The Newcastle Upon Tyne Hospitals NHS Foundation Trust
Safe use and storage of liquid nitrogen and solid carbon dioxide (dry ice)
Guidance and information
Version No
Effective From:
Expiry Date:
Date Ratified:
Ratified By:
1
3.1
1 September 2015
1 September 2018
20 August 2015
Health and Safety Committee
Introduction
All departments that use or store cryogenic gas or solids should carry out a risk
assessment, all staff that use liquid nitrogen / cryogenic gases must receive
appropriate training in its safe handling and use. Cryogenic gases / solids are only to
be used in well-ventilated areas where this is not possible static oxygen depletion
monitors must be present.
2
Scope
This document provides guidelines for the storage and handling of cryogenic gases,
mainly liquid nitrogen and solid carbon dioxide (dry Ice).
3
Aims
The aim of these guidelines is to inform all personnel in the safe handling and
storage of liquid nitrogen and solid carbon dioxide (dry Ice).
4
Duties (Roles & Responsibilities)
4.1
Trust Board
The Trust Board is ultimately responsible for fulfilling all Health and Safety
duties as an employer, including all statute Health and safety Law
requirements.
4.2
Chief Executive
The Chief Executive has overall responsibility to the Trust board for ensuring
that appropriate and effective health and Safety management systems are in
place.
4.3
Executive Director
The Chief Executive delegates responsibility for Health and Safety to the
Director of Quality and Effectiveness. The Director of Quality and
Effectiveness deals with matters of health and safety in close association with
Executive Directors, clinical directors, senior managers and the Health and
Safety Lead.
Page 1 of 8
4.4
Directorate Managers and Directorate Directors
Directorate Directorates are responsible for ensuring that day-to day activities
of the directorate/department are conducted in a safe and suitable manner
and this policy is effectively and correctly employed within their own
Directorate.
4.5
Heads of Department
Managers should establish local procedural guidelines specific to their own
departments. Managers should ensure that COSHH and risk assessments
are in place.
4.6
All Staff
All employees are expected to take reasonable care to ensure the safety of
themselves, their colleagues, patients and members of the public. Staff are
responsible for complying with all COSHH/Risk assessments and policies.
All personnel involved in the filling, handling, use or transportation of liquid
nitrogen dewars shall:
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5
Be aware of, and trained in, the hazards of liquid nitrogen
Wear appropriate hand, eye, feet and body protection when
handling full or empty dewars
Not fill, use or transport any dewar with a damaged neck, wall
trunnion support, base support or wheels
Ensure that dewars are correctly and clearly labelled for nitrogen
service before filling
Only use dewars which are correctly and clearly labelled
Only transport dewars which are correctly labelled for transport
Be adequately trained in the handling of liquid nitrogen dewars
Know what actions to take in the event of a liquid spillage
Know what actions to take if in incident results in a cold burn or
asphyxia casualty
Definitions
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Dry Ice – Solid Carbon Dioxide
Dewar- A specific cryogenic container
PPE- Personnel Protective Equipment
SOP- Standard Operating Procedure
6
Liquid Nitrogen
6.1
General Information
All departments that use or store any Cryogenic gas or solids should carry out
a risk assessment. All staff that use liquid nitrogen/cryogenic gases must
receive appropriate training in its safe handling and use. Cryogenic
gases/solids are only to be used in well-ventilated areas where this is not
possible static Oxygen depletion monitors must be present.
Page 2 of 8
6.2
Hazards
Hazards of liquid nitrogen include:
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Asphyxiation due to reduced oxygen levels
Localised oxygen enrichment
Cryogenic (cold) burns by contact with liquid nitrogen or associated cold
surfaces.
6.2.1 Asphyxiation: Liquid Nitrogen rapidly vaporises to gas with about 700
times the liquid volume. By displacing air the gas may kill by
asphyxiation. When the oxygen concentration in air is sufficiently low, a
person can become unconscious without any warning symptoms.
6.2.2 Cold Burns: Extremely low temperatures can freeze flesh rapidly.
When spilled on a surface the liquid tends to cover it completely. The
gas issuing from the liquid is also extremely cold. Delicate tissue, such
as eyes, can be damaged by exposure to cold gas alone. Unprotected
body parts contacting objects cooled by liquid nitrogen may stick fast.
This may result in injuries by flesh being torn whilst attempting to
withdraw from the object. Prolonged inhalation of cold vapour or gas
can damage the lungs. Cryogenic liquids and vapour can damage the
eyes.
6.2.3 Use of Lifts: There is a small risk that should a person remain in a
closed lift for a prolonged time any venting gases may reduce the
oxygen levels sufficiently to cause harm. However to eliminate these
risks the following practice should be followed when transporting
dewars.
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6.3
No one should accompany the dewar inside a lift.
One person should send the dewar and another should be
waiting to receive the dewar from the lift.
Use controlled goods lifts whenever possible. Do not use public
use lifts.
Storage
The location for the storage and use of liquid nitrogen must be chosen in the
following order of preference:
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In a ventilated room sealed from other areas of normal occupancy
at, or above, ground level adjacent to an outside wall as far as possible
from normal workstations
at above, ground level, as far as possible from normal workstations
Liquid nitrogen must not be stored or used below ground level or in corridors.
All pipe-work and valves must be labelled or marked for functions. All vessels
and equipment must be commissioned and handed over by a competent
person.
Page 3 of 8
6.3.1 Workplace: All vessels, work equipment, furniture and other items must
be organised in such away as to allow staff, and other users of the
space, adequate means of access and egress.
6.3.2 Storage of Dewars in Rooms: Storing single dewars of up to 25L in
rooms is considered acceptable with adequate ventilation. However
the storage of large numbers of small dewars or dewars over 25 litre
capacity may require additional precautions to be taken. In these
circumstances consideration should be given to: the size of the room;
the storage conditions: ventilation levels: and, the possible use of low
oxygen level alarms. Dewars must not be stored in sealed rooms (e.g.
Walk in refrigerated rooms) because the reduced ventilation may be
inadequate to mitigate against spillage and general evaporation.
6.3.3 Containers: Use only containers designed for low-temperature liquids.
Cryogenic containers (e.g. Dewar flasks) are specifically designed and
made of materials that can withstand the rapid changes and extreme
temperature differences encountered in working with liquid nitrogen.
Even so, these special containers should be filled slowly to minimise
the internal stresses that occur when any material is cooled.


