© 2026 Nanjing Finechem Holdings Co., Ltd,
All Right Reserved
Product Name: Methanesulfonic Acid
Chemical Family: Alkane sulfonic acids
Chemical Formula: CH4O3S
Synonyms: MSA, methylsulfonic acid, methane sulphonic acid
CAS Number: 75-75-2
Intended Use: Electroplating, organic synthesis, pharmaceuticals, cleaning agent
Supplier: Name and address of manufacturer or distributor
Emergency Contact: Local poison control center, supplier emergency hotline
Prepared by: Health and Safety Officer
Date of Preparation: Most recent revision date
Classification: Corrosive to metals, causes severe skin burns and eye damage, causes serious eye damage
Label Elements: Danger, corrosive pictograms, hazard and precautionary statements
Hazard Statements: May be fatal if swallowed, causes burns to mouth and throat, immediately harmful on skin contact due to deep tissue irritation, causes permanent eye damage
Signal Word: Danger
Precautionary Statement: Wear eye and face protection, wear protective gloves and clothing, avoid breathing vapors, use only outdoors or in well-ventilated areas, wash exposed skin thoroughly after handling
Routes of Exposure: Inhalation, ingestion, skin contact, eye contact
Chronic Effects: Repeated exposure may damage respiratory system and digestive system, potential to cause chronic dermatitis
Target Organs: Eyes, skin, respiratory tract, digestive tract
Chemical Identity: Methanesulfonic Acid
Concentration: Typically 70% purity, can range from 60-99% depending on source
CAS Number: 75-75-2
EC Number: 200-898-6
Impurities: Water, trace organic sulfonates, trace metals depending on manufacturer
Additives: None stated
General Advice: Remove victim from exposure source, call emergency services immediately, avoid direct contact when helping victims
Inhalation: Move affected person to fresh air, seek medical attention, keep victim warm and at rest, provide oxygen if breathing becomes difficult
Skin Contact: Remove contaminated clothing immediately and wash skin with plenty of running water for at least fifteen minutes, do not use neutralizing chemicals on the skin without advice from a physician, seek immediate medical attention even if symptoms seem minor
Eye Contact: Rinse eyes thoroughly with water for at least fifteen minutes, lift upper and lower eyelids occasionally, remove contact lenses, seek immediate medical attention
Ingestion: Rinse mouth with water, do not induce vomiting, seek immediate medical attention, never give anything by mouth to an unconscious person
Suitable Extinguishing Media: Use water fog, carbon dioxide, chemical powder, or foam
Unsuitable Extinguishing Media: Do not use water jets that might spread acid
Hazardous Combustion Products: Sulfur oxides, toxic thermally-degraded products, acidic vapors
Special Hazards Arising from Substance: Reacts with most metals to form hydrogen gas which is flammable/explosive, emits irritating and toxic fumes when heated
Protective Equipment and Precautions for Firefighters: Use fully encapsulated chemically resistant suits, self-contained breathing apparatus, isolate area and keep upwind, do not allow contaminated runoff into sewers or waterways
Personal Precautions: Evacuate unnecessary personnel, ventilate area, use personal protective equipment including acid-resistant gloves and eyewear
Environmental Precautions: Prevent spillage from entering drains, soil, or water sources, inform relevant authorities if large quantities enter environment
Methods for Containment: Contain spills using inert, non-combustible materials such as sand or earth, avoid contact with incompatible materials
Clean Up Procedures: Absorb with inert material and collect in acid-resistant containers for disposal, wash spill area with plenty of water after absorption, avoid direct handling, ventilate area thoroughly after cleanup
Decontamination: Rinse tools and equipment with water, do not use alkaline neutralizers without consulting manufacturer or safety specialist
Safe Handling: Use only in well-ventilated areas, keep containers tightly closed, do not breathe vapors or allow contact with skin or eyes, avoid generating aerosols or sprays, transfer using corrosion-resistant equipment, never mix with bases or oxidizers
Storage Requirements: Store in original acid-resistant containers, keep away from incompatible substances including oxidizers and alkalis, store between 5–30°C out of direct sunlight, keep away from ignition sources, store in cool, dry, well-ventilated areas, keep storage area clearly labeled and secure
Incompatible Materials: Metals, strong bases, strong oxidizers, some organic materials
Special Handling Advice: Label all containers clearly, ensure spill kits and emergency wash stations are accessible, monitor storage area for corrosion or leaks
Exposure Limits: No established OSHA or ACGIH limits, recommend minimizing exposure as much as possible, consider internal guidelines (company-based OELs)
Engineering Controls: Use process enclosures, local exhaust ventilation, or other engineering controls to keep airborne levels below recommended exposure limits, use corrosion resistant ventilation systems
Personal Protective Equipment: Acid-resistant gloves (butyl rubber, neoprene), splash goggles and face shield, chemical-resistant apron and boots, full impervious suit for high-risk conditions
Respiratory Protection: In case of insufficient ventilation, use approved respiratory protection appropriate for acid vapors (NIOSH/MSHA approved), ensure emergency respiratory equipment is available
