SUBJECT:
Cryogenic Safety Procedures
SAFETY
PAGE: 1
OF: 9
DEPARTMENT: Scientific Staff
EFFECTIVE: July 2010
APPROVED BY: Safety
REVISED: April 2013
Purpose:
The purpose of this document is to inform individuals on the safe work practices that should be adhered
to when working with or handling cryogenic gases.
Procedure;
Cryogenic materials are extremely cold and call for special handling, tools and personal protection.
Liquified gases will freeze skin on contact, so you should wear nonporous gloves intended for cryogenic
work. Boots/total foot covering and long clothing will prevent accidental contact from spills. Since
cryogenic temperatures can also damage many materials, use only containers and equipment designed to
handle these conditions. Many people work with cryogenics every day, so using the right equipment and
following simple procedures will keep them safe.
Staff and Administrative Responsibility:
It is the responsibility of the Scientist In Charge (or designee) of the apparatus to ensure that the
cryogenic safety hazards are reduced to as low a level as is reasonably achievable. This will include:
(1) A safety analysis and review for all cryogenic areas
(2) Cryogenic safety and operational training for relevant personnel,
(3) Upkeep of appropriate maintenance and inspection schedules and records
(to be performed by the chemical supplier-based on the small quantity that will be on-hand).
It is the responsibility of the Scientist in Charge or designee to maintain the system in the original working
order, i.e. the condition in which the system was approved for use. Alterations to the system which impact
worker safety must be reported to the Physics Plant Manager or the Safety Officer.
*** NEVER WORK ALONE! *****
The ultimate responsibility for safety rests with the worker and is best ensured by thorough education
and awareness
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SUBJECT:
Cryogenic Safety Procedures
SAFETY
DEPARTMENT: Scientific Staff
PAGE: 2
OF: 9
EFFECTIVE: July 2010
APPROVED BY: Safety
REVISED: April 2013
Primary Hazards
Cryogenic materials have temperatures roughly lower than -150C. This will instantly cause frostbite or
burn any exposed skin. Prolonged contact will cause serious, possibly life-threatening injury. Because of
this hazard, avoid any direct contact with cryogenic solids or liquids to your skin or eyes.
Very low temperatures cause normally soft, flexible objects such as hoses, gaskets and seals to become
brittle and crack. Cracked parts may have sharp edges, posing a laceration hazard. Store cryogenic
materials only in containers specifically designed for the purpose. Certain closed-cell plastic foams, such
as styrofoam, can contain liquid nitrogen for short periods of time. Metals will undergo thermal
contraction and possibly crack. They will also become extremely cold to the touch.
The safety hazards associated with the use of cryogenic liquids can be categorized as follows:
A. Cold contact burns
Liquid or low-temperature gas from any of the specified cryogenic substances will produce effects
on the skin similar to a burn.
B. Asphyxiation
Degrees of asphyxia will occur when the oxygen content of the working environment is less than
20.9% by volume. Effects from oxygen deficiency become noticeable at levels below ~18% and
sudden death may occur at ~6% oxygen content by volume. This decrease in oxygen content can
be caused by a failure/leak of the cryogenic vessel or transfer line and subsequent vaporization of
the cryogen.
C. Explosion - Pressure
Heat flux into the cryogen from the environment will vaporize the liquid and potentially cause
pressure buildup in cryogenic containment vessels and transfer lines. Adequate pressure relief
must be provided to all parts of a system to permit this routine outgassing and prevent explosion.
D. Explosion - Chemical
Cryogenic fluids with a boiling point below that of liquid oxygen are able to condense oxygen from
the atmosphere. Repeated replenishment of the system can thereby cause oxygen to accumulate
as an unwanted contaminant. Similar oxygen enrichment may occur where condensed air
accumulates on the exterior of cryogenic piping. Violent reactions, e.g. rapid combustion or
explosion, may occur if the materials which make contact with the oxygen are combustible.
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SUBJECT:
Cryogenic Safety Procedures
SAFETY
PAGE: 3
OF: 9
DEPARTMENT: Scientific Staff
EFFECTIVE: July 2010
APPROVED BY: Safety
REVISED: April 2013
Secondary Hazards
Cryogenic liquids boil at room temperature, giving off gases. These gases will be extremely cold. While the
cooling power of a gas is less than a liquid's, you should still keep it at a safe distance.
Never store cryogenic liquids in a sealed container without pressure relief. As the liquids turn to gas,
pressure will build past the container's bursting point, possibly resulting in an explosion.
First Aid Measures
EYES: Never introduce ointment or oil into the eyes without medical advice! In case of freezing or
cryogenic "burns" caused by rapidly evaporating liquid, DO NOT WASH THE EYES WITH HOT OR EVEN
TEPID WATER! Remove victim from the source of contamination. For contact with small amounts of
liquid, open the eyelids wide to allow the liquid to evaporate. For contact with large amounts, rinse with a
low pressure stream of cool water for 15 minutes. Refer the victim to an ophthalmologist for treatment
and follow up. If the victim cannot tolerate light, protect the eyes with dark glasses. The use of bandages
is not recommended as keeping the eyelids closed or exerting pressure on the eyelid may cause further
damage.
SKIN: For dermal contact or frostbite: Remove contaminated clothing and flush affected areas with
lukewarm water. DO NOT USE HOT WATER. A physician should see the patient promptly if contact with
the product has resulted in blistering of the dermal surface or in deep tissue freezing.
INGESTION: A physician should see the patient promptly if the cryogenic "burn" has resulted in blistering
of the dermal surface or deep tissue freezing.
INHALATION: PROMPT MEDICAL ATTENTION IS MANDATORY IN ALL CASES OF
