Liquid Nitrogen Safety and Information brought to you by Cryostop
Liquid Nitrogen Safety Standards

1. Safety

1.1. Working With Cryogenic Refrigerants
Liquid Nitrogen is a water-looking liquid (referred to as a "cryogenic refrigerant") that "boils" at a very low temperature, about 320* F. This "boiling" requires lots of heat input, just like the boiling of water. That required heat is drawn from any objects which the liquid refrigerant touches. In simplified terms, the refrigerant boils by sucking the heat out of something. That's why it freezes water at room temperature, and that's why it'll freeze or frostbite your skin quickly.

As Liquid Nitrogen "boils", the vapor produced is nitrogen gas. This gas is a major part of the air we breath. However, if the nitrogen is allowed to concentrate in a non-ventilated work area, and displace (push) the available oxygen away from the work area, asphyxiation (oxygen starvation) of workers can occur. This must and can be easily avoided by following basic safety procedures.

LIQUID NITROGEN REFRIGERANT MUST HANDLED SAFELY AT ALL TIMES.

1.1.1. Personal Protection
For a CRYO-LATOR™ freeze plug operation, personnel are required to wear all conventional safety equipment dictated by our normal standards of industrial work site protection.

In addition, during all phases of the CRYO-LATOR™ freeze plug operation when refrigerant or its vapor is out of its container or dewars, the following additional specific basic safety equipment should be worn/used:

• Safety glasses all personnel inside safety perimeter.
• Face shield all personnel inside safety perimeter.
• Low temp. gloves all personnel touching chilled equipment.
• Oxygen monitor per training standards (minimum one per crew inside the safety perimeter or inside the work site if it is a Confined Space).

1.1.2. Non-Cryostop International Personnel

Frequently, non-Cryostop™ International personnel will need to enter the safety perimeter (defined below) to perform work, etc. The senior Cryostop™ International employee on site shall inform these non-Cryostop™ International personnel of the hazards associated with working around Cryostop ™ and firmly insist that safety protection and precautions as outlined herein be observed by these non-Cryostop™ International personnel. Very importantly, this includes insisting that they are protected with their own oxygen monitors.

1.1.3. Area & Equipment Protection
A Safety Perimeter around all of Cryostop™ International's in-use tanks, dewars and equipment shall be set up and "roped off" with yellow and black safety tape whenever liquid nitrogen is present on the work site outside of its tanks or dewars, ie., during the Cryostop™ freeze plug operation and until all chambers, hoses and piping are boiled free of liquid nitrogen.

This Safety Perimeter shall be set up on a radius of at least 2 times the elevation of the Cryostop™ chambers above the lowest unprotected floor/deck level beneath them, or 20 feet, whichever is greater, and an equal Perimeter around all operating dewars, tanks, hoses and piping.

While the Cryostop™ freeze plug operation is under way, no persons shall be allowed inside this Safety Perimeter without the proper protective clothing, equipment, & monitors, as outlined herein; nor, shall any person be allowed inside this Safety Perimeter that has not been instructed of the hazards inside the Perimeter as outlined in "Working With Cryogenic Refrigerants" under the "Safety" section herein.

Electrical and rotating equipment within this safety perimeter shall be disconnected or stopped or protected by the customer in such a way that an accidental direct hit by a liquid nitrogen stream will not damage the equipment, cause an electrical short incident, or be splashed outside the safety perimeter. The minimum protection acceptable to Cryostop™ International is draped and taped 6-mil polyethylene sheeting.

Any finished (ie., painted or coated) or plastic surfaces inside the safety perimeter, which the customer does not want destroyed in the event of an accidental direct hit by a liquid nitrogen stream, shall be suitably protected by the customer.

1.1.4. Ventilation
Excellent ventilation is critical to safe work around liquid nitrogen and its vapor.
Specific Cryostop™ International rules about ventilation are detailed below.

Control Measures

Respiratory Protection: SCBA for confined space or where ventilation cannot maintain greater than 19.5% oxygen level.
Ventilation: excellent natural or forced air mandatory. It may be necessary to both exhaust nitrogen gas away from work area and move fresh (fully oxygenated) air into work area.