Hygiene Measures: Wash hands, forearms, and face after handling, remove contaminated clothing and wash before reuse, avoid eating, drinking, or smoking in work areas, provide dedicated washing facilities at worksite
Appearance: Colorless to pale yellow liquid, may be slightly viscous
Odor: Slightly pungent, sour
Odor Threshold: Not available
pH: Strongly acidic in solution
Melting Point: Approximately -54°C
Boiling Point: Approximately 167°C at 760 mmHg
Flash Point: Not flammable under typical conditions
Evaporation Rate: Slower than water
Flammability: Does not burn in normal conditions
Explosive Properties: None
Vapor Pressure: 0.6 mmHg at 20°C
Vapor Density: Heavier than air
Relative Density: 1.48 g/cm3 at 20°C
Solubility: Miscible in water, soluble in alcohols and some organic solvents
Partition Coefficient (log Kow): -2.2
Auto-ignition Temperature: Not applicable
Decomposition Temperature: No reliable data available
Viscosity: Approximately 11.6 mPa·s at 25°C
Chemical Stability: Stable under standard storage conditions, can absorb moisture from the air, can react with water producing heat
Reactivity: Reacts vigorously with bases, can react dangerously with some metal powders, especially aluminum, zinc, and their alloys
Possibility of Hazardous Reactions: Gives off heat when mixed with water, hydrogen gas evolves with contact with metals, combustible gas formation
Incompatible Materials: Alkalis, oxidizing agents, reactive metals (aluminum, zinc, magnesium), cyanides, strong reducing agents
Hazardous Decomposition Products: Sulfur dioxide, sulfur trioxide, carbon monoxide, carbon dioxide
Polymerization: Will not occur spontaneously or under normal handling procedures
Acute Toxicity: Oral LD50 (rat): 2,090 mg/kg, data may vary; causes deep burns to mucous membranes and digestive tract on ingestion
Skin Corrosion/Irritation: Causes severe burns, irreversible tissue damage, risk of scarring
Eye Damage/Irritation: Causes rapid, severe destruction of eye tissue, potential for blindness
Respiratory Effects: Inhalation of vapors may cause coughing, sore throat, and difficulty breathing, effects can be serious especially in enclosed spaces
Chronic Effects: Prolonged skin contact may result in dermatitis, long-term inhalation may cause irreversible respiratory irritation or damage
Carcinogenicity: No known carcinogenicity per IARC, NTP, OSHA
Mutagenicity: No evidence identified
Reproductive Toxicity: No specific risks identified
Sensitization: Not classified as a sensitizer
Aquatic Toxicity: Harmful to aquatic organisms if released in significant amounts, due to strong acidity
Persistence and Degradability: Readily biodegradable in water, acidifies water bodies immediately
Bioaccumulation Potential: Low, methanesulfonic acid has weak potential to bioaccumulate due to high solubility
Soil Mobility: Highly mobile in soil, leaches into groundwater rapidly
Ecosystem Impact: Acidification of water sources and soil, lowers pH making environment toxic for aquatic life
Other Environmental Hazards: Avoid uncontrolled raw discharge to environment, report spills as required by regulations
Waste Treatment Methods: Disposal must comply with local, regional, and national regulations, consult with environmental authorities prior to disposal
Product Disposal: Do not discharge to surface waters or drains, neutralize with sodium bicarbonate or similar substances under controlled, ventilated conditions before disposal, collect neutralized solution for transport by approved hazardous waste contractors
Contaminated Packaging: Rinse thoroughly with water before recycling or disposal, treat rinsate as hazardous waste, dispose of containers in line with local hazardous waste guidelines
Special Precautions: Never reuse empty acid containers for food or drink, store waste in corrosion-resistant, clearly identified containers until collection
UN Number: UN 3265
Proper Shipping Name: Corrosive liquid, acidic, organic, n.o.s. (Methanesulfonic Acid)
Transport Hazard Class: 8 (Corrosive substances)
Packing Group: II
Marine Pollutant: Not listed as a marine pollutant, but spill response and prevention remains critical
Labels: Corrosive (Class 8)
Special Transport Precautions: Ensure containers are upright, tightly sealed, and secure during transport, segregate from incompatible cargo such as alkalis and oxidizers, emergency procedures for spill response must be included in transport paperwork, persons involved must be trained in transport accident response
International Regulations: Listed in EINECS, TSCA, REACH, and other national chemical inventories, identified as hazardous under GHS (Globally Harmonized System)
US Federal Regulations: OSHA hazardous chemical by definition, not a CERCLA or RCRA hazardous waste, check SARA Title III reporting requirements
State Regulations: Subject to specific labeling and reporting laws in US states that regulate highly corrosive chemicals
EU Regulations: Controlled under REACH, subject to restrictions on handling and labeling, must follow safety data sheet distribution requirements
Labelling Requirements: Hazard pictograms, risk and safety phrases, emergency contact information must be clearly displayed on all packaging and storage units
Workplace Requirements: Compliance with workplace safety and health regulations including staff training, access to Material Safety Data Sheets, ready availability of emergency wash stations
