LIQUID NITROGEN

To extend surgical margin of excision in cancer operations (Dwyer et al, 1990)
To treat disseminated superficial actinic porokeratosis, elastosis perforans serpiginosa, acne vulgaris cysts, and verrucae (Rosenblum, 1983; Yaffe et al, 1986; Sawyer & Picou, 1989; JEF Reynolds , 1990)

To relieve pain in trigeminal neuralgia (Nally & Zakrzewska, 1984)
Used in medicine and biology for quick freezing of tissues and microorganisms (Clayton & Clayton, 1994)
Used to euthanize dogs, rabbits, and mink (Booth & McDonald, 1982)
Widely used for chilling metals to alter their physical characteristics (Clayton & Clayton, 1994)
Component of fertilizers (ILO, 1983)
Used as carrier gas in gas chromatography (HSDB , 1998)

FORMS

Nitrogen is a colorless, odorless, tasteless gas stored under compression in metal containers. Nitrogen exists in a liquid phase between minus 209.86 degrees Celsius (melting point) and minus 195 degrees Celsius (boiling point) (Rockswold & Buran, 1982).

-CLINICAL EFFECTS

GENERAL CLINICAL EFFECTS

USES: Nitrogen is a basic element that exists in a liquid phase between minus 209.86 degrees C (melting point) and minus 195 degrees C (boiling point). Liquid nitrogen has many uses, including cryosurgery, pain relief for patients with trigeminal neuralgia, quick freezing of tissues and microorganisms, animal euthanasia, chilling metals to alter their characteristics, a component in fertilizers, and as a carrier gas for gas chromatography.

TOXICOLOGY: When used in cryosurgery, liquid nitrogen causes microvascular failure with minimal inflammatory response amidst liquefaction necrosis and progressive fibrosis. Topical damage can occur from the extreme cold of liquid nitrogen, while inhalational toxicity can occur from its freezing effects as well as the displacement of oxygen. Another potential method of toxicity is the development of a venous gas embolism when used in surgery.

EPIDEMIOLOGY: Liquid nitrogen is commonly used for many different industrial and laboratory purposes. Severe toxicity and death secondary to exposure is extremely rare but has been reported.

WITH POISONING/EXPOSURE

Inhalation of liquid nitrogen gas may injure the pharynx. It may also displace oxygen from air and cause asphyxia with associated central nervous system (CNS) injury with prolonged exposure. Topical application can result in a variety of dermal injuries (eg, hyperemia, erythema, bullae, edema, burns, and necrosis), neuropathies, and gas embolism. Syncope and cardiac arrest have also been described. Ingestion of liquid nitrogen can injure the oropharynx, esophagus, and gastric mucosa. Perforation may occur in extremely severe cases.

POTENTIAL HEALTH HAZARDS - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 121 (ERG, 2004)

Vapors may cause dizziness or asphyxiation without warning.
Vapors from liquefied gas are initially heavier than air and spread along ground.

POTENTIAL HEALTH HAZARDS - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 120 (ERG, 2004)

Vapors may cause dizziness or asphyxiation without warning.
Vapors from liquefied gas are initially heavier than air and spread along ground.
Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.

ACUTE CLINICAL EFFECTS

SUMMARY

TOXICOLOGY: When used in cryosurgery, liquid nitrogen causes microvascular failure with minimal inflammatory response amidst liquefaction necrosis and progressive fibrosis. Topical damage can occur from the extreme cold of liquid nitrogen, while inhalational toxicity can occur from its freezing effects as well as the displacement of oxygen. Another potential method of toxicity is the development of a venous gas embolism when used in surgery.
EPIDEMIOLOGY: Liquid nitrogen is commonly used for many different industrial and laboratory purposes. Severe toxicity and death secondary to exposure is extremely rare but has been reported.
TOXICITY: Inhalation of liquid nitrogen gas may injure the pharynx. It may also displace oxygen from air and cause asphyxia with associated central nervous system (CNS) injury with prolonged exposure. Topical application can result in a variety of dermal injuries (eg, hyperemia, erythema, bullae, edema, burns, and necrosis), neuropathies, and gas embolism. Syncope and cardiac arrest have also been described. Ingestion of liquid nitrogen can injure the oropharynx, esophagus, and gastric mucosa. Perforation may occur in extremely severe cases.

Most toxicology references discuss the hazards of excessive nitrogen as a simple asphyxiant. It is capable of displacing oxygen from the breathing atmosphere to less than the concentration essential for maintaining life (Clayton & Clayton, 1994). In ambient environments, the acute toxicity of nitrogen is due to oxygen deprivation (Hunter, 1985; Tabata et al, 1995).

Signs and symptoms of anoxia include decreased visual acuity, night vision, and visual fields, increases in respiratory rate and pulse, decreased performance and alertness, air hunger, fatigue, dizziness, headache, belligerence, euphoria, numbness and tingling in the extremities, sleepiness, mental confusion, hyperventilation, poor judgement, loss of memory, cyanosis, unconsciousness, and death.

Nitrogen has a toxicity of its own at hyperbaric pressures, as documented in divers. At a depth of about 100 feet (30 meters), nitrogen narcosis can occur with rapid onset. This narcosis, ("rapture of the deep"), seriously affects judgement and orientation (Clayton & Clayton, 1994). Under increased pressure, sufficient nitrogen dissolves in the fat-containing brain cells to produce reversible neurological symptoms (Clayton & Clayton, 1994).

Another problem arises with the release of nitrogen from solution in the blood in decompression sickness (caisson disease or bends); this is attributed to the formation of bubbles of gas, mainly nitrogen, in the tissues and blood vessels of persons who have been released too quickly from hyperbaric environments (Sax, 1984; (Clayton & Clayton, 1982). Such hyperbaric studies are not further discussed in this review.

CRYOGENIC EFFECTS: Skin contact with even a small amount of liquid nitrogen can cause serious burns (Clayton & Clayton, 1994). Inhalation of liquid nitrogen vapor has resulted in burns of the lips and oropharynx with signs and symptoms of acute upper airway distress requiring emergency airway management. Large mucosal ulcers developed in the posterior hypopharynx and hard palate, but there were no permanent effects reported in one case (Rockswold & Buran, 1982).

Escaping compressed nitrogen gas may cause FROSTBITE INJURY.

CHRONIC CLINICAL EFFECTS

Of 67 nitrogen plant workers examined, a deficiency of cellular immunity was shown in 14; this value is somewhat higher than that seen in the general population (Ljaljevic, 1977). The occupational exposures in this study were more complex than exposure to nitrogen alone. None of these workers had allergies (Ljaljevic, 1977b).

-FIRST AID

FIRST AID AND PREHOSPITAL TREATMENT

DERMAL EXPOSURE

Liquid nitrogen will rapidly evaporate at room temperature. Washing the skin may not be beneficial.
PREHOSPITAL

Rewarming of a localized area should only be considered if the risk of refreezing is unlikely. Avoid rubbing the frozen area which may cause further damage to the area (Grieve et al, 2011; Hallam et al, 2010).

REWARMING

Do not institute rewarming unless complete rewarming can be assured; refreezing thawed tissue increases tissue damage. Place affected area in a water bath with a temperature of 40 to 42 degrees Celsius for 15 to 30 minutes until thawing is complete. The bath should be large enough to permit complete immersion of the injured part, avoiding contact with the sides of the bath. A whirlpool bath would be ideal. Some authors suggest a mild antibacterial (ie, chlorhexidine, hexachlorophene or povidone-iodine) be added to the bath water. Tissues should be thoroughly rewarmed and pliable; the skin will appear a red-purple color (Grieve et al, 2011; Hallam et al, 2010; Murphy et al, 2000).
Correct systemic hypothermia which can cause cold diuresis due to suppression of antidiuretic hormone; consider IV fluids (Grieve et al, 2011).
Rewarming may be associated with increasing acute pain, requiring narcotic analgesics.
For severe frostbite, clinical trials have shown that pentoxifylline, a phosphodiesterase inhibitor, can enhance tissue viability by increasing blood flow and reducing platelet activity (Hallam et al, 2010).