Gloves: liquid-proof/insulated Eye Protection: splash goggles and face shied
Other Protection: full body cover as specified in Cryostop™ International procedures
Work/Hygienic Practices: N/A

1.2. About Liquid Nitrogen
Cryostop™ freeze plugging is normally done using liquefied nitrogen as the cooling material to form the plug. The following information is important for Cryostop™ International personnel to have an adequate understanding of this special material.
Below is a typical MSDS sheet on liquid nitrogen.

MATERIAL SAFETY DATA SHEET

SECTION 1. PRODUCT IDENTIFICATION

SECTION 2. COMPOSITION/INFORMATION ON INGREDIENTS
Nitrogen is sold as pure product > 99%.
CAS NUMBER: 7727-37-9
EXPOSURE LIMITS:
OSHA: Not established ACGIH: Simple asphyxiant

SECTION 3. HAZARD IDENTIFICATION
EMERGENCY OVERVIEW

Liquid nitrogen is a colorless, odorless, extremely cold liquid and gas under pressure. It can cause rapid suffocation when concentrations are sufficient to reduce oxygen levels below 19.5%. Self Contained Breathing Apparatus (SCBA) may be required. Contact with liquid or cold vapors can cause severe frostbite. Cold vapors in the air will appear as a white fog due to condensation of moisture. While this may indicate the presence of the gas it should not be used to determine its concentration in the atmosphere. Oxygen concentrations must be monitored in the release area. All cryogenic liquids produce large volumes of gas when they vaporize. One volume of liquid nitrogen will expand to produce 696.5 equivalent volumes of gas.

EMERGENCY TELEPHONE NUMBERS:
800-523-9374 Continental U.S., Canada and Puerto Rico
610-481-7711 other locations

POTENTIAL HEALTH EFFECTS INFORMATION:
INHALATION: Simple asphyxiant.
EYE CONTACT: Tissue freezing and severe cryogenic burns if contacted into eyes.
SKIN CONTACT: Tissue freezing and severe cryogenic burn of skin.
CHRONIC EFFECTS: None established.
EXPOSURE INFORMATION:
ROUTE OF ENTRY: Inhalation
TARGET ORGANS: None
EFFECT: Asphyxiation (suffocation)

SYMPTOMS:
Exposure to an oxygen deficient atmosphere (<19.5%) may cause dizziness, drowsiness, nausea, vomiting, excess salivation, diminished mental alertness, loss of consciousness and death. Exposure to atmospheres containing 8-10% or less oxygen will quickly bring about unconsciousness without warning, leaving individuals unable to help or protect themselves. Lack of sufficient oxygen can cause serious injury or death.

Skin contact with liquid nitrogen can cause tissue freezing, resulting in severe burns. The burns are caused by the extremely low temperature of the cryogenic liquid and not the result of chemical action. Skin may appear red with the formation of blisters. In cases that involve prolonged or severe exposure, tissue may freeze and have a waxy or yellow appearance.

MEDICAL CONDITIONS AGGRAVATED BY OVEREXPOSURE: None
CARCINOGENIC POTENTIAL: Nitrogen is not listed by NTP, OSHA or IARC as a carcinogen or suspected carcinogen.

SECTION 4. FIRST AID
INHALATION: Persons suffering from lack of oxygen should be moved to fresh air. If victim is not breathing, administer
artificial respiration. If breathing is difficult, administer oxygen. Obtain prompt medical attention.

SKIN CONTACT: Remove any clothing that may restrict circulation to frozen area. Do not rub frozen parts as tissue damage may result. As soon as practical place the affected area in a warm water bath which has a temperature not to exceed 105°F (40°C). Never use dry heat. Call a physician as soon as possible.
Frozen tissue is painless and appears waxy with a possible yellow color. It will become swollen, painful, and prone to infection when thawed. If the frozen part of the body has been thawed, cover the area with dry sterile dressing with a large bulky protective covering, pending medical care. In case of massive exposure, remove clothing while showering with warm water. Call a physician.

EYE CONTACT: For exposure to liquid, immediately warm frostbite area with warm water (not to exceed 105°F).

