Common Name: Urea
Chemical Formula: CH4N2O
CAS Number: 57-13-6
Appearance: White, odorless solid, mostly in prilled or granulated form
Synonyms: Carbamide, carbonyldiamide
Use: Primarily fertilizer, but used in adhesives, animal feed, and industrial resins
Health Hazards: Low toxicity for humans, though direct exposure can irritate eyes, skin, or respiratory system
Environment: Large spills in water can promote eutrophication, stressing aquatic life
Combustibility: Urea itself does not ignite easily, but decomposes at high temperatures to release ammonia and cyanic fumes
May aggravate pre-existing respiratory or dermatological conditions if exposed in dusty environments
Component: Pure urea with typical purity above 99%
Impurities: Trace amounts of biuret, formaldehyde, moisture, and ammonia—levels controlled as per local agricultural, food, or industrial code
No significant hazardous diluents present in fertilizer-grade products
Inhalation: Remove to fresh air; persistent symptoms call for medical attention
Skin Contact: Wash off with plenty of water; prolonged or repeated exposure may dry the skin
Eye Contact: Flush immediately with running water for several minutes; seek medical attention if irritation persists
Ingestion: Rinse mouth, give water if conscious; very large amounts warrant medical assessment for dehydration or gastrointestinal upset
Attention to eye and airway contact due to increased risk in industrial handling, especially powdered or dusty urea
Extinguishing Media: Use water spray, dry chemical, foam, or carbon dioxide for surrounding fires
Hazards from Combustion: Decomposes at above 133°C, producing ammonia, cyanuric acid, and potentially hazardous nitrogen oxides
Personal Protection: Firefighters should don self-contained breathing apparatus; vigorous combustion generates toxic off-gases
Prevent runoff from entering waterways, as it may support algal blooms
Spill Response: Sweep or shovel spilled urea into labeled containers; avoid water if risk of solution runoff
Personal Safety: Use dust masks or respirators if airborne concentration is high; gloves and goggles prevent irritation
Environmental Precaution: Prevent entry into drains or natural waters; spilled solids should be recovered, not washed away
Clean-Up: Vacuum or low-dust sweeping reduces airborne particles; avoid unnecessary water use that could push urea into soil or drains
Handling: Use appropriate dust extraction and avoid open bags or tipping; minimize skin, eye, and respiratory exposure
Storage: Store in cool, dry, well-ventilated areas; separate from incompatible chemicals like strong acids and oxidizers
Bulk Management: Moisture in storage increases risk of caking, which can disrupt dosing or create compaction in silos
Containers: Use corrosion-resistant bins, keep packaging sealed until use, and stack conforming to safety recommendations
Engineering Controls: Local ventilation or extraction systems in transfer and handling areas
Personal Protective Equipment: Work gloves, chemical splash goggles, coveralls in high-dust settings; N95-rated respirators for persistent airborne particles
Exposure Limits: No strict legal limits in most jurisdictions, though operators keep workplace concentrations as low as practical, with monitoring for ammonia should heating or decomposition occur
Hygiene: Wash hands after handling, restrict eating or drinking near active loading or transfer points
Physical State: Solid; traded as prills or granules
Melting Point: 132.7°C
Boiling Point: Decomposes before boiling
Solubility in Water: Highly soluble
Odor: Odorless in solid state, faint ammonia on slow hydrolysis
Density: About 1.32 g/cm3
pH: Slightly acidic solution in pure water
Stability: Stable under ambient conditions but hygroscopic if exposed to moisture
Chemical Stability: Does not show dangerous reactivity under normal temperatures and pressures
Incompatible Materials: Strong acids, strong bases, hypochlorites, and nitrates can react dangerously
Hazardous Decomposition: Decomposes above melting point to ammonia, biuret, and potentially harmful nitrogen-containing gases
Conditions to Avoid: High humidity, open flames, and prolonged contact with incompatible chemicals
Acute Toxicity: Low by all routes of exposure as demonstrated by animal and worker studies; LD50 (oral, rat) above 8,000 mg/kg
Irritation: Dust or direct contact can cause mild irritation of eyes, skin, and respiratory system
Chronic Exposure: No evidence of carcinogenicity or reproductive toxicity in humans
Occupational Data: Decades of fertilizer production show little long-term health impact provided dust control and basic PPE are used
Aquatic Effects: High urea concentrations lead to algal blooms, followed by reduced oxygen in water bodies
Persistence: Breaks down quickly in soil to ammonia and then nitrate, so not persistent as urea but can contribute to nutrient overloading
Bioaccumulation: Does not persist in tissues, quickly metabolized by organisms
Spills: Localized over-fertilization in soils or waterways can harm plant and microbial balance
Unused Product: Apply to fields at agronomically appropriate rates; sending non-contaminated urea to landfill wastes resource and may leach
Contaminated Urea: If mixed with hazardous substances, handle as per those substances and local environmental code
Packaging: Triple-rinse and recycle or dispose according to plastics and hazardous materials rules
Spill Residue: If not reusable, treat in accordance with local regulatory protocols for non-hazardous but nutrient-dense wastes
Regulation: Not regulated as a hazardous material for land, sea, or air transport
Precaution: Keep loads dry and prevent mechanical loss during transport; avoid mixing loads with oxidizers, acids
Packaging: Use strong, moisture-resistant bags, bulk tankers lined to prevent corrosion
Spill Response En Route: Recover and containerize spilled material, notify concerned environmental authorities if waterway contamination occurs
Labor Standards: Subject to general occupational safety codes covering chemical handling
Environment: Water quality laws restrict large or accidental discharges to aquatic ecosystems by controlling runoff, leaching, and storage
Global Trade: Controlled by customs codes in some countries due to potential for misuse in illicit chemical production
Labeling: Transport and warehouse labeling required for accurate identification and emergency response according to international GHS guidelines