WOUND CARE

Digits should be separated by sterile absorbent cotton; no constrictive dressings should be used. Protective dressings should be changed twice per day.
Perform twice daily hydrotherapy for 30 to 45 minutes in warm water at 40 degrees Celsius. This helps debride devitalized tissue and maintain range of motion. Keep the area warm and dry between treatments (Hallam et al, 2010; Murphy et al, 2000).
The injured extremities should be elevated and should not be allowed to bear weight.
In patients at risk for infection of necrotic tissue, prophylactic antibiotics and tetanus toxoid have been recommended by some authors (Hallam et al, 2010; Murphy et al, 2000).
Non-tense clear blisters should be left intact due to the risk of infection; tense or hemorrhagic blisters may be carefully aspirated in a setting where aseptic technique is provided (Hallam et al, 2010).
Further surgical debridement should be delayed until mummification demarcation has occurred (60 to 90 days). Spontaneous amputation may occur.
Analgesics may be required during the rewarming phase; however, patients with severe pain should be evaluated for vasospasm.
IMAGING: Arteriography and noninvasive vascular techniques (e.g., plain radiography, laser Doppler studies, digital plethysmography, infrared thermography, isotope scanning), have been useful in evaluating the extent of vasospasm after thawing and assessing whether debridement is needed (Hallam et al, 2010). In cases of severe frostbite, Technetium 99 (triple phase scanning) and MRI angiography have been shown to be the most useful to assess injury and determine the extent or need for surgical debridement (Hallam et al, 2010).
TOPICAL THERAPY: Topical aloe vera may decrease tissue destruction and should be applied every 6 hours (Murphy et al, 2000).
IBUPROFEN THERAPY: Ibuprofen, a thromboxane inhibitor, may help limit inflammatory damage and reduce tissue loss (Grieve et al, 2011; Murphy et al, 2000). DOSE: 400 mg orally every 12 hours is recommended (Hallam et al, 2010).
THROMBOLYTIC THERAPY: Thrombolysis (intra-arterial or intravenous thrombolytic agents) may be beneficial in those patients at risk to lose a digit or a limb, if done within the first 24 hours of exposure. The use of tissue plasminogen activator (t-PA) to clear microvascular thromboses can restore arterial blood flow, but should be accompanied by close monitoring including angiography or technetium scanning to evaluate the injury and to evaluate the effects of t-PA administration. Potential risk of the procedure includes significant tissue edema that can lead to a rise in interstitial pressures resulting in compartment syndrome (Grieve et al, 2011).
CONTROVERSIAL: Adjunct pharmacological agents (ie, heparin, vasodilators, prostacyclins, prostaglandin synthetase inhibitors, dextran) are controversial and not routinely recommended. The role of hyperbaric oxygen therapy, sympathectomy remains unclear (Grieve et al, 2011).
CHRONIC PAIN: Vasomotor dysfunction can produce chronic pain. Amitriptyline has been used in some patients; some patients may need a referral for pain management. Inability to tolerate the cold (in the affected area) has been observed following a single episode of frostbite (Hallam et al, 2010).
MORBIDITIES: Frostbite can produce localized osteoporosis and possible bone loss following a severe case. These events may take a year or more to develop. Children may be at greater risk to develop more severe events (ie, early arthritis) (Hallam et al, 2010).

ORAL EXPOSURE

There is no indication for the use of prehospital activated charcoal.

EYE EXPOSURE

There is no evidence for prehospital decontamination for eye exposures. Patients with eye exposures who are symptomatic should undergo ophthalmologic evaluation for treatment.

INHALATIONAL EXPOSURE

Severe mucosal injury to the hypopharynx may occur. If inhalation of liquid nitrogen gas has occurred, administer 100% humidified oxygen with assisted ventilation as required.

-MEDICAL TREATMENT

LIFE SUPPORT

Support respiratory and cardiovascular function.

SUMMARY

FIRST AID - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 121 (ERG, 2004)

Move victim to fresh air.
Call 911 or emergency medical service.
Give artificial respiration if victim is not breathing.
Administer oxygen if breathing is difficult.
Keep victim warm and quiet.
Ensure that medical personnel are aware of the material(s) involved and take precautions to protect themselves.

FIRST AID - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 120 (ERG, 2004)

Move victim to fresh air.
Call 911 or emergency medical service.
Give artificial respiration if victim is not breathing.
Administer oxygen if breathing is difficult.
Clothing frozen to the skin should be thawed before being removed.
In case of contact with liquefied gas, thaw frosted parts with lukewarm water.
Keep victim warm and quiet.
Ensure that medical personnel are aware of the material(s) involved and take precautions to protect themselves.

FIRST AID

DERMAL EXPOSURE

Liquid nitrogen will rapidly evaporate at room temperatures. Washing the skin may not be beneficial.
PREHOSPITAL

Rewarming of a localized area should only be considered if the risk of refreezing is unlikely. Avoid rubbing the frozen area which may cause further damage to the area (Grieve et al, 2011; Hallam et al, 2010).

REWARMING

Do not institute rewarming unless complete rewarming can be assured; refreezing thawed tissue increases tissue damage. Place affected area in a water bath with a temperature of 40 to 42 degrees Celsius for 15 to 30 minutes until thawing is complete. The bath should be large enough to permit complete immersion of the injured part, avoiding contact with the sides of the bath. A whirlpool bath would be ideal. Some authors suggest a mild antibacterial (ie, chlorhexidine, hexachlorophene or povidone-iodine) be added to the bath water. Tissues should be thoroughly rewarmed and pliable; the skin will appear a red-purple color (Grieve et al, 2011; Hallam et al, 2010; Murphy et al, 2000).
Correct systemic hypothermia which can cause cold diuresis due to suppression of antidiuretic hormone; consider IV fluids (Grieve et al, 2011).
Rewarming may be associated with increasing acute pain, requiring narcotic analgesics.
For severe frostbite, clinical trials have shown that pentoxifylline, a phosphodiesterase inhibitor, can enhance tissue viability by increasing blood flow and reducing platelet activity (Hallam et al, 2010).

