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SULFUR TRIOXIDE
ICSC: 1202
Peer-Review Status: 10.10.2002 Validated
Sulphuric (acid) anhydride
Sulfuric oxide 
CAS #: 7446-11-9 RTECS #: WT4830000
UN #: 1829
EINECS #: 231-197-3
    Formula: SO3
Molecular mass: 80.1

TYPES OF
HAZARD /
EXPOSURE
ACUTE HAZARDS / SYMPTOMS      PREVENTION      FIRST AID / FIRE FIGHTING
FIRE Not combustible. Heating will cause rise in pressure with risk of bursting. Gives off irritating or toxic fumes (or gases) in a fire.  NO contact with bases, combustible substances, reducing agents or water.  NO hydrous agents. NO water. In case of fire in the surroundings, use appropriate extinguishing media. 
EXPLOSION Risk of fire and explosion on contact with bases, combustible substances, reducing agents or water.    In case of fire: keep drums, etc., cool by spraying with water. NO direct contact with water. 
 
EXPOSURE   PREVENT GENERATION OF MISTS! AVOID ALL CONTACT!  IN ALL CASES CONSULT A DOCTOR! 
Inhalation Burning sensation. Cough. Laboured breathing. Sore throat. Wheezing. Shortness of breath.  Use ventilation, local exhaust or breathing protection.  Fresh air, rest. Half-upright position. Refer for medical attention. 
Skin Redness. Serious skin burns. Pain. Blisters.  Protective gloves. Protective clothing.  Remove contaminated clothes. Rinse skin with plenty of water or shower. Refer for medical attention . 
Eyes Redness. Pain. Blurred vision. Severe deep burns.  Wear face shield or eye protection in combination with breathing protection.  First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention. 
Ingestion Abdominal pain. Burning sensation. Nausea. Shock or collapse.  Do not eat, drink, or smoke during work.  Refer for medical attention . Rinse mouth. Do NOT induce vomiting. Give one or two glasses of water to drink. 

SPILLAGE DISPOSAL
PACKAGING & LABELLING
Evacuate danger area! Consult an expert! Personal protection: chemical protection suit including self-contained breathing apparatus. Ventilation. NEVER direct water jet on liquid. Do NOT let this chemical enter the environment. Do NOT absorb in saw-dust or other combustible absorbents. Absorb remaining liquid in dry sand or inert absorbent. Then store and dispose of according to local regulations.  Do not transport with food and feedstuffs.
Airtight. 
EC Classification
 
UN Classification
UN Hazard Class: 8; UN Pack Group: I 
GHS Classification
 

EMERGENCY RESPONSE SAFE STORAGE
Transport Emergency Card: TEC (R)-80GC1-I-X.
NFPA Code: H3; F0; R2. 
Store only if stabilized. Separated from food and feedstuffs and incompatible materials. See Chemical Dangers. Dry. Store between 17°C and 25°C. 

IMPORTANT DATA
Physical State; Appearance
FUMING HYGROSCOPIC COLOURLESS LIQUID OR COLOURLESS-TO-WHITE CRYSTALS. 

Physical dangers
The vapour is heavier than air. See Notes. 

Chemical dangers
The substance is a strong oxidant. It reacts violently with combustible and reducing materials and organic compounds. This generates fire and explosion hazard. Reacts violently with water and moist air. This produces sulfuric acid. The solution in water is a strong acid. It reacts violently with bases and is corrosive to metals. This produces flammable/explosive gas (hydrogen - see ICSC 0001). 

Occupational exposure limits
TLV (NOT-ESTABLISHED):. 

Routes of exposure
The substance can be absorbed into the body by inhalation of its vapour and by ingestion. 

Inhalation risk
A harmful contamination of the air will be reached very quickly on evaporation of this substance at 20°C. 

Effects of short-term exposure
The substance is corrosive to the eyes, skin and respiratory tract. Corrosive on ingestion. 

Effects of long-term or repeated exposure
Repeated or prolonged inhalation of the aerosol may cause effects on the lungs. Repeated or prolonged inhalation of the aerosol may cause effects on the teeth. This may result in tooth erosion. Strong inorganic acid mists containing this substance are carcinogenic to humans. 


PHYSICAL PROPERTIES ENVIRONMENTAL DATA
Boiling point: 45°C
Melting point: see Notes
Relative density (water = 1): 1.9
Solubility in water: reaction
Vapour pressure: see Notes
Relative vapour density (air = 1): 2.8
Relative density of the vapour/air-mixture at 20°C (air = 1): 1.2-2 
The substance is harmful to aquatic organisms. 

NOTES
NEVER pour water into this substance; when dissolving or diluting always add it slowly to the water.
When the alpha form melts it takes the gamma form, and vapor pressure rises dramatically with a hazard of explosion.
Melting point is 62, 33 and 17°C for alpha, beta and gamma forms.
Vapour pressure is 9.7, 45.9 and 57.7 kPa at 25°C for alpha, beta and gamma forms. 

ADDITIONAL INFORMATION
 

IPCS
International
Programme on
Chemical Safety
WHO ILO EC Prepared in the context of cooperation between the International Programme on Chemical Safety and the European Commission
© IPCS 2004-2012
LEGAL NOTICE Neither the EC nor the IPCS nor any person acting on behalf of the EC or the IPCS is responsible for the use which might be made of this information.


    See Also:
       Toxicological Abbreviations