UN/NA Number Reference
DOT Class 5.1 Oxidizer placard

UN 1439: Ammonium dichromate

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1439 is assigned the proper shipping name Ammonium dichromate in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 5.1 Oxidizer material, Packing Group II. Required label(s): 5.1.

Packing group indicates the degree of danger within a hazard class: PG I is high danger, PG II medium, PG III low. The proper shipping name, hazard class, UN number, and packing group together form the basic shipping description that must appear on shipping papers and, where required, on the package and placard.

Emergency Response (ERG Guide 141)

Hazards: Oxidizer. TOXIC. May be fatal if inhaled or swallowed. Accelerates combustion.

Fire: Use flooding water. Do not use dry chemical, foam.

Spill: Do not touch. Keep combustibles away. Use water spray.

Chemical and Physical Properties

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.

CAS Number: 7789-09-5
Molecular Formula: Cr2H8N2O7
Molecular Weight: 252.07 g/mol
Color / Form: Bright orange-red monoclinic prisms
Odor: Odorless
Melting Point: Decomposes 180 °C
Autoignition: 437 °F (USCG, 1999)
Specific Gravity: 2.15 (sinks in water)
Water Solubility: 35.6 g/100 g water at 20 C
pH: 1% solution has pH of 3.95; 10% solution has pH of 3.45

Regulatory Data

CERCLA RQ (40 CFR 302.4)
10 lb

A release of this material at or above its CERCLA reportable quantity (10 lb) requires immediate notification to the National Response Center at 800-424-8802.

Special Provisions

49 CFR 172.102 special provision codes for this entry: IB8, IP2, IP4, T3, TP33. These codes modify the general requirements (packaging, quantity limits, exceptions) for this specific material. Look up each code in 49 CFR 172.102 for the full text.

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Reference data compiled from the DOT Hazardous Materials Table (49 CFR 172.101), the 2024 Emergency Response Guidebook, and public chemical databases (PubChem, NIOSH, EPA). Always verify the correct shipping description against the current regulation and the manufacturer's SDS Section 14 before shipping.