WOUND CARE

Digits should be separated by sterile absorbent cotton; no constrictive dressings should be used. Protective dressings should be changed twice per day.
Perform twice daily hydrotherapy for 30 to 45 minutes in warm water at 40 degrees Celsius. This helps debride devitalized tissue and maintain range of motion. Keep the area warm and dry between treatments (Hallam et al, 2010; Murphy et al, 2000).
The injured extremities should be elevated and should not be allowed to bear weight.
In patients at risk for infection of necrotic tissue, prophylactic antibiotics and tetanus toxoid have been recommended by some authors (Hallam et al, 2010; Murphy et al, 2000).
Non-tense clear blisters should be left intact due to the risk of infection; tense or hemorrhagic blisters may be carefully aspirated in a setting where aseptic technique is provided (Hallam et al, 2010).
Further surgical debridement should be delayed until mummification demarcation has occurred (60 to 90 days). Spontaneous amputation may occur.
Analgesics may be required during the rewarming phase; however, patients with severe pain should be evaluated for vasospasm.
IMAGING: Arteriography and noninvasive vascular techniques (e.g., plain radiography, laser Doppler studies, digital plethysmography, infrared thermography, isotope scanning), have been useful in evaluating the extent of vasospasm after thawing and assessing whether debridement is needed (Hallam et al, 2010). In cases of severe frostbite, Technetium 99 (triple phase scanning) and MRI angiography have been shown to be the most useful to assess injury and determine the extent or need for surgical debridement (Hallam et al, 2010).
TOPICAL THERAPY: Topical aloe vera may decrease tissue destruction and should be applied every 6 hours (Murphy et al, 2000).
IBUPROFEN THERAPY: Ibuprofen, a thromboxane inhibitor, may help limit inflammatory damage and reduce tissue loss (Grieve et al, 2011; Murphy et al, 2000). DOSE: 400 mg orally every 12 hours is recommended (Hallam et al, 2010).
THROMBOLYTIC THERAPY: Thrombolysis (intra-arterial or intravenous thrombolytic agents) may be beneficial in those patients at risk to lose a digit or a limb, if done within the first 24 hours of exposure. The use of tissue plasminogen activator (t-PA) to clear microvascular thromboses can restore arterial blood flow, but should be accompanied by close monitoring including angiography or technetium scanning to evaluate the injury and to evaluate the effects of t-PA administration. Potential risk of the procedure includes significant tissue edema that can lead to a rise in interstitial pressures resulting in compartment syndrome (Grieve et al, 2011).
CONTROVERSIAL: Adjunct pharmacological agents (ie, heparin, vasodilators, prostacyclins, prostaglandin synthetase inhibitors, dextran) are controversial and not routinely recommended. The role of hyperbaric oxygen therapy, sympathectomy remains unclear (Grieve et al, 2011).
CHRONIC PAIN: Vasomotor dysfunction can produce chronic pain. Amitriptyline has been used in some patients; some patients may need a referral for pain management. Inability to tolerate the cold (in the affected area) has been observed following a single episode of frostbite (Hallam et al, 2010).
MORBIDITIES: Frostbite can produce localized osteoporosis and possible bone loss following a severe case. These events may take a year or more to develop. Children may be at greater risk to develop more severe events (ie, early arthritis) (Hallam et al, 2010).

ORAL EXPOSURE

There is no indication for the use of prehospital activated charcoal.

EYE EXPOSURE

There is no evidence for prehospital decontamination for eye exposures. Patients with eye exposures who are symptomatic should undergo ophthalmologic evaluation for treatment.

INHALATIONAL EXPOSURE

Severe mucosal injury to the hypopharynx may occur. If inhalation of liquid nitrogen gas has occurred, administer 100% humidified oxygen with assisted ventilation as required.

-RANGE OF TOXICITY

MINIMUM LETHAL EXPOSURE

Asphyxia leading to death may occur when the oxygen concentration in the air is reduced to 6% or less (Kizer, 1984).

MAXIMUM TOLERATED EXPOSURE

Signs of asphyxia may evident when the liquid nitrogen gas displaces oxygen in the air such that the oxygen concentration is 15% or less (Kizer, 1984; Sax & Lewis, 1996).

Carcinogenicity Ratings for CAS7727-37-9 :

ACGIH (American Conference of Governmental Industrial Hygienists, 2010): Not Listed ; Listed as: Nitrogen
EPA (U.S. Environmental Protection Agency, 2011): Not Listed
IARC (International Agency for Research on Cancer (IARC), 2016; International Agency for Research on Cancer, 2015; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2010; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2010a; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2008; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2007; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2006; IARC, 2004): Not Listed
NIOSH (National Institute for Occupational Safety and Health, 2007): Not Listed
MAK (DFG, 2002): Not Listed
NTP (U.S. Department of Health and Human Services, Public Health Service, National Toxicology Project ): Not Listed

TOXICITY AND RISK ASSESSMENT VALUES

EPA IRIS

EPA Risk Assessment Values for CAS7727-37-9 (U.S. Environmental Protection Agency, 2011):

Not Listed

-STANDARDS AND LABELS

WORKPLACE STANDARDS

ACGIH TLV Values for CAS7727-37-9 (American Conference of Governmental Industrial Hygienists, 2010):

Editor's Note: The listed values are recommendations or guidelines developed by ACGIH(R) to assist in the control of health hazards. They should only be used, interpreted and applied by individuals trained in industrial hygiene. Before applying these values, it is imperative to read the introduction to each section in the current TLVs(R) and BEI(R) Book and become familiar with the constraints and limitations to their use. Always consult the Documentation of the TLVs(R) and BEIs(R) before applying these recommendations and guidelines.

Adopted Value

Nitrogen

TLV:

TLV-TWA:
TLV-STEL:
TLV-Ceiling:

Notations and Endnotes:

Carcinogenicity Category: Not Listed
Codes: D
Definitions:

D: Simple asphyxiant; see discussion covering Minimal Oxygen Content found in the "Definitions and Notations" section following the NIC tables (in TLV booklet).

TLV Basis - Critical Effect(s): Asphyxia
Molecular Weight: 14.01

For gases and vapors, to convert the TLV from ppm to mg/m(3):

[(TLV in ppm)(gram molecular weight of substance)]/24.45

For gases and vapors, to convert the TLV from mg/m(3) to ppm:

[(TLV in mg/m(3))(24.45)]/gram molecular weight of substance

AIHA WEEL Values for CAS7727-37-9 (AIHA, 2006):

Not Listed

NIOSH REL and IDLH Values for CAS7727-37-9 (National Institute for Occupational Safety and Health, 2007):

Not Listed

OSHA PEL Values for CAS7727-37-9 (U.S. Occupational Safety, and Health Administration (OSHA), 2010):

Not Listed

OSHA List of Highly Hazardous Chemicals, Toxics, and Reactives for CAS7727-37-9 (U.S. Occupational Safety and Health Administration, 2010):

Not Listed

ENVIRONMENTAL STANDARDS

EPA CERCLA, Hazardous Substances and Reportable Quantities for CAS7727-37-9 (U.S. Environmental Protection Agency, 2010):

Not Listed

EPA CERCLA, Hazardous Substances and Reportable Quantities, Radionuclides for CAS7727-37-9 (U.S. Environmental Protection Agency, 2010):

Not Listed

EPA RCRA Hazardous Waste Number for CAS7727-37-9 (U.S. Environmental Protection Agency, 2010b):

Not Listed
Editor's Note: The D, F, and K series waste numbers and Appendix VIII to Part 261 -- Hazardous Constituents were not included. Please refer to 40 CFR Part 261.

EPA SARA Title III, Extremely Hazardous Substance List for CAS7727-37-9 (U.S. Environmental Protection Agency, 2010):

Not Listed

EPA SARA Title III, Community Right-to-Know for CAS7727-37-9 (40 CFR 372.65, 2006; 40 CFR 372.28, 2006):

Not Listed

DOT List of Marine Pollutants for CAS7727-37-9 (49 CFR 172.101 - App. B, 2005):

Not Listed

EPA TSCA Inventory for CAS7727-37-9 (EPA, 2005):

Not Listed

SHIPPING REGULATIONS

SURFACE

DOT -- Table of Hazardous Materials and Special Provisions for UN/NA Number 1066 (49 CFR 172.101, 2005):

Hazardous materials descriptions and proper shipping name: Nitrogen, compressed

Symbol(s): Not Listed
Hazard class or Division: 2.2

2.2: Non-flammable compressed gas. See 49 CFR section 173.115 for definitions.

Identification Number: UN1066
Packing Group: Not Listed
Label(s) required (if not excepted): 2.2

2.2: Non-Flammable Gas.

Special Provisions:

Not Listed

Packaging Authorizations (refer to 49 CFR 173.***):

Exceptions: 306
Non-bulk packaging: 302
Bulk packaging: 314, 315

Quantity Limitations:

Passenger aircraft or railcar: 75 kg
Cargo aircraft only: 150 kg

Vessel Stowage Requirements:

Vessel stowage location: A

A: The material may be stowed "on deck" or "under deck" on a cargo vessel and on a passenger vessel.

