UN/NA Number Reference

UN 2809: Mercury

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 2809 is assigned the proper shipping name Mercury in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 8 Corrosive material, Packing Group III. Required label(s): 8, 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 172)

Hazards: Liquid metals. May be harmful if inhaled or absorbed. Mercury vapor is toxic. Corrosive to aluminum.

Fire: Use agent for surrounding fire. Mercury does not burn. Cool containers.

Spill: Do not touch. Mercury: use special mercury spill kit. Prevent from entering drains.

Chemical and Physical Properties

Mercury appears as an odorless, silvery metallic liquid. Insoluble in water. Toxic by ingestion, absorption and inhalation of the fumes. Corrosive to aluminum. Used as a catalyst in instruments, boilers, mirror coatings.

CAS Number: 7439-97-6

Molecular Formula: Hg

Molecular Weight: 200.59 g/mol

Color / Form: Silver-white, heavy, mobile, liquid metal; solid mercury is tin-white

Odor: Odorless

Boiling Point: 675 F

Melting Point: -38 °F (USCG, 1999)

Autoignition: Not flammable (USCG, 1999)

Specific Gravity: 13.55 (sinks in water)

Vapor Pressure: 0.0012 mmHg

Vapor Density: 6.93 (heavier than air)

Water Solubility: Insoluble

Regulatory Data

CERCLA RQ (40 CFR 302.4)

1 lb

OSHA PEL

See Annotated Z-2 See Annotated Z-2 MERCURY, ALL FORMS EXCEPT ALKYL - ACGIH

NIOSH REL

NIOSH REL: Hg Vapor: TWA 0.05 mg/m 3 [skin] Other: C 0.1 mg/m 3 [skin]

IDLH

10 mg/m 3 (as Hg)

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: 365. 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 2809 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.