UN/NA Number Reference
DOT Class 6.1 Toxic Substance placard

UN 1651: Naphthylthiourea

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1651 is assigned the proper shipping name Naphthylthiourea 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 II. 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 153)

Hazards: TOXIC. Combustible. Corrosive. Causes burns. Toxic fumes when heated.

Fire: Small: dry chemical, CO2, water spray. Large: water spray, foam.

Spill: Do not touch. Stop leak if safe. Use water spray to reduce vapor.

Chemical and Physical Properties

Antu appears as white crystal or powder; technical product is gray powder. Has no odor but a bitter taste. Used primarily as a rodenticide for control of adult Norway rats. Not produced commercially in the U.S. (EPA, 1998)

CAS Number: 108-98-5
Molecular Formula: C11H10N2S
Molecular Weight: 202.28 g/mol
Color / Form: Prisms from alcohol
Odor: Odorless
Boiling Point: Decomposes
Melting Point: 388 °F (EPA, 1998)
Flash Point: May burn but will not ignite readily (EPA, 1998)
Specific Gravity: Specific Gravity (water= 1): Greater than 1
Vapor Pressure: 0 mmHg at 77 F
Vapor Density: 6.99 (heavier than air)
Water Solubility: 0.06 %
Log P: log Kow = 1.65
pH: Feebly acidic

Regulatory Data

CERCLA RQ (40 CFR 302.4)
100 lb
EPCRA TPQ (40 CFR 355)
500 lb
OSHA PEL
TWA 0.3 mg/m 3
NIOSH REL
TWA 0.3 mg/m 3
IDLH
100 mg/m 3
RCRA Waste Code(s)
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A release of this material at or above its CERCLA reportable quantity (100 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.

Need the full interactive record? Open UN 1651 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.