Vessel stowage other: Not Listed

DOT -- Table of Hazardous Materials and Special Provisions for UN/NA Number 1977 (49 CFR 172.101, 2005):

Hazardous materials descriptions and proper shipping name: Nitrogen, refrigerated liquid cryogenic liquid

Symbol(s): Not Listed
Hazard class or Division: 2.2

2.2: Non-flammable compressed gas. See 49 CFR section 173.115 for definitions.

Identification Number: UN1977
Packing Group: Not Listed
Label(s) required (if not excepted): 2.2

2.2: Non-Flammable Gas.

Special Provisions: T75, TP5

T75: Applicable refrigerated liquefied gases are authorized to be transported in portable tanks in accordance with the requirements of sxn.178.277 of this subchapter.
TP5: For a portable tank used for the transport of flammable refrigerated liquefied gases or refrigerated liquefied oxygen, the maximum rate at which the portable tank may be filled must not exceed the liquid flow capacity of the primary pressure relief system rated at a pressure not exceeding 120 percent of the portable tank's design pressure. For portable tanks used for the transport of refrigerated liquefied helium and refrigerated liquefied atmospheric gas (except oxygen), the maximum rate at which the tank is filled must not exceed the liquid flow capacity of the pressure relief device rated at 130 percent of the portable tank's design pressure. Except for a portable tank containing refrigerated liquefied helium, a portable tank shall have an outage of at least two percent below the inlet of the pressure relief device or pressure control valve, under conditions of incipient opening, with the portable tank in a level attitude. No outage is required for helium.

Packaging Authorizations (refer to 49 CFR 173.***):

Exceptions: 320
Non-bulk packaging: 316
Bulk packaging: 318

Quantity Limitations:

Passenger aircraft or railcar: 50 kg
Cargo aircraft only: 500 kg

Vessel Stowage Requirements:

Vessel stowage location: D

D: The material must be stowed "on deck only" on a cargo vessel and on a passenger vessel carrying a number of passengers limited to not more than the larger of 25 passengers or one passenger per each 3 m of overall vessel length, but the material is prohibited on passenger vessels in which the limiting number of passengers is exceeded.

Vessel stowage other: Not Listed

ICAO International Shipping Name for UN1066 (ICAO, 2002):

Proper Shipping Name: Nitrogen, compressed
UN Number: 1066

ICAO International Shipping Name for UN1977 (ICAO, 2002):

Proper Shipping Name: Nitrogen, refrigerated liquid
UN Number: 1977

LABELS

NFPA

NFPA Hazard Ratings for CAS7727-37-9 (NFPA, 2002):

Not Listed

-PERSONAL PROTECTION

SUMMARY

RECOMMENDED PROTECTIVE CLOTHING - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 121 (ERG, 2004)

Wear positive pressure self-contained breathing apparatus (SCBA).
Structural firefighters' protective clothing will only provide limited protection.

RECOMMENDED PROTECTIVE CLOTHING - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 120 (ERG, 2004)

Wear positive pressure self-contained breathing apparatus (SCBA).
Structural firefighters' protective clothing will only provide limited protection.
Always wear thermal protective clothing when handling refrigerated/cryogenic liquids or solids.

Avoid breathing the vapors from this material and do not attempt to handle broken or leaking containers without proper protective equipment (AAR, 1987). Do not touch spilled liquid (CHRIS , 1985).

Appropriate chemical protective gloves and goggles should be worn (AAR, 1987).
Special protective clothing designed to prevent liquid nitrogen or its cold vapors from contacting the body should be worn (NFPA, 1986).
Safety glasses or a face shield, insulated gloves, a long-sleeved shirt, and full-length trousers worn with the cuffs outside boots or over high-topped shoes to prevent spilled liquid from pooling in footwear should be worn when handling this material (CHRIS , 1985).

A self-contained breathing apparatus should also be worn if insufficient oxygen may be present (CHRIS , 1985).

RESPIRATORY PROTECTION

Refer to "Recommendations for respirator selection" in the NIOSH Pocket Guide to Chemical Hazards on TOMES Plus(R) for respirator information.

PROTECTIVE CLOTHING

CHEMICAL PROTECTIVE CLOTHING. Search results for CAS 7727-37-9.

Specific recommendations and test data for this chemical were not found in the available manufacturers' product literature. A complete list of consulted manufacturers and references is presented below.

-PHYSICAL HAZARDS

FIRE HAZARD

SUMMARY

Editor's Note: Information from more than one emergency response guide is associated with this material.
POTENTIAL FIRE OR EXPLOSION HAZARDS - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 121 (ERG, 2004)
- Non-flammable gases.
- Containers may explode when heated.
- Ruptured cylinders may rocket.
POTENTIAL FIRE OR EXPLOSION HAZARDS - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 120 (ERG, 2004)
- Non-flammable gases.
- Containers may explode when heated.
- Ruptured cylinders may rocket.
Nitrogen is noncombustible (AAR, 1987; (CHRIS , 1985). A firefighting medium suitable for fires in surrounding combustible materials should be chosen (AAR, 1987).
Containers that are exposed to the heat of a fire should be cooled from the side with flooding amounts of water until well after the fire is extinguished (AAR, 1987; NFPA, 1986).
- Water should be applied from as far away as possible (AAR, 1987).
Containers should be moved from the area of the fire and leaks stopped if this can be done without undue risk (AAR, 1987).
DOT Evaluation (RTECS , 1989)
- DOT-Hazard: Nonflammable Gas
- Label: Nonflammable Gas
NFPA Classification (CHRIS , 1985)
- Health: 3
- Flammability: 0
- Reactivity: 0

FLAMMABILITY CLASSIFICATION

NFPA Flammability Rating for CAS7727-37-9 (NFPA, 2002):

Not Listed

FIRE CONTROL/EXTINGUISHING AGENTS

FIRE PRECAUTIONS - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 121 (ERG, 2004)

Use extinguishing agent suitable for type of surrounding fire.
Move containers from fire area if you can do it without risk.
Damaged cylinders should be handled only by specialists.

FIRE PRECAUTIONS - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 120 (ERG, 2004)

Use extinguishing agent suitable for type of surrounding fire.
Move containers from fire area if you can do it without risk.
Damaged cylinders should be handled only by specialists.

TANK FIRE PRECAUTIONS - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 121 (ERG, 2004)

Fight fire from maximum distance or use unmanned hose holders or monitor nozzles.
Cool containers with flooding quantities of water until well after fire is out.
Do not direct water at source of leak or safety devices; icing may occur.
Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank.
ALWAYS stay away from tanks engulfed in fire.

TANK FIRE PRECAUTIONS - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 120 (ERG, 2004)

Fight fire from maximum distance or use unmanned hose holders or monitor nozzles.
Cool containers with flooding quantities of water until well after fire is out.
Do not direct water at source of leak or safety devices; icing may occur.
Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank.
ALWAYS stay away from tanks engulfed in fire.

NFPA Extinguishing Methods for CAS7727-37-9 (NFPA, 2002):

Not Listed

A firefighting medium suitable for fires in surrounding combustible materials should be chosen as nitrogen is noncombustible (AAR, 1987).

REACTIVITY HAZARD

Liquid nitrogen has potentially hazardous reactions with (NFPA, 1986; Sax & Lewis, 1989):

Lithium
Neodynium
Titanium

Heat from contact with water will rapidly vaporize liquid nitrogen (CHRIS , 1985).

Liquid nitrogen does not react with common materials, but the low temperature can cause rubber and plastics to become brittle (CHRIS , 1985).

EVACUATION PROCEDURES

SUMMARY

Editor's Note: This material is not listed in the Table of Initial Isolation and Protective Action Distances.

