UN/NA Number Reference
DOT Class 6.1 Toxic Substance placard

UN 2279: Hexachlorobutadiene

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 2279 is assigned the proper shipping name Hexachlorobutadiene in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 6.1 Toxic Substance material, Packing Group III. Required label(s): 6.1.

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 151)

Hazards: TOXIC. May be fatal if inhaled, ingested, or absorbed through skin. Contact may cause burns.

Fire: Use agent appropriate for surrounding fire. Cool containers with water.

Spill: Do not touch. Avoid inhalation. Use water spray to reduce dust/vapor. Ventilate.

Chemical and Physical Properties

Hexachlorobutadiene appears as a colorless liquid with a mild odor. Insoluble in water and denser than water. Nonflammable. May be toxic by ingestion or inhalation. Used as a solvent and heat transfer fluid.

CAS Number: 87-68-3
Molecular Formula: C4Cl6
Molecular Weight: 260.8 g/mol
Color / Form: Clear, colorless liquid
Odor: Mild, turpentine-like odor.
Boiling Point: 419 F
Melting Point: -6 °F (NTP, 1992)
Flash Point: 90 C
Autoignition: 1130 °F (USCG, 1999)
Specific Gravity: 1.675 (sinks in water)
Vapor Pressure: 0.15 mmHg at 68 F
Vapor Density: 8.99 (heavier than air)
Water Solubility: less than 0.1 mg/mL at 72 F
Log P: log Kow = 4.78

Regulatory Data

CERCLA RQ (40 CFR 302.4)
1 lb
OSHA PEL
none
NIOSH REL
Ca TWA 0.02 ppm (0.24 mg/m 3 ) [skin]
IDLH
Ca [N
RCRA Waste Code(s)
[object Object], [object Object]

A release of this material at or above its CERCLA reportable quantity (1 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: IB3, T4, TP1. 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.

Need the full interactive record? Open UN 2279 in the SpillNerd lookup tool for the live database entry with placard graphics, GHS pictograms, full segregation tables, and synonym search. For another material, use the UN number and chemical lookup.

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.