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AMMONIUM DICHROMATE

5.1 - Oxidizer
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The Chemical Identifier fields include common identification numbers, the NFPA diamond U.S. Department of Transportation hazard labels, and a general description of the chemical. The information in CAMEO Chemicals comes from a variety of data sources.
CAS Number UN/NA Number
  • 7789-09-5
DOT Hazard Label USCG CHRIS Code
  • Oxidizer
NIOSH Pocket Guide International Chem Safety Card
Chromic acid and chromatesexternal_link
NFPA 704
Diamond Hazard Value Description
1
2 1
ox
Blue Health 2 Can cause temporary incapacitation or residual injury.
Red Flammability 1 Must be preheated before ignition can occur.
Yellow Instability 1 Normally stable but can become unstable at elevated temperatures and pressures.
White Special OX Possesses oxidizing properties.
(NFPA, 2010)
General Description
Ammonium dichromate is a bright orange red crystalline solid. It is readily ignited and burns producing a voluminous green residue. If heated in a closed container, the container may rupture due to the decomposition of the material. It may also act as a strong oxidizing agent if mixed with or contaminated with combustible material. It is soluble in water.

The Hazard fields include special hazard alerts air and water reactions, fire hazards, health hazards, a reactivity profile, and details about reactive groups assignments and potentially incompatible absorbents. The information in CAMEO Chemicals comes from a variety of data sources.
Reactivity Alerts
  • Explosive
  • Strong Oxidizing Agent
Air & Water Reactions
Water soluble.
Fire Hazard
Special Hazards of Combustion Products: Greenish chromic oxide smoke may cause irritation of lungs and mucous membranes.

Behavior in Fire: Decomposes at about 180°C. Decomposition self-sustaining at about 225°C with spectacular swelling and evolution of heat and nitrogen, leaving chromic oxide residue. Pressure of confined gases can burst closed containers explosively. (USCG, 1999)
Health Hazard
Inhalation causes irritation or ulceration of the mucous membranes of the nose, throat or respiratory tract. Respiratory irritation can produce symptoms resembling those of asthma. Continuing irritation of the nose may lead to perforation of the nasal septum. External contact can cause eye irritation and conjunctivitis, irritation and ulceration of skin wounds, and rash or external ulcers. If ingested, irritates mucous membrane and causes vomiting. (USCG, 1999)
Reactivity Profile
It is an oxidizing reagent, it readily reacts with reducing materials, in large quantity it may produce a violent reaction. Direct exposure to heat or shock will explode it. When heated to decomposition it emits toxic fumes of ammonia and nitrogen oxides [Sax, 9th ed., 1996, p. 205].
Belongs to the Following Reactive Group(s)
Potentially Incompatible Absorbents

Use caution: Liquids with this reactive group classification have been known to react with the absorbents listed below. More info about absorbents, including situations to watch out for...

  • Cellulose-Based Absorbents
  • Expanded Polymeric Absorbents

The Response Recommendation fields include isolation and evacuation distances, as well as recommendations for firefighting, non-fire response, protective clothing, and first aid. The information in CAMEO Chemicals comes from a variety of data sources.
Isolation and Evacuation
Excerpt from ERG Guide 141 [Oxidizers - Toxic]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

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

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)
Firefighting
Excerpt from ERG Guide 141 [Oxidizers - Toxic]:

SMALL FIRE: Use water. Do not use dry chemicals or foams. CO2 or Halon® may provide limited control.

LARGE FIRE: Flood fire area with water from a distance. Do not move cargo or vehicle if cargo has been exposed to heat. If it can be done safely, move undamaged containers away from the area around the fire.

FIRE INVOLVING TANKS OR CAR/TRAILER LOADS: 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. 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)
Non-Fire Response
Excerpt from ERG Guide 141 [Oxidizers - Toxic]:

Keep combustibles (wood, paper, oil, etc.) away from spilled material. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk.

SMALL DRY SPILL: With clean shovel, place material into clean, dry container and cover loosely; move containers from spill area.