Do not cover or plug the entrance opening of any liquid
nitrogen refrigerator or dewar.
Do not use any stopper or other device that would
interfere with venting gas.
Cryogenic liquid containers are generally designed to operate with little
or no internal pressure inadequate venting can result in excessive gas
pressure which could damage or burst the container. Check the unit
periodically to be sure that the venting is not restricted by accumulated
ice or frost.
6.4
Labelling
Liquid nitrogen dewars shall be clearly and adequately labelled. The Label
includes:
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Basic safety information
Transport labelling information
Gas supplier contacts.
Page 4 of 8
6.5
Maintenance of equipment
All large capacity storage equipment (25 litres or larger) should be subject to
annual maintenance checks. Smaller dewars should be visually inspected.
6.6
Protective Clothing
When using or decanting liquid nitrogen a face visor must be worn.
Always wear appropriate gloves when handling anything that is, or may have
been, in immediate contact with liquid nitrogen. Use tongs to withdraw objects
immersed in the liquid, and handle the object carefully.
Never put hands (even in the best gloves) into liquid nitrogen.
Appropriate gloves are thermal protective gloves which are specifically
designed for cryogenic use, with close fitting ribbed cuffs to prevent liquid
nitrogen from spilling inside the glove. When decanting liquid nitrogen, a
splash resistant apron may be appropriate.
6.7
Transport
Only use closed ‘onion’ dewars and transport dewars when moving liquid
nitrogen. When transporting large quantities of liquid nitrogen / solid carbon
dioxide and when using lifts this task should be undertaken by 2 members of
staff. Keep the unit upright at all times. Tipping the container or laying it on
its side can cause spillage of liquid nitrogen. It may also damage the
container and any materials stored in it. Rough handling can cause serious
damage to dewars. Dropping the container allowing it to fall over on its side,
or subjecting it to sharp impact or severe vibration can result in partial or
complete loss of vacuum. To protect the vacuum insulation system, handle
containers carefully. Do not ‘walk’, roll or drag Dewars across a floor. Large
units are heavy enough to cause personal injury or damage to equipment if
proper lifting and handling techniques are not used. Avoid transport on
vehicles where the load space is not separated from the driver’s
compartment. Ensure vehicle driver is aware of the potential hazards of the
load and knows what to do in the event of an accident or an emergency.
Before transporting product containers, ensure that they are firmly secured.
6.8
Disposal
Never dispose of cryogenic liquids down the drain. Ordinary materials may
not be able to withstand cryogenic temperatures without failure. Laboratory
plumbing is a common example. Allow waste liquid nitrogen to evaporate
naturally in a fume hood or, preferably, pour the liquid slowly on gravel or bare
earth, from which other people are excluded, where it can evaporate without
causing damage. Do not pour the liquid on the pavement.
Page 5 of 8
6.9
First Aid
6.9.1 Skin / Eye Contact
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Immediately flush thoroughly with copious quantities of
tepid water (the water must not be hotter than 44C).
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DO NOT apply any form of direct heat.
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DO NOT rub affected parts either before or after warming.