LARGE SPILL - PUBLIC SAFETY EVACUATION DISTANCES - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 121 (ERG, 2004)

Consider initial downwind evacuation for at least 100 meters (330 feet).

LARGE SPILL - PUBLIC SAFETY EVACUATION DISTANCES - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 120 (ERG, 2004)

Consider initial downwind evacuation for at least 100 meters (330 feet).

FIRE - PUBLIC SAFETY EVACUATION DISTANCES - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 121 (ERG, 2004)

If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions.

FIRE - PUBLIC SAFETY EVACUATION DISTANCES - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 120 (ERG, 2004)

If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions.

PUBLIC SAFETY MEASURES - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 121 (ERG, 2004)

CALL Emergency Response Telephone Number on Shipping Paper first. If Shipping Paper not available or no answer, refer to appropriate telephone number:

MEXICO:

SETIQ:

01-800-00-214-00 in the Mexican Republic;
For calls originating in Mexico City and the Metropolitan Area: 5559-1588;
For calls originating elsewhere, call: 011-52-555-559-1588.

CENACOM:

01-800-00-413-00 in the Mexican Republic;
For calls originating in Mexico City and the Metropolitan Area: 5550-1496, 5550-1552, 5550-1485, or 5550-4885;
For calls originating elsewhere, call: 011-52-555-550-1496, or 011-52-555-550-1552; 011-52-555-550-1485, or 011-52-555-550-4885.

ARGENTINA:

CIQUIME:

0-800-222-2933 in the Republic of Argentina;
For calls originating elsewhere, call: +54-11-4613-1100.

BRAZIL:

PRÓ-QUÍMICA:

0-800-118270 (Toll-free in Brazil);
For calls originating elsewhere, call: +55-11-232-1144 (Collect calls are accepted).

COLUMBIA:

CISPROQUIM:

01-800-091-6012 in Colombia;
For calls originating in Bogotá, Colombia, call: 288-6012;
For calls originating elsewhere, call: 011-57-1-288-6012.

CANADA:

CANUTEC:

613-996-6666 (Collect calls are accepted);
*666 cellular (in Canada only).

UNITED STATES:

CHEMTREC®:

1-800-424-9300 (Toll-free in the U.S., Canada, and the U.S. Virgin Islands);
703-527-3887 for calls originating elsewhere (Collect calls are accepted).

CHEM-TEL, INC.:

1-800-255-3924 (Toll-free in the U.S., Canada, and the U.S. Virgin Islands);
813-248-0585 for calls originating elsewhere (Collect calls are accepted).

INFOTRAC:

1-800-535-5053 (Toll-free in the U.S., Canada, and the U.S. Virgin Islands);
352-323-3500 for calls originating elsewhere (Collect calls are accepted).

3E COMPANY:

1-800-451-8346 (Toll-free in the U.S., Canada, and the U.S. Virgin Islands);
760-602-8703 for calls originating elsewhere (Collect calls are accepted).

NATIONAL RESPONSE CENTER (NRC):

1-800-424-8802 - (24 hours) (Toll-free in the U.S., Canada, and the U.S. Virgin Islands);
202-267-2675 for calls in the District of Columbia.

MILITARY SHIPMENTS:

703-697-0218 - Explosives/ammunition incidents (Collect calls are accepted);
1-800-851-8061 - All other dangerous goods incidents.

NATIONWIDE POISON CONTROL CENTER (United States only):

1-800-222-1222 (Toll-free in the U.S.).

For additional details see the section entitled "WHO TO CALL FOR ASSISTANCE" under the ERG Instructions.
As an immediate precautionary measure, isolate spill or leak area for at least 100 meters (330 feet) in all directions.
Keep unauthorized personnel away.
Stay upwind.
Many gases are heavier than air and will spread along the ground and collect in low or confined areas (sewers, basements, tanks).
Keep out of low areas.
Ventilate closed spaces before entering.

PUBLIC SAFETY MEASURES - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 120 (ERG, 2004)

CALL Emergency Response Telephone Number on Shipping Paper first. If Shipping Paper not available or no answer, refer to appropriate telephone number:

MEXICO:

SETIQ:

01-800-00-214-00 in the Mexican Republic;
For calls originating in Mexico City and the Metropolitan Area: 5559-1588;
For calls originating elsewhere, call: 011-52-555-559-1588.

CENACOM:

01-800-00-413-00 in the Mexican Republic;
For calls originating in Mexico City and the Metropolitan Area: 5550-1496, 5550-1552, 5550-1485, or 5550-4885;
For calls originating elsewhere, call: 011-52-555-550-1496, or 011-52-555-550-1552; 011-52-555-550-1485, or 011-52-555-550-4885.

ARGENTINA:

CIQUIME:

0-800-222-2933 in the Republic of Argentina;
For calls originating elsewhere, call: +54-11-4613-1100.

BRAZIL:

PRÓ-QUÍMICA:

0-800-118270 (Toll-free in Brazil);
For calls originating elsewhere, call: +55-11-232-1144 (Collect calls are accepted).

COLUMBIA:

CISPROQUIM:

01-800-091-6012 in Colombia;
For calls originating in Bogotá, Colombia, call: 288-6012;
For calls originating elsewhere, call: 011-57-1-288-6012.

CANADA:

CANUTEC:

613-996-6666 (Collect calls are accepted);
*666 cellular (in Canada only).

UNITED STATES:

CHEMTREC®:

1-800-424-9300 (Toll-free in the U.S., Canada, and the U.S. Virgin Islands);
703-527-3887 for calls originating elsewhere (Collect calls are accepted).

CHEM-TEL, INC.:

1-800-255-3924 (Toll-free in the U.S., Canada, and the U.S. Virgin Islands);
813-248-0585 for calls originating elsewhere (Collect calls are accepted).

INFOTRAC:

1-800-535-5053 (Toll-free in the U.S., Canada, and the U.S. Virgin Islands);
352-323-3500 for calls originating elsewhere (Collect calls are accepted).

3E COMPANY:

1-800-451-8346 (Toll-free in the U.S., Canada, and the U.S. Virgin Islands);
760-602-8703 for calls originating elsewhere (Collect calls are accepted).

NATIONAL RESPONSE CENTER (NRC):

1-800-424-8802 - (24 hours) (Toll-free in the U.S., Canada, and the U.S. Virgin Islands);
202-267-2675 for calls in the District of Columbia.

MILITARY SHIPMENTS:

703-697-0218 - Explosives/ammunition incidents (Collect calls are accepted);
1-800-851-8061 - All other dangerous goods incidents.

NATIONWIDE POISON CONTROL CENTER (United States only):

1-800-222-1222 (Toll-free in the U.S.).

For additional details see the section entitled "WHO TO CALL FOR ASSISTANCE" under the ERG Instructions.
As an immediate precautionary measure, isolate spill or leak area for at least 100 meters (330 feet) in all directions.
Keep unauthorized personnel away.
Stay upwind.
Many gases are heavier than air and will spread along ground and collect in low or confined areas (sewers, basements, tanks).
Keep out of low areas.
Ventilate closed spaces before entering.

AIHA ERPG Values for CAS7727-37-9 (AIHA, 2006):

Not Listed

DOE TEEL Values for CAS7727-37-9 (U.S. Department of Energy, Office of Emergency Management, 2010):

Listed as Nitrogen
TEEL-0 (units = ppm): 796000
TEEL-1 (units = ppm): 796000
TEEL-2 (units = ppm): 832000
TEEL-3 (units = ppm): 869000
Definitions:

TEEL-0: The threshold concentration below which most people will experience no adverse health effects.
TEEL-1: The airborne concentration (expressed as ppm [parts per million] or mg/m(3) [milligrams per cubic meter]) of a substance above which it is predicted that the general population, including susceptible individuals, could experience notable discomfort, irritation, or certain asymptomatic, nonsensory effects. However, these effects are not disabling and are transient and reversible upon cessation of exposure.
TEEL-2: The airborne concentration (expressed as ppm or mg/m(3)) of a substance above which it is predicted that the general population, including susceptible individuals, could experience irreversible or other serious, long-lasting, adverse health effects or an impaired ability to escape.
TEEL-3: The airborne concentration (expressed as ppm or mg/m(3)) of a substance above which it is predicted that the general population, including susceptible individuals, could experience life-threatening adverse health effects or death.