SECTION 5. FIRE AND EXPLOSION
FLASH POINT: AUTO IGNITION: FLAMMABLE LIMIT:
Not Applicable Nonflammable Nonflammable
EXTINGUISHING MEDIA: Nitrogen is nonflammable and does not support combustion. Use extinguishing media appropriate for the surrounding fire.
HAZARDOUS COMBUSTION PRODUCTS: None

SPECIAL FIRE FIGHTING INSTRUCTIONS: Nitrogen is a simple asphyxiant. If possible, remove nitrogen containers from fire area or cool with water. Do not direct water spray at the container vent. Self contained breathing apparatus may be required for rescue workers. Evacuate the area.

UNUSUAL FIRE AND EXPLOSION HAZARDS: Liquid nitrogen when spilled will vaporize rapidly forming an oxygen deficient vapor cloud. Evacuate this area. Pressure in a container can build up due to heat and it may rupture if pressure relief devices should fail to function. Contact with cold liquid or gaseous oxygen may cause frostbite. Visibility may be obscured in its vapor cloud.

SECTION 6. ACCIDENTAL RELEASE MEASURES
Evacuate all personnel from affected area. Increase ventilation to release area and monitor oxygen level. Use appropriate protective equipment (SCBA). To increase rate of vaporization spray large amounts of water on to the spill from an upwind position. If leak is from container or it's valve, call the Air Products emergency telephone number. Do NOT spray water directly at leak. If leak is in user’s system close cylinder valve and vent pressure before attempting repairs.

SECTION 7. HANDLING AND STORAGE
STORAGE:
Store and use with adequate ventilation. Do not store in a confined space. Cryogenic containers are equipped with pressure relief devices to control internal pressure. Under normal conditions these containers will periodically vent product. Do not plug, remove, or tamper with pressure relief device.

HANDLING:
Never allow any unprotected part of the body to touch uninsulated pipes or vessels which contain cryogenic fluids. The extremely cold metal will cause the flesh to stick fast and tear when one attempts to withdraw from it.
Use a suitable hand truck for container movement. Containers shall be handled and stored in an upright position. Do not drop, tip, or roll containers on their sides. Do not remove or interchange connections. If user experiences any difficulty operating container valve or with container connections discontinue use and contact supplier. Use the proper connection.

DO NOT USE ADAPTERS.
Use piping and equipment adequately designed to withstand pressures to be encountered. Use a check valve or other protective apparatus in any line or piping from the cylinder to prevent reverse flow. To prevent cryogenic liquids or cold gas from being trapped in piping between valves the piping shall be equipped with pressure relief devices. Only transfer lines designed for cryogenic liquids shall be used. Some metals such as carbon steel may become brittle at low temperatures, will easily fracture and should not be used with cryogenic liquids. It is recommended that all vents be piped to the exterior of the building.

SPECIAL PRECAUTIONS:
Some metals, such as carbon steel, may become brittle and fracture at low temperatures.
For additional information concerning storage and handling refer to Compressed Gas Association pamphlet P-12 Safe Handling of Cryogenic Liquids available from the Compressed Gas Association, Inc., 1725 Jefferson Davis Highway, Arlington, VA 22202-4102 Telephone (703) 412-0900.

SECTION 8. PERSONAL PROTECTION / EXPOSURE CONTROL
ENGINEERING CONTROLS: Natural or mechanical ventilation to prevent oxygen deficient atmospheres under 19.5% oxygen.
RESPIRATORY PROTECTION:
General Use: None required.
Emergency Use: Self contained breathing apparatus (SCBA) or positive pressure airline with mask and escape pack are to be used in oxygen deficient atmosphere. Respirators will not function.
PROTECTIVE GLOVES: Loose fitting thermal insulated or leather gloves.
EYE PROTECTION: Full face shield and safety glasses are recommended.
OTHER PROTECTIVE EQUIPMENT: Safety shoes when handling containers. Long sleeve shirts and trousers without cuffs.