OVEREXPOSURE. Victims should be assisted to an uncontaminated area and inhale fresh air.
Quick removal from the contaminated area is most important. Unconscious persons should be moved to
an uncontaminated area, and if breathing has stopped, administer artificial resuscitation and
supplemental oxygen.
Seek professional medical attention.
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SUBJECT:
Cryogenic Safety Procedures
SAFETY
DEPARTMENT: Scientific Staff
PAGE: 4
OF: 9
EFFECTIVE: July 2010
APPROVED BY: Safety
REVISED: April 2013
Personal Protective Equipment
Whenever handling or transfer of cryogenic fluids might result in exposure to the cold liquid, boil-off gas,
or surface, protective clothing shall be worn. This will include:
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REMOVAL OF ALL JEWLERY, WATCHES, ETC. FROM HANDS, ARMS AND FINGERS
Face Shield and/or Safety Goggles
Safety Gloves
Long-sleeved shirts, pants and/or Lab Coats
Eye protection is required at all times when working with cryogenic fluids. When pouring a
cryogen, working with a wide mouth dewar or around the exhaust of cold boil-off gas, use of a full
face shield is recommended.
Hand protection is required to guard against the hazard of touching cold surfaces. Loose insulating
gloves can be used.
NEVER WORK ALONE
Use
For general use, dispense cryogenic liquids from the vendor supplied small dewars, into the Styrofoam
container located in the lab hood. After filling the Styrofoam container, specimens will immediately be
dipped into the Styrofoam container and froze using gloves and/or tongs as needed. Frozen biological
specimens, will then be stored in freezer until further use.
Maintenance and Inspection
Cryogenic systems and equipment will be inspected and maintained on a regular basis by the vendor
supplying the fluid.
Training of Cryogenic Personnel
All personnel working with cryogenic fluids must be thoroughly familiar with the hazards involved. They
must also be familiar with all emergency measures that might be required in the event of an accident.
Employees who have not worked with cryogenic fluids and systems must be trained on the job by
experienced employees until thoroughly familiar with safe methods of operation.
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SUBJECT:
Cryogenic Safety Procedures
SAFETY
DEPARTMENT: Scientific Staff
PAGE: 5
OF: 9
EFFECTIVE: July 2010
APPROVED BY: Safety
REVISED: April 2013
The training will address:
 The physical, chemical and physiological hazards associated with cryogenic fluids
 The proper handling procedures for cryogens and cryogenic containers
 Description of the equipment
 Operating procedures
 Maintenance schedule and procedures
 Additionally, each employee will receive training by the responsible scientist on the specific
cryogenic equipment or system he is expected to use.
Handling Emergencies Spills Involving Cryogens
Spill equipment is located at the end of the hall in the Likens Lab and near the Hazardous Waste room.
In the event of a spill or adverse reaction notify Physical Plant Manager, Safety Officer and the Lab
Supervisor immediately that an incident has occurred. Do not attempt to handle a large spill/reaction/fire,
or one in which you are not trained or equipped for. Turn off all ignition sources if this can be done safely;
vacate the area and call for assistance.)
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SUBJECT:
Cryogenic Safety Procedures
SAFETY
PAGE: 6
OF: 9
DEPARTMENT: Scientific Staff
EFFECTIVE: July 2010
APPROVED BY: Safety
REVISED: April 2013
Supervisors: Please return this form to HR within two weeks of the employee’s hire date listed above.
Cryogenics Safety Orientation
Employee Name/Visitor: _______________________________________________
_________________________________
Date of Training: ___________________________________
General CARY IES Safety:
 Review of the MSDS on liquid Nitrogen
 Review of the Cryogenic Safety Procedure
 Responsibility for safety
Primary hazards
Secondary hazards
 First Aid Measures
PPE
Handling Spills and Emergencies
 Emergency Contact Procedure/911 calling procedures
 General Housekeeping
 Safety Resources and Contacts
 1st Aid Equipment Locations
 Reporting Incidents/Injuries
Never work alone
Lab Safety:
 Lab Safety Features
(eyewash, showers and spill control equipment)
Signage for lab door
 Compressed Gases
 Hood Use
 Proper Attire and PPE
 Spill Clean-up Procedures – Incidental Spills ONLY
 Waste Disposal Procedures and Sharps
 Compressed Gas training video (located in Analytical Lab)
 No Eating/Drinking in Labs
 Housekeeping in the Labs
 Fire Evacuation in Labs/No Blocking Exits
 Bloodborne Pathogens
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I acknowledge that I have received training in the topics listed above.
Employee/Visitor’s Signature________________________________________ Date______________
Supervisor/Mentor or Host’s Signature________________________________ Date______________
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SUBJECT:
Cryogenic Safety Procedures
SAFETY
PAGE: 7
DEPARTMENT: Scientific Staff
OF: 9
EFFECTIVE: July 2010
APPROVED BY: Safety
REVISED: April 2013
Warning Sign to be placed on the door when cryogenic material is being used either via transfer from Dewars or tick
freezing process.
LIQUID NITROGEN
IN USE
AUHORIZED PERSONNEL
ONLY
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SUBJECT:
Cryogenic Safety Procedures
SAFETY
DEPARTMENT: Scientific Staff
PAGE: 8
OF: 9
EFFECTIVE: July 2010
APPROVED BY: Safety
02/16/2016
REVISED: April 2013
SUBJECT:
Cryogenic Safety Procedures
SAFETY
PAGE: 9
OF: 9
DEPARTMENT: Scientific Staff
EFFECTIVE: July 2010
APPROVED BY: Safety
REVISED: April 2013
WORKING WITH CRYOGENICS
BASIC SAFETY FACTS
YOU MUST KNOW:
The term cryogenics applies to all temperatures less than -150 C (-238 F). These are compounds that are normally
gases at room temperature, condense to liquids at extremely cold temperatures and the gases can also be
condensed to liquids by exposing them to very high pressures. The extreme temperature of these liquids causes
most solids to become brittle.