AEGL Values for CAS7727-37-9 (National Research Council, 2010; National Research Council, 2009; National Research Council, 2008; National Research Council, 2007; NRC, 2001; NRC, 2002; NRC, 2003; NRC, 2004; NRC, 2004; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; United States Environmental Protection Agency Office of Pollution Prevention and Toxics, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2009; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2008; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2007; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2005; National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances, 2006; 62 FR 58840, 1997; 65 FR 14186, 2000; 65 FR 39264, 2000; 65 FR 77866, 2000; 66 FR 21940, 2001; 67 FR 7164, 2002; 68 FR 42710, 2003; 69 FR 54144, 2004):

Not Listed

NIOSH IDLH Values for CAS7727-37-9 (National Institute for Occupational Safety and Health, 2007):

Not Listed

CONTAINMENT/WASTE TREATMENT OPTIONS

SUMMARY

SPILL OR LEAK PRECAUTIONS - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 121 (ERG, 2004)
- Do not touch or walk through spilled material.
- Stop leak if you can do it without risk.
- Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to conact spilled material.
- Do not direct water at spill or source of leak.
- If possible, turn leaking containers so that gas escapes rather than liquid.
- Prevent entry into waterways, sewers, basements or confined areas.
- Allow substance to evaporate.
- Ventilate the area.
SPILL OR LEAK PRECAUTIONS - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 120 (ERG, 2004)
- Do not touch or walk through spilled material.
- Stop leak if you can do it without risk.
- Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to conact spilled material.
- Do not direct water at spill or source of leak.
- If possible, turn leaking containers so that gas escapes rather than liquid.
- Prevent entry into waterways, sewers, basements or confined areas.
- Allow substance to evaporate.
- Ventilate the area.
- CAUTION: When in contact with refrigerated/cryogenic liquids, many materials become brittle and are likely to break without warning.
RECOMMENDED PROTECTIVE CLOTHING - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 121 (ERG, 2004)
- Wear positive pressure self-contained breathing apparatus (SCBA).
- Structural firefighters' protective clothing will only provide limited protection.
RECOMMENDED PROTECTIVE CLOTHING - EMERGENCY RESPONSE GUIDEBOOK, GUIDE 120 (ERG, 2004)
- Wear positive pressure self-contained breathing apparatus (SCBA).
- Structural firefighters' protective clothing will only provide limited protection.
- Always wear thermal protective clothing when handling refrigerated/cryogenic liquids or solids.
Evaporating a liquid nitrogen spill in a controlled, rapid manner is desirable. Water spray may be used to increase the rate of evaporation in conditions where the increased vapor evolution can be controlled (NFPA, 1986).
- Solid streams of water should NOT be discharged into liquid nitrogen (NFPA, 1986).

WASTE TREATMENT OPTIONS

BIOREMEDIATION

In a laboratory experiment, anaerobic digesters were fed with synthetic wastewaters containing nitrate and nitrite and with glucose as the only carbon source. The study investigated the denitrification potential of anaerobic digesters in the presence of nitrate and nitrite. The results showed that at COD/N-NOx greater than 53, methane was produced without denitrification. At COD/N- NOx less then 8.86, only denitrification took place, and between these values a mixed product was obtained. At COD/N-NOx greater than 53, ammonification was the main NOx reduction pathway (Akunna et al, 1992).
Methane oxidizing bacteria (methanotrophs) were used to remove nutrients from wastewater. Methane was used as the energy source to stimulate bacterial growth with the objective of assimilating nitrogen and phosphorus. The process was used successfully to remove nutrients from secondary sewage effluents from two treatment plants. The process reduced N from 10 to 15 mg/L to less than 1 mg/L, and P from 1 to 1.8 mg/L to less than 0.1 mg/L (Jewell et al, 1992).
Nitrosomonas europaea is an ammonia oxidizing species used for nitrification of ammonia in concentrated waste streams. Substrate and product concentrations were monitored in this study up to 500 moles per liter and at pHs ranging from 6.5 to 8.5. The results showed that high ionic concentrations inhibit the organism, but no specific substrate inhibition was noted. Product inhibition was found to be strongly pH dependent and had a maximum at pH 6.5 (Hunik et al, 1992).
Two soil microalgae, Chlorella vulgaris and Scenedesmus bijugatus, were entrapped in 4-mm calcium-alginate beads and used in continuous flow cultures to determine the efficiency of removal of ammoniacal-nitrogen (N) and orthophosphate-phosphorus (P). Higher cell density removed 71 to 79% more N and 52 to 82% more P within 6 hours than cultures with low cell density. C. vulgaris more efficiently removed both nutrients than S. bijugatus (Megharaj et al, 1992).
Pilot studies in sewage treatment lagoons showed that the best way to improve nitrogen removal is to promote nitrification. Laboratory tests showed that biofilm-coated plates nitrified more efficiently than tanks containing suspended microbial solids. The results, with 2 to 3 mg/L of dissolved oxygen, were near 30% of the ammonia-nitrogen fed to the reactor was denitrified (Baskaran et al, 1992).
A two-stage anaerobic-aerobic treatment was applied to high concentration industrial wastewaters. The new process method completed nitrification/denitrification via a nitrite intermediate. Ammonia concentration in the reactor was the key operation parameter. Ammonia concentrations between 1 to 5 mg/L inhibited the nitration step, but not the nitritation process. The ammonia concentration was controlled by monitoring the pH of the treated solution (Abeling & Seyfried, 1992).
A Swedish wastewater treatment plant uses pre-precipitation of phosphorus with ferric chloride and denitrification with methanol as the carbon source. The process requires only a small tank volume, but an increased need for process monitoring to insure successful operation. The process used on-line monitoring of ammonia, nitrogen and TOC for control and optimization. The monitored parameters are use in a mathematical model of the process that provides a long term strategic planning function for the process (Aspegren et al, 1992).
Nitrogen and phosphorus were removed from wastewater by a multi-soil-layering method.
- Layers of soil were mixed with 10 to 25% metal iron and pelletized jute. A layer of zeolite was positioned around the soil layers and provision made for aeration.
- Water purification was controlled by the degree of aeration (Wakatsuki et al, 1993).
A biofilter made of wheat straw removed 50% of the ammonia, 65% of the suspended solids and 75% of the algal biomass from the input water. The biofilter has a minimum capacity of 2 m(3) water per kg of straw (Avnimelech at al, 1993).
Control of mixed liquor pH (MLpH) with calcium hydroxide and sodium bicarbonate enhanced the metabolic activity and digester efficiency in a semi-continuous aerobic digester. MLpH control increased removal of both nitrogen and phosphorus (Anderson & Mavinic, 1993).
An intermittent aeration process (IAP) was more efficient than a continuous aeration process for removing nitrogen (N) and phosphorus (P) in methane fermentation with activated sludge and pig slurry. Up to 70% of the N and 42% of the P were removed in the IAP (Liao et al, 1993).
Thiobacillus denitrificans is able to complete denitrification reaction by using sulfide as an electron donor. In the anoxic chamber of a wastewater treatment pilot plant, the organism reduced nitrate to nitrogen gas and oxidized sulfide to sulfate (Yang et al, 1993).
A simple oxidation ditch system proved to be very effective for biological wastewater treatment for removal of BOD related nitrogen and phosphorus. An optimized ditch process could reduce the effluent BOD to less than 15 mg/L, including 8 mg/L nitrogen and 1.5 mg/L phosphorus (Petersen et al, 1993).
Waste management activities associated with material disposition are unique to individual situations. Proper waste characterization and decisions regarding waste management should be coordinated with the appropriate local, state, or federal authorities to ensure compliance with all applicable rules and regulations.

