surrounded by ice and could not be moved without significant force. The freezer door was usually open while a worker was inside, so workers rarely used the mushroom cap. It had probably taken weeks or even months for dripping water to freeze inside the handle.

Ice is more likely to build up in hot, humid weather when there is a greater difference in temperature inside and outside the freezer.

Recommended Preventive Action

  • Inspect and depress the mushroom cap release handle regularly to avoid ice buildup. Make sure the cap can move in and out easily at all times. Do this as part of your regular safety inspections.
  • Make certain employees know how the mushroom cap handle works and how to break the ice if the handle won’t move. For example, try to turn or push the knob.
  • Ensure employees understand they might need to kick the cap several times or hit it with a heavy object to break the ice inside.
  • Develop a code of practice for working alone that contains, but is not limited to:

    • Provisions for an alarm should an employee become trapped in the freezer.
    • Procedures for checking on the safety of a person working alone.
    • Emergency procedures in case someone is trapped inside the freezer.

Regulation 92-133, Code of Practice for Working Alone under the Occupational Health and Safety Act contains requirements with respect to the code of practice for working alone. Please visit for more information.

This publication was reproduced with permission from WorkSafeBC.

Reprinted April 2015

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