SECTION 9. PHYSICAL AND CHEMICAL PROPERTIES
APPEARANCE: Colorless, cryogenic liquid
ODOR: Odorless
MOLECULAR WEIGHT: 28.01
BOILING POINT (1 atm): -320.4 ° F (-195.8 ° C)
SPECIFIC GRAVITY (Air = 1): 0.967
FREEZING POINT/MELTING POINT: -345.8 ° F (-209.9 ° C)
VAPOR PRESSURE (AT 20 ° C): Not applicable
GAS DENSITY (At 70 ° F (21.1 ° C) and 1 Atm): 0.072 lb/ft3 (1.153 kg/m3)
SOLUBILITY IN WATER (Vol/Vol at 32 ° F (0 ° C)): 0.023
EXPANSION RATIO: (For liquid to gas) at 70 ° F (21.1 ° C): 1 to 696.5

SECTION 10. REACTIVITY / STABILITY
CHEMICAL STABILITY: Stable
CONDITIONS TO AVOID: None
INCOMPATIBILITY: None
HAZARDOUS DECOMPOSITION PRODUCTS: None
HAZARDOUS POLYMERIZATION: Will not occur.

SECTION 11. TOXICOLOGICAL INFORMATION
Nitrogen is a simple asphyxiant.

SECTION 12. ECOLOGICAL INFORMATION
The atmosphere contains approximately 78% nitrogen. No adverse ecological effects are expected. Nitrogen does not contain any Class I or Class II ozone depleting chemicals. Nitrogen is not listed as a marine pollutant by DOT 49 CFR.

SECTION 13. DISPOSAL
UNUSED PRODUCT/EMPTY CONTAINER: Return container and unused product to supplier. Do not attempt to dispose of unused product.
DISPOSAL: For emergency disposal, discharge slowly to the atmosphere in a well ventilated area or outdoors.

SECTION 14. TRANSPORTATION
DOT HAZARD CLASS: 2.2
DOT SHIPPING LABEL: Nonflammable Gas
DOT SHIPPING NAME: Nitrogen, Refrigerated Liquid
IDENTIFICATION NUMBER: UN1977
REPORTABLE QUANTITY (RQ): None
SPECIAL SHIPPING INFORMATION: Containers should be transported in a secure upright position in a well ventilated truck. Never transport in passenger compartment of a vehicle.

SECTION 15. REGULATORY INFORMATION
U.S. FEDERAL REGULATIONS:

CERCLA: Comprehensive Environmental Response, Compensation, and Liability Act of 1980 requires notification to the National Response Center of a release of quantities of hazardous substances equal to or greater than the reportable quantities (RQ) in 40 CFR 302.4.
CERCLA REPORTABLE QUANTITY: None
SARA TITLE III: SUPERFUND AMENDMENT AND REAUTHORIZATION ACT OF 1986

SECTION 302: Requires emergency planning based on threshold planning quantities (TPQ) and release reporting based on reportable quantities (RQ) of EPA’s extremely hazardous substances (40 CFR 355).
Nitrogen is not listed as an Extremely Hazardous Substance.

SECTIONS 311/312: Require submission of material safety data sheets (MSDSs) and chemical inventory reporting with identification of EPA defined hazard classes. The hazard classes for this product are:
IMMEDIATE HEALTH: Yes PRESSURE: Yes
DELAYED HEALTH: No REACTIVITY: No
FIRE: No

SECTION 313: Requires submission of annual reports of release of toxic chemicals that appear in 40 CFR 372. This information should be included in all MSDSs that are copied and distributed for this material.
Nitrogen is not listed as a toxic chemical.

TOXIC SUBSTANCE CONTROL ACT (TSCA): Nitrogen is listed on the TSCA inventory.
Environmental Protection Agency (EPA)

40 CFR Part 68: Risk Management for Chemical Accident Release Prevention.
Nitrogen is not listed as a regulated substance.
OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION (OSHA)

29 CFR 1910.119: Process Safety Management of Highly Hazardous Chemicals. Requires facilities to develop a process safety management program based on Threshold Quantities (TQ) of highly hazardous chemicals.
Nitrogen is not listed as a Highly Hazardous Chemical.

SECTION 16. SUPPLEMENTAL INFORMATION
NFPA RATINGS: HMIS RATINGS:
HEALTH: 3 HEALTH: 3
FLAMMABILITY: 0 FLAMMABILITY: 0
REACTIVITY: 0 REACTIVITY: 0
SPECIAL: SA*
*Compressed Gas Association recommendation to designate simple asphyxiant.

** Documents with effective dates of July 1995 and July 1998 are identical in content and either may be used.