Material Safety Data Sheet – Methylselenocysteine

Identification

Chemical Name: Methylselenocysteine
Synonyms: Se-methyl-L-selenocysteine; Selenocysteine methyl ester
CAS Number: 26046-90-2
Recommended Use: Laboratory chemical, nutritional supplement research
Manufacturer: Details available on request, ensure to identify supplier for specific handling information
Emergency Contact: Local Poison Control Center, Supplier Emergency Number

Hazard Identification

Classification: Acute toxicity, oral (Category 3); Skin irritation (Category 2); Eye irritation (Category 2A)
Signal Word: Danger
Hazard Statements: Toxic if swallowed; causes skin irritation; causes serious eye irritation
Pictograms: Skull and crossbones, exclamation mark
Precautionary Statements: Avoid all unnecessary exposure. Wear protective clothing; Use gloves; Do not breathe dust or vapor; Wash thoroughly after handling; If swallowed, seek medical advice immediately

Composition / Information on Ingredients

Chemical Identity: Methylselenocysteine
Purity: ≥98% by weight
Major Components: Methylselenocysteine
Impurities: May contain trace selenium compounds, analyses from supplier recommended for specifics

First Aid Measures

Inhalation: Move to fresh air immediately. Assist breathing if necessary. Seek medical attention for any breathing difficulty.
Skin Contact: Remove contaminated clothing. Flush skin with plenty of water and soap for at least 15 minutes. Get medical attention if irritation occurs.
Eye Contact: Rinse cautiously with water for at least 15 minutes. Hold eyelids apart to ensure complete irrigation. Seek eye specialist attention if irritation persists.
Ingestion: Rinse mouth with water (do not induce vomiting). Seek immediate medical help. Show container or label if possible.
Other: Provide symptomatic therapy as required on medical direction.

Fire-Fighting Measures

Suitable Extinguishing Media: Use water spray, alcohol-resistant foam, dry chemical, or carbon dioxide. Do not apply direct water jet on burning product.
Specific Hazards: May produce toxic selenium and sulfur oxides on combustion. Evacuate downwind if fire occurs.
Protective Equipment: Firefighters should wear self-contained breathing apparatus, protective clothing, and avoid contact with skin and eyes.
Special Procedures: Avoid inhaling combustion gases. Cool spill area with water. Prevent run-off from entering water bodies or sewers.

Accidental Release Measures

Personal Precautions: Evacuate unnecessary personnel. Wear suitable protective clothing, gloves, and respiratory protection. Avoid dust generation.
Environmental Precautions: Prevent spill from entering water systems or sewers. Notify relevant authorities in case of large spill.
Spill Clean-Up Methods: Absorb spill with inert material such as sand or earth. Collect residue in closed, labeled containers. Ensure thorough area ventilation.
Disposal: Place collected material in appropriate government-approved waste containers.

Handling and Storage

Handling: Avoid breathing dust, vapors, or mist. Work in a fume hood or well-ventilated area. Do not get in eyes, on skin, or clothing. Minimizing personal exposure is essential for safe laboratory handling.
Storage: Store tightly closed in a cool, dry, and well-ventilated area, away from incompatible materials such as strong oxidizing agents or acids. Containers must remain clearly labeled.
Other Precautions: Keep away from direct sunlight, sources of ignition, and moisture. Access limited to trained personnel.

Exposure Controls and Personal Protection

Exposure Limits: No established occupational exposure limits for methylselenocysteine. Selenium compounds (as Se): OSHA PEL 0.2 mg/m³ (as selenium total dust).
Engineering Controls: Work in chemical fume hood. Use local exhaust or general room ventilation.
Personal Protection: Use approved respirators during potential exposure or spill cleanup. Wear goggles or face shield, chemical-resistant gloves, lab coat or apron. Wash hands before eating, drinking, or smoking.
Hygiene Measures: Keep work area clean and uncontaminated. Remove contaminated clothing immediately and wash before reuse.

Physical and Chemical Properties

Appearance: White to off-white crystalline powder
Odor: Odorless or faintly sulfurous
Molecular Formula: C4H9NO2Se
Molecular Weight: 196.08 g/mol
Melting Point: Decomposes above 200°C
Solubility: Soluble in water
pH: No data available for aqueous solutions
Boiling Point: Not available (decomposes)
Flash Point: Not applicable
Vapor Pressure: Not expected at room temperature
Dust Explosion Risk: Finely dispersed powders may present risk in confined environments—avoid buildup

Stability and Reactivity

Chemical Stability: Stable under normal lab conditions. Sensitive to moisture and light.
Hazardous Reactions: May react with oxidizers and strong acids, producing selenium oxides and other toxic compounds.
Decomposition Products: Selenium oxides, sulfur oxides, possibly methylselenol and other selenium-containing gases.
Conditions to Avoid: High temperatures, exposure to moisture, contact with acids or oxidizing agents.

Toxicological Information

Acute Toxicity: Oral toxicity data in rats reports LD50 values below 50 mg/kg. Exposure by inhalation or skin contact has not been reported in detail, but selenium compounds are toxic via almost all routes.
Symptoms: Skin and eye irritation, headaches, dizziness, gastrointestinal upset, garlic breath odor, metallic taste.
Chronic Effects: Selenium compounds, if ingested over longer periods or at higher doses, may cause selenosis, indicated by brittle hair/nails, skin lesions, and neurological symptoms.
Carcinogenicity: Not classified as carcinogenic by IARC, NTP, or OSHA. Chronic high-dose selenium exposures linked with other systemic health effects.
Other Data: Avoid ingestion, inhalation, or skin/eye contact. No known reproductive or developmental toxicity at low doses.

Ecological Information

Toxicity: Toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment. Selenium bioaccumulates in fish and can affect reproductive health.
Mobility: Soluble and mobile in water, may migrate in soil and surface water.
Persistence and Degradability: Not easily biodegradable; selenium can persist in water/sediment systems.
Bioaccumulation Potential: High, particularly in aquatic life.
Avoid Release: Prevent large or repeated releases to the environment; report significant environmental spills.

Disposal Considerations

Product Disposal: Treat as hazardous waste. Follow all local, state, and federal regulations for selenium-containing compounds.
Container Disposal: Empty containers may hold product residues. Do not reuse. Triple rinse, then dispose of according to regulations.
Recommended Methods: Incinerate in licensed chemical incinerator with afterburner and scrubber, or pass to licensed disposal contractor.
Avoid: Disposal to the environment, sewer, or regular landfill.

Transport Information

UN Number: Not assigned individually
Proper Shipping Name: Toxic solid, organic, n.o.s. (contains methylselenocysteine)
Transport Hazard Class: 6.1 (Toxic substances)
Packing Group: II or III based on packaging and concentration
Labelling: Toxic (skull and crossbones symbol)
Environmental Hazards: Dangerous for the environment—marine pollutant
Special Precautions: Adhere strictly to transport company’s documentation and marking requirements

Regulatory Information

OSHA Status: Classified as hazardous—handle following OSHA standards for laboratory chemicals and toxic substances.
TSCA Inventory: Not specifically listed—refer to selenium compounds for applicability.
SARA Title III: Not specifically listed, but selenium compounds may fall under community-right-to-know modules
European Union: Complies with REACH requirements for substance notification and safety (consult supplier SDS for updates).
Other Regulation: Check country-specific toxic chemical inventories, including Canada DSL, Australian AICS, and Japanese ENCS.
Labeling: Required GHS and national warnings for toxicity and environmental impact.
Worker Protection: Personal protective equipment must be provided by employer; training required for safe handling.