PHYSICAL TREATMENT

A 62-L hollow fiber membrane bioreactor was used to evaluate nitrogen removal from wastewater. The degree of nitrification depended on the amount of dissolved oxygen concentration in the mixed liquid during aeration. The nitrogen removal rate was greater than 90% at an aeration rate of 4 to 5 mg/L (Chiemchaisri et al, 1992).

-ENVIRONMENTAL HAZARD MANAGEMENT

POLLUTION HAZARD

The dissolved organic nitrogen concentration in the Northern Pacific showed a vertical profile: from 0 to 100 meters the concentration was between 10 and 12 mcg atoms N/L, and at greater depths the concentration ranged between 6 and 8 mcg/L (Koike & Tupas, 1993).

The salinity (of sea water) was monitored in coastal areas to determine the effect of nitrogen starvation on the tissue nitrogen concentration of salt marsh grass Spartina alterniflora Loisel. The results suggest that the critical nitrogen concentration is a function of salinity and that both tall and short forms of the grass are nitrogen limited in marshes along the Gulf and Atlantic Coasts of the United States (Bradley & Morris, 1992).

Nitrogen concentration was measured in a tundra stream in Alaska in 1980. Nitrate concentrations were inversely correlated with stream flow rates in an Alaskan tundra stream, measured in 1980 (Peterson et al, 1992).

The concentrations of nitrogen (N) and phosphorus (P) were monitored in two lakes and two rivers in the Parana River floodplain of Argentina. The data show that floodplain waterbodies were efficient traps for suspended matter, total phosphorus and inorganic nitrogen. The phosphorus precipitated and became available for plant growth after deoxygenation while the nitrogen was lost through denitrification causing the observed nitrogen limitation in these systems (Pedrozo et al, 1992).

Mixing the water in fish ponds reduces the anaerobic zones in the water, promotes efficient nitrification, and minimizes ammonia accumulation in the water (Avnimelech et al, 1992).

Twenty-seven to 28% of the total nitrogen input to a Swedish trout farm was recovered in harvested fish, fish loss accounted for between 2 and 5%, with the remaining 67 to 71% loss to the aquatic environment (AH Hall , 1992).

The nitrate concentration in certain sand plain aquifers in central Minnesota are above the national drinking-water standards (10 mg/L as N). Commercial inorganic fertilizers exist in the ground water beneath all the land areas sampled except feedlots (Komor & Anderson, 1993).

Test plots were fertilized with nitrogen at a rate of 200 to 480 kg/ha/year. Water draining from the plots over a four year period contained between 10 and 56 mg/L nitrate and a total nitrogen loss of less than 5 kg/ha/year (Thome et al, 1993).

The phytoplankton communities in Lake Apopka, Florida were exposed to varying nutrient enrichment regimes containing nitrogen (N) and phosphorus (P). Nitrogen was the primary limiting nutrient in most experiments because the lake contained natural excess P loading (Aldridge et al, 1993).

Photolithotropic, nonheterocystonous cyanobacteria were identified as the dominant organism in a microbial mat community. These bacteria were the principal source of nitrogen fixation in the mats. The bacteria used storage products of oxygenic photosynthesis at night (Bebout et al, 1993).

Nitrogen fixation rates were reduced in intertidal microbial mats in Tomales Bay (CA) in response to inorganic nitrogen-enriched runoff. Denitrification rates increased by an ordered of magnitude responding to the same runoff effect (Joye & Paerl, 1993).

Massive growth of phytoplankton biomass throughout a dam reservoir supplying drinking water to the Prague Agglomeration caused deterioration of water quality. The biomass growth was caused by an unwanted supply of phosphorus and nitrogen compounds from polluted watersheds (Chour et al, 1993).

A greenhouse experiment was done to determine the distribution and leach potential of various nitrogen (N) loading and two N sources. The N loading rates were 0, 84 and 168 kg/ha and the sources were (NH4)2SO4 and NH4NO3. The experiments were done in soil columns to which water was added every 4 days and the effluent collected twice a week for 3 months. The results showed that the highest N recovery was at the 84 kg/ha loading and with ammonium sulfate. The nitrate-N concentration averaged 0-0.2 mg/L, much lower than the USEPA water quality standard of 10 mg/L (Sveda et al, 1992).

In defined laboratory experiments the rates of transformation of both fertilizer and soil nitrogen (N) were measured in three soils labelled with N-15. Three nitrification inhibitors were applied to the soils in water solution, as an emulsion, or in one of three solvents (water, ethanol, acetone). The inhibitors had little effect on N transformation rates. The results showed that these inhibitors and solvents had only a transient effect on biological transformations of N in soils in the absence of growing plants (Crawford & Chalk, 1992)

Production and consumption of nitric oxide (NO) was measured under anaerobic condition in soils at 80% water-holding capacity and flushed continuously with nitrogen. When nitrate or nitrite was not present both production and consumption of NO was negligible. The results indicated that nitrite or nitrate was the limiting factor for both reactions (Baumgartner & Conrad, 1992).

A combination laboratory and field study was done to evaluate the nitrogen (N) mineralization of soil samples. The results showed a negative correlation between the mineral N content at the start of the experiment and the mineral N produced. A negative relationship was observed between mineralization rates of consecutive incubation periods with a lower production in the second period. This result suggest a feedback mechanism related to the mineralization-immobilization process in soil microsites and indicates a very complex micro-level process (Sierra, 1992).

Three new bacteria strains were isolated from the rhizosphere of mangrove trees. Two of the bacteria were diazotrophic and the third was a non-nitrogen-fixing bacterium of the Staphylococcus species. The diazotrophs are from a family of bacteria known to be pathogenic to fish and shellfish. The staphylococcus sp. bacterium when used in mixed culture with one of the diazotrophs, increased the nitrogen-fixing capacity by 17% over the pure culture. The same reaction with the other isolate resulted in a decrease in nitrogen-fixing capacity of about 15% (Holguin et al, 1992).

Microbial growth was more limited by N than P in forest soil, and microbially available N was 6.3 to 18.5 times higher than the KCl extractable N (Nordgren, 1992).

Laboratory studies showed a linear relationship between moisture content (between 10 and 290% ODW) and nitrification in coniferous forest litter.

Nitrification was shown to have a negative linear correlation with the H-ion concentration in the range 0.04 (pH 4.40) and 0.36 (pH 3.45) mmol H-ion per liter. At pH lower than 3.45 no nitrate was produced.

There was no relationship between net mineralization and pH (Tietema et al, 1992).

A large sand-filled lysimeter was constructed to quantify five year nitrogen budgets for two nitrogen fixing trees, two pines, and a nonvegatative control soil.

Gains in net nitrogen accumulation in pine systems were greatest in litter and vegetation, outpacing loses from leaching and mineral soil by a factor of three.

Pine trees with rhisopheres that fix nitrogen at high rates might be used to restore degraded land and create a silvaculture system that is nitrogen self sufficient (Bormann et al, 1993).

N2O accounted for 70 to 90% of gaseous nitrogen loss in the upland forests, while it accounted for only 25% of the nitrogen loss in a swamp forest. Nitrate availability was the controlling factor in the swamp ecosystem denitrification rate, while soil water content was the controlling factor in the upland forests (Merrill & Zak, 1992).

