Material Safety Data Sheet (MSDS) for 1,3-Dichloro-5,5-dimethylhydantoin (DCDMH)

Identification

Product Name: 1,3-Dichloro-5,5-dimethylhydantoin
Synonyms: DCDMH, 1,3-Dichloro-5,5-dimethylimidazolidine-2,4-dione
CAS Number: 118-52-5
Molecular Formula: C5H6Cl2N2O2
Molecular Weight: 197.02 g/mol
Recommended Use: Disinfection, water treatment, sanitization
Supplier: Information can be obtained from chemical provider or workplace safety officer
Emergency Contact: Local poison control center or emergency services
Contact Details: Manufacturer’s phone number should appear on purchase invoice

Hazard Identification

GHS Classification: Oxidizing Solid (Category 2), Acute Toxicity Oral (Category 4), Eye Irritation (Category 2A), Skin Irritation (Category 2), Environmental Hazard Aquatic Chronic (Category 1)
Signal Word: Danger
Hazard Statements: May intensify fire (oxidizer). Harmful if swallowed. Causes skin irritation. Causes serious eye irritation. Very toxic to aquatic life with long lasting effects.
Pictograms: Flame over circle, exclamation mark, environment
Precautionary Statements: Keep away from heat and ignition sources. Wear protective gloves, protective clothing, eye and face protection. Avoid release to the environment. Wash hands thoroughly after handling. Do not eat, drink, or smoke while using this product.
Other Hazards: Reacts violently with reducing agents, acids, and organic materials. Releases toxic gases when wet or heated.

Composition / Information on Ingredients

Chemical Name: 1,3-Dichloro-5,5-dimethylhydantoin
Concentration: 99-100% (technical grade)
CAS Number: 118-52-5
Impurities: Trace amounts of organic or inorganic contaminants based on production batch

First Aid Measures

Inhalation: Move person to fresh air. Keep at rest. If symptoms persist, get medical attention.
Skin Contact: Remove contaminated clothing. Rinse exposed skin thoroughly with water for at least 15 minutes. Seek medical advice if irritation develops.
Eye Contact: Rinse with plenty of water for at least 15 minutes, holding eyelids apart. Remove contact lenses if present and easy to do. Call for medical help immediately.
Ingestion: Rinse mouth. Do not induce vomiting. Get medical attention promptly.
Most Important Symptoms/Effects: Irritation of skin, eyes, and mucous membranes, difficulty breathing, gastrointestinal distress.
Notes for Doctor: Treat based on symptoms. Exposed persons may develop delayed symptoms after exposure.

Fire-Fighting Measures

Suitable Extinguishing Media: Use water spray, fog, or foam. Do not use dry chemicals or carbon dioxide as the chemical reacts with these agents.
Specific Hazards: Material is a strong oxidizer. Promotes combustion of other substances. Decomposes at high temperatures, releasing toxic and corrosive gases including chlorine, nitrogen oxides.
Special Protective Equipment: Firefighters need self-contained breathing apparatus and chemically resistant clothing.
Fire-Fighting Instructions: Isolate upwind. Remove containers from hazard area if safe to do so. Cool containers exposed to fire with water spray.

Accidental Release Measures

Personal Precautions: Evacuate area. Avoid breathing dust or vapor. Wear proper protective clothing including gloves, goggles, and dust mask or respirator.
Environmental Precautions: Prevent spill from entering drains, surface waters, and soil.
Methods for Cleanup: Scoop up and place in a clean, dry, tightly sealed container for disposal according to local regulations. Avoid generating dust. Ventilate area.
Decontamination: Wash spill area with large amounts of water. Do not use combustible materials for cleaning.

Handling and Storage

Handling: Use only in well-ventilated areas. Do not get on skin or in eyes. Minimize dust generation and accumulation. Use non-sparking tools.
Storage: Store in a cool, dry, well-ventilated place away from heat, moisture, strong acids, bases, and compatible organic materials. Keep container tightly closed, properly labeled, and away from direct sunlight.
Incompatibilities: Acids, ammonia, ammonium salts, strong reducing agents, combustible materials, organic chemicals.
Conditions to Avoid: Exposure to moisture, heat, and incompatible substances.

