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ES&H Manual
Chapter 6550 Cryogenic Safety Program

Work with cryogenic material, where release is possible, is considered a Risk Code 3 by Jefferson Lab. Therefore, an Operational Safety Procedure (OSP) may be required in accordance with ES&H Manual Chapter 3210 Work Planning, Control, and Authorization Process.

Jefferson Lab utilizes super-cooled gases (otherwise known as cryogens) to support superconducting radio frequency cavities and magnets at extremely low (cryogenic) temperatures (below -150°C, -238°F, or 123 K).
    Cryogens present the following hazards:
  • Extreme cold including immediate tissue destruction, and
  • Oxygen Deficiency Hazard (ODH)
This program satisfies applicable federal, state, and local requirements as outlined in ES&H Manual Chapter 2410 Appendix T1 Hazard Issues List.

This document describes responsibilities and expectations associated with the following cryogens used at Jefferson Lab:
  • helium
  • nitrogen
  • argon
  • hydrogen
  • oxygen
Liquid air is not used in significant quantities at Jefferson Lab, but can be produced as an unwanted by-product by the interaction of air with the surface of exposed piping colder than 80° K. A constituent of liquid air is liquid oxygen. Any contact between liquid oxygen and petroleum products must be avoided.

NOTE: The use of cryogens contributes significantly to ODH at Jefferson Lab. See ES&H Manual Chapter 6540 Oxygen Deficiency Hazard (ODH) Control Program and its associated appendices for additional information.

Table 1: Required Safety Training by Job Classification

Training Course Qualified Cryogenic Worker


T1 Required Personal Protective Equipment for Cryogen Work
Cryogen handling requires specific Personal Protective Equipment (PPE). ES&H Manual Chapter 6550 Appendix T1 Required Personal Protective Equipment for Cryogen Work describes how to determine the appropriate PPE for cryogen work and how to obtain it.
T2 Response to Personal Cryogen Exposure
ES&H Manual Chapter 6550 Appendix T2 Response to Personal Cryogen Exposure describes how to recognize and appropriately respond in the event of personal exposure to cryogens.
T3 Emergency Response to Uncontrolled Cryogen Release
ES&H Manual Chapter 6550 Appendix T3 Emergency Response to Uncontrolled Cryogen Release describes how to recognize an uncontrolled cryogen release and the appropriate response procedure steps to follow.

Supplemental Material:

ES&H Manual Chapter 6150 T2 Moving Gas Cylinders from Storage to Work Areab
Only qualified and authorized Cryogenic Workers are allowed to move cryogenic dewars. provides Jefferson Lab's minimum requirements for performing this operation.
ES&H Manual Chapter 6540 T2 ODH Classifications, Engineering and Administrative Control Practices, Training, and Medical Exclusions
Only trained and authorized individuals are allowed access to buildings using cryogenic piping and equipment. These buildings have posted ODH signs that specify requirements for entry. (See ES&H Manual Chapter 6540 Appendix T2 ODH Classifications, Engineering and Administrative Control Practices, Training, and Medical Exclusions for additional information.)
Cryogenic Labeling
Jefferson Lab requires all cryogens used or stored on site to be labeled. Cryogen workers fill out and affix both the content label and National Fire Protection Association (NFPA) label indicating the hazard characteristics associated with the cryogen. These labels are available from the Industrial Hygiene. The exception would be if this information is included on the manufacturer's label.
Cryogenic Repair
The operation of large cryogenic systems requires certain maintenance and repair to be done in the presence of cryogens. Only trained individuals may perform these operations under the authorization of the Senior Cryogenics Coordinator - Accelerator Operations, or for Experimental Halls.


Management authority may be delegated at the discretion of the responsible manager.

Everyone at Jefferson Lab
  • Observe and follow posted requirements.
Qualified Cryogenic Worker
  • Complete and maintain appropriate training and medical monitoring, including:
    • SAF-103 Oxygen Deficient Hazards
  • Wear appropriate personal protective equipment (PPE).
  • Ensure cryogen containers are properly identified, classified, and labeled.
Supervisors/Subcontracting Officer's Technical Representative (SOTR)/Sponsor
  • Identify and ensure worker's training is adequate and current.
  • Assign only trained and qualified cryogen workers to perform operations with cryogenic risks.
  • Ensure that cryogen containers are properly labeled.
  • Ensure appropriate PPE is available and properly used.
  • Maintain cryogenic hazard labels and postings in areas under your authority. (If necessary contact Industrial Hygiene to re-post a sign.)
Senior Cryogenics Coordinator (SSC) for Accelerator Operations and SSC for End Stations
  • Provide consultative assistance to Cryogenic Workers and supervisors.
Industrial Hygiene
  • Distribute cryogen hazard labels and NFPA hazard diamond stickers as needed.
  • Post cryogenic hazard signs when requested.

Document Control:
    APPROVAL DATE:   01/17/17
    REVIEW DATE:  01/17/22
    Periodic Review - 01/17/17 - No changes per TPOC
    Revision 1.3 - 03/19/15 - Updated TPOC from Dana Arenius to Jonathan Creel.
    Revision 1.2 - 07/08/14 - Deleted 'Hazardous Cryogenic Repair Procedure' from Cryogenic Repair.
    Revision 1.1 - 05/20/14 - Added Required Safety Training Table.
    Revision 1.0 - 01/17/12 - Updated to reflect current laboratory operations.

This document is controlled as an on-line file. It may be printed but the print copy is not a controlled document. It is the user's responsibility to ensure that the document is the same revision as the current on line file. .