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Chemical Name: 3,3'-Dichlorobenzidine
Common Names: o,o'-Dichlorobenzidine
Chemical Formula: C12H10Cl2N2
CAS Number: 91-94-1
Physical Appearance: Pale yellow to grey crystalline solid
Odor: Odorless or faint aromatic smell
Solubility: Slightly soluble in water; more soluble in organic solvents
Uses: Precursor in dyes, pigments, and some polymers
Source: Synthetic, not found in nature; arises from industrial processes
Carcinogenicity: Recognized as carcinogenic to humans by agencies such as IARC and NTP
Acute Health Effects: Can cause irritation of the eyes, skin, and respiratory tract. Dust or vapor may be harmful if inhaled
Chronic Effects: Long-term exposure links to bladder cancer, and repeated contact can damage skin or internal organs
Routes of Exposure: Inhalation, skin absorption, ingestion
Target Organs: Bladder, liver, skin, kidneys
GHS Classification: Health hazard (carcinogen, mutagen), Environmental hazard (aquatic chronic), Skin sensitizer
3,3'-Dichlorobenzidine: 98% or higher by weight in technical grade material
Impurities: Minor traces of related chlorinated amines or aromatic amines can appear in industrial samples
Mixtures: Occasionally formulated with stabilizers or other aromatic amines in pigment production
Inhalation: Remove to fresh air, seek medical attention if symptoms persist
Skin Contact: Wash with soap and water for at least 15 minutes; remove contaminated clothing
Eye Contact: Rinse cautiously with water for several minutes, seek immediate medical care
Ingestion: Rinse mouth, do not induce vomiting, call poison control or a doctor
Special Advice: Medical personnel need to know chemical exposure history due to cancer risks
Symptom Monitoring: Look for rashes, cough, dizziness, or urinary issues
Suitable Extinguishing Media: Dry chemical powder, carbon dioxide, or foam
Hazardous Decomposition: Releases toxic fumes of nitrogen oxides, hydrogen chloride, and possibly phosgene upon burning
Special PPE: Firefighters need self-contained breathing apparatus and full protective gear
Unusual Hazards: Dust may form explosive mixtures with air during handling or processing
Fire Spread Control: Dike runoff water to prevent entry into drains or water sources
Thermal Stability: Not highly flammable, but heat and open flames can cause hazardous breakdown
Containment: Avoid dust formation; use local exhaust or containment enclosures
Clean-Up Methods: Pick up mechanically; use wet sweeping or industrial vacuum with HEPA filter for fine dust
Personal Precautions: Wear chemical-resistant gloves, goggles, and respiratory protection
Environmental Precautions: Prevent entry into sewers, waterways, or soil; notify authorities if large release occurs
Decontamination: Wash area with soap and water, collect residues for hazardous disposal
Disposal of Materials: Place in labeled hazardous waste containers for regulated removal
Storage Requirements: Store in tightly closed containers in a cool, ventilated space away from direct sunlight or heat sources
Segregation: Keep clear of acids, oxidizers, and food items
Labeling: Containers need clear hazard labels and restricted access
Handling Tips: Use with local exhaust ventilation, keep handling times short, minimize airborne dust
Spill Planning: Facilities handling large volumes benefit from spill containment plans and regular training
Transfer Precautions: Use dedicated tools to avoid cross-contamination
Engineering Controls: Fume hoods, local exhaust systems, enclosed processes
Workplace Limits: OSHA and ACGIH set limits for occupational exposure as low as feasible due to cancer risk (typically <0.1 mg/m³)
Protective Equipment: NIOSH-approved respirators, nitrile gloves, chemical goggles, protective clothing
Monitoring: Regular air sampling, surface wipe testing, and medical surveillance of exposed workers
Hygiene Measures: Prohibit eating, drinking, or smoking in work areas; wash thoroughly after handling
Appearance: Pale yellow or grayish crystals
Odor: Odorless or barely aromatic
Melting Point: 132–133°C
Boiling Point: Data limited due to decomposition
Solubility: Slightly soluble in water, more in ethanol, benzene, or ether
Density: Approx. 1.42 g/cm³
Vapor Pressure: Negligible at room temperature
Molecular Weight: 253.13 g/mol
Other Properties: Not volatile, forms dust easily if handled roughly
Chemical Stability: Stable under recommended storage conditions
Conditions to Avoid: Strong oxidizers, acids, direct heat, open flames
Hazardous Reactions: May react violently with oxidizers; not expected to polymerize
Decomposition Products: Toxic fumes such as hydrogen chloride and nitrogen oxides
Incompatibility: Strong acids, bases, and oxidizing agents
Routes of Exposure: Skin absorption, inhalation, accidental ingestion
Acute Toxicity: May cause eye, skin, and respiratory irritation. Data suggests single large doses have led to drowsiness, nausea, and pain
Chronic Toxicity: Evidence of human carcinogenicity, especially in bladder tissue—based on occupational studies and animal testing
Sensitization: Skin and respiratory system sensitizer in workers
Organ-specific Effects: Bladder is the principal cancer target; other impacts reported in liver and kidneys
Mutagenicity: Studies link to DNA damage and genetic mutations in lab settings
Reproductive Toxicity: Insufficient human data, animal studies ongoing
Symptoms of Exposure: Chronic cough, skin rashes, blood in urine, digestive discomfort
Persistence: Degrades slowly in soil and surface water, can persist for months or longer
Bioaccumulation: Moderate potential due to lipophilicity
Aquatic Toxicity: Harmful to aquatic life; fish and invertebrates show effects at low concentrations
Environmental Fate: Attaches to sediments, may migrate in groundwater; photodegrades slowly
Ecosystem Effects: Long-term threat if dumped untreated; impacts are magnified in sewage and river outflows in dye-manufacturing regions
Hazardous Waste Classification: Regulated as hazardous due to carcinogenicity and toxic effects
Disposal Method: Incinerate in approved chemical incinerators capable of scrubbing acid gases
Packaging: Seal in compatible containers clearly marked for hazardous waste
Prohibitions: Avoid landfilling untreated material; don’t rinse into water systems
Remediation: Large spills need professional hazardous waste handlers and decontamination protocols
Shipping Name: “Toxic solid, organic, n.o.s. (contains 3,3'-dichlorobenzidine)” under international transport regulations
UN Number: UN2811
Class: 6.1 (Toxic substances)
Packing Group: II or III depending on purity and amount
Transport Regulation: Subject to DOT, IMDG, IATA controls for industrial chemicals; emergency response guides require immediate isolation if packaging breaks
Special Handling: Containers need secondary containment, hazard signage, and documentation
Occupational Limits: Exposure limits updated by OSHA, ACGIH, and NIOSH due to strong evidence of cancer risk
Environmental Laws: Listed as hazardous under CERCLA and RCRA in the United States
Control Status: Use tightly restricted in many countries, especially in dye manufacturing; subject to REACH registration in Europe
Reporting Requirements: Mandatory incident and release reporting; periodic inventory reporting for regulated industries
Cancer Warnings: California Prop 65 includes this compound among known human carcinogens
Worker Training: Required under OSHA’s Hazard Communication Standard before handling
Label Requirements: GHS pictograms for acute toxicity, carcinogenicity, and environmental toxicity