Exposure Controls and Personal Protection

Occupational Exposure Limits: No established OSHA or ACGIH limits for this substance
Engineering Controls: Use general or local exhaust ventilation to keep airborne levels below recommended exposure limits.
Personal Protective Equipment: Chemical-resistant gloves (such as nitrile or neoprene), safety goggles or face shield, protective clothing (lab coat or apron). In case of inadequate ventilation, use NIOSH-approved respiratory protection.
Hygiene Measures: Wash hands and face after handling. Remove contaminated clothing and wash before reuse.

Physical and Chemical Properties

Appearance: White crystalline powder
Odor: Slight chlorine or bleach-like scent
Melting Point: Approximately 132°C
Boiling Point: Decomposes above 160°C
Solubility: Slightly soluble in water; more soluble in organic solvents
Density: About 1.5 g/cm³
pH (1% solution): 5.0 – 6.0
Vapor Pressure: Not significant at room temperature
Partition Coefficient: No data available
Flash Point: Not flammable as a solid
Oxidizing Properties: Strong oxidizer, supports combustion
Stability in Storage: Gradually decomposes in moist air

Stability and Reactivity

Chemical Stability: Stable under dry, normal temperature and pressure conditions.
Possibility of Hazardous Reactions: Reacts violently with acids, reducing agents, ammonia, and organic materials. May decompose with moisture and release toxic gases.
Incompatible Materials: Acids, alkalis, ammonium salts, reducing agents, organic materials, combustible substances.
Hazardous Decomposition Products: Chlorine, nitrogen oxides, carbon monoxide, carbon dioxide.
Conditions to Avoid: Heat, flames, moisture, and incompatible substances.

Toxicological Information

Acute Toxicity: Harmful if swallowed (LD₅₀ oral rats: ~770 mg/kg). May be harmful in contact with skin or if inhaled in large quantities.
Skin Corrosion/Irritation: Causes moderate irritation on contact.
Eye Damage/Irritation: Causes severe eye irritation and possible irreversible damage without prompt rinsing.
Respiratory Sensitization: May irritate respiratory tract.
Long-Term Exposure Risks: No conclusive evidence on carcinogenic, mutagenic, or reproductive toxicity. Prolonged exposure has potential to aggravate asthma, dermatitis, or existing medical conditions.
Symptoms of Overexposure: Eye redness, skin rash, headache, cough, gastrointestinal upset.

Ecological Information

Aquatic Toxicity: Very toxic to fish and aquatic invertebrates at low concentrations.
Persistence and Degradability: Hydrolyzes in water to form less hazardous compounds, but initial breakdown can release chlorine compounds harmful to aquatic systems.
Bioaccumulation Potential: Not expected to significantly bioaccumulate, but acute aquatic toxicity is significant.
Mobility in Soil: Product is mobile in water, especially if spilled into natural waterways, and can cause lasting impacts.
Other Adverse Effects: Releases active chlorine into the environment, disrupting biological oxygen demand and aquatic balance.

Disposal Considerations

Waste Treatment Methods: Dispose of contents in a permitted chemical waste facility. Local, regional, and national regulations for hazardous waste disposal must be followed. Do not dispose of via municipal or household drains.
Container Disposal: Empty container should be handled with care. Rinse thoroughly before discarding or recycling. Never reuse empty containers for food or drink.
Precautions: Neutralize waste solutions before disposal when possible; avoid contact with organic or readily combustible materials during handling and disposal.

Transport Information

UN Number: UN 3077
Proper Shipping Name: Environmentally Hazardous Substance, Solid, N.O.S. (Contains 1,3-Dichloro-5,5-dimethylhydantoin)
Hazard Class: 9 (Miscellaneous dangerous substances)
Packing Group: III
Label: Class 9, environmentally hazardous.
Special Precautions: Prevent package damage, segregate from food and animal feeds.
Transport Regulations: Subject to international and local transport regulations; check latest applicable guidelines for road, rail, air, and sea.

Regulatory Information

U.S. Regulations: Listed in TSCA inventory. SARA Title III Section 313: Not listed. OSHA Hazard Communication Standard: Classified as hazardous.
EU Regulations: Included under REACH; labeled as hazardous per EC 1272/2008. Not on list of substances of very high concern.
Other Regional Laws: Compliance with chemical control laws in countries where distributed is required. Subject to labeling and environmental release notification in several jurisdictions.
Label Requirements: GHS pictograms, hazard and precautionary statements.
Restrictions on Use: For industrial and professional use only. Not for personal or consumer use. Observe national pesticide and water treatment safety codes.