NITRIC OXIDE AND NITROGEN TETROXIDE MIXTURE

Diamond	Hazard	Value	Description
0 3 0 ox	Health	3	Can cause serious or permanent injury.
	Flammability	0	Will not burn under typical fire conditions.
	Instability	0	Normally stable, even under fire conditions.
	Special	OX	Possesses oxidizing properties.

A reddish brown gas which becomes a yellowish-brown liquid on cooling or compressing. Shipped as a liquefied gas under own vapor pressure. Vapor heavier than air. Toxic by inhalation and skin absorption. Noncombustible but accelerates burning of combustible materials. Cylinders and ton containers may not be equipped with a safety relief device.

• Strong Oxidizing Agent
• Water-Reactive
• Air-Reactive

Combines with oxygen to form nitrogen dioxide, a brown gas that is deadly poisonous [Merck 11th ed. 1989]. Decomposes in water to form nitric acid and nitric oxide, reacts with alkalis to form nitrate and nitrites [Merck 11th ed.1989].

Excerpt from 124 [Gases - Toxic and/or Corrosive - Oxidizing]:

Substance does not burn but will support combustion. Vapors from liquefied gas are initially heavier than air and spread along ground. These are strong oxidizers and will react vigorously or explosively with many materials including fuels. May ignite combustibles (wood, paper, oil, clothing, etc.). Some will react violently with air, moist air and/or water. Cylinders exposed to fire may vent and release toxic and/or corrosive gas through pressure relief devices. Containers may explode when heated. Ruptured cylinders may rocket. (ERG, 2020)

Excerpt from 124 [Gases - Toxic and/or Corrosive - Oxidizing]:

TOXIC; may be fatal if inhaled or absorbed through skin. Fire will produce irritating, corrosive and/or toxic gases. Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Runoff from fire control or dilution water may cause environmental contamination. (ERG, 2020)

Liquid nitrogen dioxide (dinitrogen tetraoxide) was fed into a nitration column containing hot cyclohexane, due to an error. An explosion resulted [MCA Case History 128. 1962]. The slow reaction between nitrogen dioxide and formaldehyde becomes explosive when it is near 180°C [Trans. Faraday Soc. 45:767-770. 1949]. Manganese or potassium ignites in nitrogen dioxide (Ann. Chem. et Phys.(2) 2:317). Nitrogen dioxide and ozone react with the evolution of light and often explode [J. Chem. Phys. 18:366. 1920]. Contact of very cold liquefied gas with water may result in vigorous or violent boiling of the product and extremely rapid vaporization due to the large temperature differences involved. If the water is hot, there is the possibility that a liquid "superheat" explosion may occur. Pressures may build to dangerous levels if liquid gas contacts water in a closed container [Handling Chemicals Safely 1980].

• Oxidizing Agents, Strong

Use caution: Liquids with this reactive group classification have been known to react with the absorbents listed below.

• Cellulose-Based Absorbents
• Expanded Polymeric Absorbents

Excerpt from 124 [Gases - Toxic and/or Corrosive - Oxidizing]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 100 meters (330 feet) in all directions.

SPILL: See ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 1975 datasheet.

FIRE: 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. (ERG, 2020)

Excerpt from 124 [Gases - Toxic and/or Corrosive - Oxidizing]:

SMALL FIRE: CAUTION: These materials do not burn but will support combustion. Some will react violently with water. Contain fire and let burn. If fire must be fought, water spray or fog is recommended. Water only; no dry chemical, CO2 or Halon®. Do not get water inside containers. If it can be done safely, move undamaged containers away from the area around the fire. Damaged cylinders should be handled only by specialists.

FIRE INVOLVING TANKS: Fight fire from maximum distance or use unmanned master stream devices 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. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn. (ERG, 2020)

Excerpt from 124 [Gases - Toxic and/or Corrosive - Oxidizing]:

Do not touch or walk through spilled material. Keep combustibles (wood, paper, oil, etc.) away from 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 contact 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. Isolate area until gas has dispersed. Ventilate the area. (ERG, 2020)

Excerpt from ERG Guide 124 [Gases - Toxic and/or Corrosive - Oxidizing]:

Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer when there is NO RISK OF FIRE. Structural firefighters' protective clothing provides thermal protection but only limited chemical protection. (ERG, 2020)

Normalized Breakthrough Times (in Minutes)

Chemical	CAS Number	State	QS	QC	SL	C3	TF	TP	RC	TK	RF
Nitric oxide	10102-43-9	Vapor								>480
Nitrogen tetroxide	10544-72-6	Liquid							>480	>480	>480
Nitrogen tetroxide (21°C, liquid)	10544-72-6	Liquid								450
Nitrogen tetroxide (gaseous)	10544-72-6	Vapor							90	90	90

Special Warning from DuPont: Tychem® and Tyvek® fabrics should not be used around heat, flames, sparks or in potentially flammable or explosive environments. Only...

(DuPont, 2023)

Excerpt from 124 [Gases - Toxic and/or Corrosive - Oxidizing]:

Call 911 or emergency medical service. Ensure that medical personnel are aware of the material(s) involved and take precautions to protect themselves. Move victim to fresh air if it can be done safely. Give artificial respiration if victim is not breathing. Do not perform mouth-to-mouth resuscitation if victim ingested or inhaled the substance; wash face and mouth before giving artificial respiration. Use a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult. Clothing frozen to the skin should be thawed before being removed. Remove and isolate contaminated clothing and shoes. In case of contact with substance, immediately flush skin or eyes with running water for at least 20 minutes. Keep victim calm and warm. Keep victim under observation. Effects of contact or inhalation may be delayed. (ERG, 2020)

• NITRIC OXIDE AND NITROGEN TETROXIDE MIXTURE
• NITRIC OXIDE-NITROGEN TETROXIDE MIXTURE
• NITROGEN TETROXIDE AND NITRIC OXIDE MIXTURE