LARGE SPILL: Dike far ahead of spill for later disposal. (ERG, 2020)
Protective Clothing
Dust respirator; protective goggles, gloves, clothing. (USCG, 1999)
DuPont Tychem® Suit Fabrics
No information available.
First Aid
INHALATION: remove to clean air and summon medical attention.

EYES: immediately flush with water for at least 15 min. and consult a physician.

SKIN: flush with water; if skin irritation develops, get medical attention.

INGESTION: vomiting should occur; follow with an emetic of soapy water; give large amounts of water. (USCG, 1999)

The Physical Property fields include properties such as vapor pressure and boiling point, as well as explosive limits and toxic exposure thresholds The information in CAMEO Chemicals comes from a variety of data sources.

Note: For Vapor Density and Specific Gravity, comparing the value to 1.0 can tell you if the chemical will likely sink/rise in air or sink/float in fresh water (respectively). Short phrases have been added to those values below as an aid. However, make sure to also consider the circumstances of a release. The Vapor Density comparisons are only valid when the gas escaping is at the same temperature as the surrounding air itself. If the chemical is escaping from a container where it was pressurized or refrigerated, it may first escape and behave as a heavy gas and sink in the air (even if it has a Vapor Density value less than 1). Also, the Specific Gravity comparisons are for fresh water (density 1.0 g/mL). If your spill is in salt water (density about 1.027 g/mL), you need to adjust the point of comparison. There are some chemicals that will sink in fresh water and float in salt water.
Chemical Formula:
  • (NH4)2Cr2O7
Flash Point: data unavailable
Lower Explosive Limit (LEL): data unavailable
Upper Explosive Limit (UEL): data unavailable
Autoignition Temperature: 437°F (USCG, 1999)
Melting Point: data unavailable
Vapor Pressure: data unavailable
Vapor Density (Relative to Air): data unavailable
Specific Gravity: 2.15 at 77°F (USCG, 1999) - Denser than water; will sink
Boiling Point: data unavailable
Molecular Weight: 252.06 (USCG, 1999)
Water Solubility: data unavailable
Ionization Energy/Potential: data unavailable
IDLH: 15 mg Cr(VI)/m3 ; A potential occupational carcinogen. (NIOSH, 2023)

AEGLs (Acute Exposure Guideline Levels)

No AEGL information available.

ERPGs (Emergency Response Planning Guidelines)

No ERPG information available.

PACs (Protective Action Criteria)

Chemical PAC-1 PAC-2 PAC-3
Ammonium dichromate (7789-09-5) 0.37 mg/m3 6.3 mg/m3 38 mg/m3
(DOE, 2018)

The Regulatory Information fields include information from the U.S. Environmental Protection Agency's Title III Consolidated List of Lists, the U.S. Cybersecurity and Infrastructure Security Agency's Chemical Facility Anti-Terrorism Standards, and the U.S. Occupational Safety and Health Administration's Process Safety Management of Highly Hazardous Chemicals Standard List (see more about these data sources).

EPA Consolidated List of Lists

Regulatory Name CAS Number/
313 Category Code
EPCRA 302
EHS TPQ
EPCRA 304
EHS RQ
CERCLA RQ EPCRA 313
TRI
RCRA
Code
CAA 112(r)
RMP TQ
Ammonium bichromate 7789-09-5 10 pounds 313c
Chromium Compounds N090 & 313

(EPA List of Lists, 2022)

CISA Chemical Facility Anti-Terrorism Standards (CFATS)

No regulatory information available.

OSHA Process Safety Management (PSM) Standard List

No regulatory information available.

This section provides a listing of alternate names for this chemical, including trade names and synonyms.
  • AMMONIUM BICHROMATE
  • AMMONIUM CHROMATE ((NH4)2CR2O7)
  • AMMONIUM DICHROMATE
  • AMMONIUM DICHROMATE(VI)
  • DIAMMONIUM DICHROMATE
  • DICHROMIC ACID (H2CR2O7), DIAMMONIUM SALT

Version 3.0.0