A closed infrared gas exchange system was used to measure soil carbon dioxide (CO2) flux in a peatland area of north central Minnesota.

The soil CO2 flux was highly temperature dependent and was found to have a linear relationship with the water table depth. Between May and October, the total soil CO2 released from the study ecosystem was about 1340 grams per square meter (Kim & Verma, 1992).

The Old Woman Creek National Estuarine Research Reserve (OWC) was the sight of the most comprehensive investigation of nitrogen (N) and phosphorus (P) dynamics in the Great Lakes coastal wetlands.

This wetland is a nutrient sink, storing P in sediments and releasing N by denitrification.

The wetland biotic community transforms inorganic N and P into organic dissolved and particulate matter that may alter nutrient availability to the lake (Heath, 1992).

In contrast to results from other studies, nitrogen and phosphurus were both required for growth and biomass accumulation in an estuarine population of eelgrass (Murray et al, 1992).

Over a 15 month period, microbial and chemical assays were done on clay soils from woodlands, grasslands and croplands in Australia. The level of biomass microbial nitrogen (N) was measured at 5745 mcg N/g in woodland soil and was 41% and 270% higher than in pasture and cropped soils, respectively. The results suggested that leaching may play an important role in the distribution of plant available nitrogen (Grace et al, 1992).

There are two different, sometime opposing, measures for the amount of mineral Nitrogen (N) left in the soil at harvest time: the Maximum Economic Yield (MEY) and the Environmental Acceptable Production (EAP). A model was developed to simulate the fertilizer experiments and evaluate the effects of spatial variability on the N balance. The model showed that spacial variability of mineral N in the soil leads to higher 'economic optimum' fertilizer rates, while allowing for decreased EAP. Without spatial variability a positive difference of 13 kg per ha exists between N fertilizer rates for EAP and MEY (Vannoordwijk & Wadman, 1992).

The fate of nitrogen fertilizers beneath agricultural fields and the subsequent increase in nitrates in groundwater was the subject of this study. Advective-dispersive transport moves nitrate through unsaturated and saturated soils. The data suggest that denitrification potential is greater beneath the bottom slope than the top slope. The data show that large masses of nitrate reside in deep subsoil zones that should be monitored to detect future groundwater quality treats (Geyer et al, 1992).

Drying and rewetting soils increased the background nitrogen mineralization rate and suggested that the cycling between wet and dry states facilitates transfer of nitrogen from a first order pool to a zero-order pool (Cabrera, 1993).

A large data bank of Russian literature concerning accumulation, transformation, and release of nitrogen and phosphorus compounds into lakes and reservoirs was analyzed and reported. Sediment nitrogen accumulation was mainly (greater than 90%) in organic form and came from phytoplankton or macrophytes (Martinova, 1993).

Amoebae were shown to play an active role in nitrogen mineralization in soils due to their consumption of several microorganism (eg, algae, yeast, and bacteria). Amoebae have a high nitrogen metabolic capacity (Weekers & Vanderdrift, 1993).

Nitrogen-fixation in soils is carried out by microorganisms containing an enzyme nitrogenase. Soils containing earthworms have a high natural nitrogenase activity. Soil treated with pesticides or contaminated with heavy metals have little natural nitrogenase activity (Simek, 1993).

ARRAIAL CABO DE TONI (KUTZING): Light was found to be a growth controlling factor for the macroalga, Kutzing. Nitrogen was limiting only at conditions of light saturation (Coutinho & Zingmark, 1993).

Coffea arabica L was grown in a shaded greenhouse and treated with nitrogen (N) doses of 0, 1, 2 mmol for 4 weeks. Exposed to full solar radiation plants without N showed visible damage in 2 days. Seventy percent of the N treated plants survived 130 days in sunlight, none of the untreated plants survived (Nunes et al, 1993).

There is a strong inverse relationship between the annual rate of nitrogen fixation and nitrogen content of the soil ecosystem.

Application of phosphorus fertilizer modifies this relationship by influencing the activity of nitrogen fixing organisms. Phosphorus availability seems to be an important regulator in nitrogen biogeochemistry (Smith, 1992).

Azotobacter and Azospirillum are two genera of nitrogen-fixing bacteria that have been used as nitrogenous fertilizers. When used with crops such as tomatoes, potatoes and sugar beets, they produce increased crop yields.

Using these nitrogen-fixing bacteria substantially increases the yield of many agricultural products and eliminates the need for nitrogenous fertilizers (Martin et al, 1993).

Algae and macrophytes reflect the nitrogen and phosphorus in lake water. Bioassays showed nitrogen to be the important limiting nutrient, although phosphorus under some conditions was also found to be limiting (Carney et al, 1993).

Two cyanobacteria, Trichodesmium thiebaurii and T. erythraeum, were monitored in the Caribbean Sea and found to have a doubling rate between 3 and 3.8 days. T. thiebautii has a higher abundance in this area due to a higher rate of nitrogen fixation than T. erythraeum (Carpenter et al, 1993).

Phytoplankton production in the surface waters of the oceans is fed mainly by nitrogen recycled within the euphotic zone. Rhizosolenia mats transport about 50% of the nitrogen requirements into the surface waters of the North Pacific gyre from deep nitrate pools (Villareal et al, 1993).

Nitrogen supply was monitored in blue-green and green algae from subarctic and Arctic Alaska freshwater lakes. Nitrogen-fixing algae showed higher nitrogen content (7.1%) than non-nitrogen-fixing algae (2.9%). Isotope ratio methods showed that A. flos-aquae obtained 58 to 75% of its nitrogen by nitrogen-fixation (Gu & Alexander, 1993).

Higher nitrate removal rates were found in streams polluted by readily degradable organic matter than in a stream feed by groundwater. The rate of nitrate removal increased with higher initial nitrate concentration (Faafeng & Roseth, 1993).

ENVIRONMENTAL FATE AND KINETICS

OTHER

OTHER
- SOIL

ENVIRONMENTAL TOXICITY

Nitrogen is not harmful to aquatic life (CHRIS , 1985).

-PHYSICAL/CHEMICAL PROPERTIES

MOLECULAR WEIGHT

Nitrogen gas 28.02 (Sax & Lewis, 1996)

DESCRIPTION/PHYSICAL STATE

Nitrogen exists in a liquid phase between minus 209.86 degrees Celsius (melting point) and minus 195 degrees Celsius (boiling point) (Rockswold & Buran, 1982).

Nitrogen gas is colorless, odorless, and tasteless (Sax & Lewis, 1996).

VAPOR PRESSURE

At normal temperatures is approximately the same as air (air = 1) (NFPA, 1986)

DENSITY

STANDARD TEMPERATURE AND PRESSURE

(0 degrees C; 32 degrees F and 760 mmHg)
GAS: 1.2506 g/L (Sax & Lewis, 1996)

FREEZING/MELTING POINT

FREEZING POINT

-215 degrees C; -354 degrees F (CHRIS , 1985)

MELTING POINT

-210.0 degrees C (Sax & Lewis, 1989)

BOILING POINT

-195.6 degrees C; -320 degrees F (NFPA, 1986; (CHRIS , 1985).

SOLUBILITY

IN WATER

Nitrogen is slightly soluble in water (AAR, 1987; Sax & Lewis, 1989).

IN ORGANIC SOLVENTS

Nitrogen is soluble in alcohol and liquid ammonia (Sax & Lewis, 1989).

HENRY'S CONSTANT

8.6 X 10(4) atm (at 20 degrees C) (Corbitt, 1990)

OTHER/PHYSICAL

ODOR THRESHOLD

Odorless (CHRIS , 2002)

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Classification | Information to evaluate chemical incidents

Information to evaluate chemical incidents

Information to evaluate chemical incidents

Information to evaluate chemical incidents