Review the Material Safety Data Sheet (MSDS) for liquid nitrogen

Become familiar with emergency procedures

Remove all jewelry from arms and hands prior to beginning any cryogenic work

Never work alone, always make sure that you have another person in the lab at all times

Wear the proper personnel protective equipment (PPE) which includes
o Safety splash goggles
o Face shields
o Long sleeve shirt and pants – NO OPEN TOE SHOES
o Wear cryogenic gloves
o Use ‘tongs’ to handle samples
o Place sign in the lab door indicating ‘Warning Liquid Nitrogen In Use’.

Visually check the Dewar’s for any signs of leakage
PROCEDURE FOR FREEZING:
STEP 1:
1. Place ticks in jars into the card board containers
2. Tie the cardboard containers
3. Go to lab hood and move the exhaust toggle switch to ‘CLOSED –Fumes generated at work surface are
heavier than air’ or sticker that indicates ‘Place exhaust here when freezing with liquid nitrogen’
STEP 2:
1. Place Styrofoam container on stand and place stand under the Dewar’s – put cover back on Styrofoam
container
2. Slowly open up the valve to release the liquid nitrogen in to the Styrofoam container.
3. As liquid is released, slowly increase the flow of liquid nitrogen
4. Visually check the level, use ruler to ensure that you have approximately 3 inches of liquid nitrogen in
Styrofoam container.
5. When the correct level has been reached, turn off the flow of liquid nitrogen
6. Carefully remove the Styrofoam container and relocate to the lab hood
7. Use the tongs to gently place ticks in cardboard containers into the liquid nitrogen
8. Leave in solution for 2 minutes and remove with tongs
9. Immediately take the cardboard container (using the tongs) and place in the negative zero freezers.
10. Repeat steps above.
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