Move patient to a warm place (22C).
The aim is to slowly raise the temperature of the affected area back to
normal. For minor injuries make the injured person comfortable and
loosen any clothing that may restrict blood circulation. Do not pull
clothes away from burned or frozen area.
Use a sterile burn dressing to protect the injury and to get the patient to
the Hospital casualty department.
DO NOT permit smoking or alcohol consumption or give analgesics
(aspirin, paracetamol etc).
6.9.2 Anoxia: If a person seems to become dizzy or loses consciousness
while working with liquid nitrogen, move to a well ventilated area
immediately. In contained areas self-contained breathing apparatus
should be worn unless atmosphere is proved to be safe.
6.10 Dry Ice: Carbon Dioxide (Solid) CO2
Dry ice is frozen carbon dioxide (CO2). It is denser and colder than traditional
ice. In addition, Dry Ice does not melt-it sublimates. Sublimation is the
process of going directly from a solid to a gas.
6.10.1 Hazard: Contact with product may cause cold burns or frostbite. In high
concentrations sublimed vapour may cause asphyxiation.
6.10.2 General Precautions: All staff who use Dry Ice must receive appropriate
training in its safe handling and use.
6.10.3 Handling and Use Precautions:
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Do not handle Dry Ice with bare hands always wear suitable
insulated gloves.
Use only specified equipment which is suitable for the storage or
transportation of Dry Ice.
6.10.4 First aid Measures
Skin / Eye contact with Dry Ice
Immediately flush eyes thoroughly with water for at least 15 minutes. In
case of cold burns/frost bite, apply a sterile dressing and seek medical
assistance.
Page 6 of 8
6.11 Summary of Recommendations

Carry out a risk-assessment in accordance with the Management of
Health & Safety at work Regulations (8) and, where necessary, the
confined Spaces Regulations (1).

Ensure that all employees are adequately trained in the handling of
dewars and are aware of the hazards of liquid nitrogen and that proper
operating procedures are in place.

