UN/NA Number Reference
DOT Class 4.1 Flammable Solid placard

UN 2538: Nitronaphthalene

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 2538 is assigned the proper shipping name Nitronaphthalene in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 4.1 Flammable Solid material, Packing Group III. Required label(s): 4.1.

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 133)

Hazards: Flammable. May be ignited by friction, heat, sparks. May burn rapidly with flare-burning effect.

Fire: Water spray, foam, dry chemical. Some may be extinguished with CO2.

Spill: Eliminate ignition sources. Do not touch. Cover with dry earth, sand, or non-combustible material.

Chemical and Physical Properties

Nitronaphthalene appears as a yellow crystalline solid. Insoluble in water and denser than water. May irritate skin and eyes. Readily ignitable and may be difficult to extinguish once ignited. Used to make dyes and other chemicals.

CAS Number: 91-64-5
Molecular Formula: C10H7NO2
Molecular Weight: 173.17 g/mol
Color / Form: Pale yellow needles
Odor: Odorless
Boiling Point: 579 F
Melting Point: 142.7 °F (NTP, 1992)
Flash Point: 327 F
Specific Gravity: 1.332 (sinks in water)
Vapor Pressure: 0.00048 [mmHg]
Vapor Density: 5.96 (heavier than air)
Water Solubility: less than 0.1 mg/mL at 72 F
Log P: log Kow= 3.19

Special Provisions

49 CFR 172.102 special provision codes for this entry: A1, IB8, IP3, T1, 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.

Need the full interactive record? Open UN 2538 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.