Ensure that adequate ventilation is provided in areas dewars are used
or stored.
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Ensure that adequate procedures are in place for the transportation of
dewars within the premises particularly in respect to the use of lifts and
stairs.
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Ensure that manual handling assessments have been carried out on all
activities involving dewars.
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Ensure that labelling meets all regulatory requirements.
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Ensure that dewars are adequately maintained and that they are in
good condition.
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Ensure that adequate emergency procedures are in place in the event
of a liquid spillage.
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Ensure that a sufficient number of personnel are trained in the
treatment of asphyxia and cold burns.
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Carry out actions resulting from risk assessments.
7
Training
Training will be facilitated by the staff Development Department, and be accessible
to all employees.
8
Equality & Diversity
The Trust is committed to ensuring that, as far as is reasonably practicable, the way
we provide services to the public and the way we treat our staff reflects their
individual needs and does not discriminate against individuals or groups on any
grounds.
9
Monitoring Compliance
Standard /
Process / Issue
Compliance of
cryogenic
gases/solids risk
assessments.
10
-
Monitoring and Audit
Method
By
Health and
Health and
Safety
Safety
compliance
Advisors
questionnaire.
Consultation & Review
H&S
Trust Health and Safety Committee
CPG
Page 7 of 8
Committee
Health and
safety
committee
Frequency
Quarterly
11
Implementation (including raising awareness)
To be included under the COSHH assessor programmes
12
References

Health and Safety at Work act 1974
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The Management of Health and Safety at Work Regulations 1992/1999

The Control of Substances Hazardous to Health Regulations 1999

The Personal Protective Equipment at Work Regulations 1992
13
Associated Documentation

Health and Safety Operational Policy
Page 8 of 8
The Newcastle upon Tyne Hospitals NHS Foundation Trust
Equality Analysis Form A
This form must be completed and attached to any procedural document when submitted to the appropriate committee for consideration and approval.
PART 1
1.
Assessment Date:
2.
Name of policy / strategy / service:
Safe use and storage of liquid nitrogen and solid carbon dioxide
3.
Name and designation of Author:
Paul Clancy Health and Safety Advisor
4.
Names & designations of those involved in the impact analysis screening process:
As above
5.
Is this a:
Is this:
Who is affected
7/08/15
Policy
X
New
Employees
Strategy
Service
Revised
X
Service Users
Wider Community
6.
What are the main aims, objectives of the policy, strategy, or service and the intended outcomes? (These can be cut and pasted from your policy)
The aim of these guidelines is to inform all Trust personnel in the safe handling and storage of liquid nitrogen and solid carbon
dioxide.
7.
Does this policy, strategy, or service have any equality implications?
Yes
No
X
If No, state reasons and the information used to make this decision, please refer to paragraph 2.3 of the Equality Analysis
Guidance before providing reasons:
This policy advises on the safe use of COSHH products by Trust staff, and has no equality impact.
8.
Summary of evidence related to protected characteristics
Protected Characteristic
Evidence, i.e. What evidence
do you have that the Trust is
meeting the needs of people
in various protected Groups
Does evidence/engagement highlight areas of
direct or indirect discrimination? If yes describe
steps to be taken to address (by whom,
completion date and review date)
Race / Ethnic origin (including
gypsies and travellers)
Sex (male/ female)
Religion and Belief
Sexual orientation including
lesbian, gay and bisexual people
Age
Disability – learning difficulties,
physical disability, sensory
impairment and mental health.
Consider the needs of carers in this
section
Gender Re-assignment
Marriage and Civil Partnership
Maternity / Pregnancy
n/a
n/a
Does the evidence highlight any areas to
advance opportunities or foster good
relations. If yes what steps will be
taken? (by whom, completion date and
review date)
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
9.
Are there any gaps in the evidence outlined above? If ‘yes’ how will these be rectified?
No
10.
Engagement has taken place with people who have protected characteristics and will continue through the Equality Delivery
System and the Equality Diversity and Human Rights Group. Please note you may require further engagement in respect of any
significant changes to policies, new developments and or changes to service delivery. In such circumstances please contact
the Equality and Diversity Lead or the Involvement and Equalities Officer.
Do you require further engagement?
11.
Yes
No
X
Could the policy, strategy or service have a negative impact on human rights? (E.g. the right to respect for private and family
life, the right to a fair hearing and the right to education?
No
PART 2
Name:
Paul Clancy
Date of completion:
7/08/15
(If any reader of this procedural document identifies a potential discriminatory impact that has not been identified, please refer to the Policy Author identified above,
together with any suggestions for action required to avoid/reduce the impact.)