Richmond: Sulfur Trioxide Spill at General Chemical Corp.

Human Health Effects:

Human Toxicity Excerpts:

Irritant and corrosive to mucous membranes. May cause coughing, choking and severe discomfort in a concn of 1 ppm.
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

Sulfur trioxide causes pulmonary skin and eye damage since it forms sulfuric acid.
[Seiler, H.G., H. Sigel and A. Sigel (eds.). Handbook on the Toxicity of Inorganic Compounds. New York, NY: Marcel Dekker, Inc. 1988. 650]**PEER REVIEWED**

Contact with the liquid can be expected to cause devastating damage to the eye, as with concentrated sulfuric acid.
[Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986. 868]**PEER REVIEWED**

Even when particle size is very small (ie less than 1 um) so that particles are easily respirable, sulfuric acid is so irritating to the skin and mucous membranes that it is rare for this chemical to reach the finer bronchioles and alveoli. The defense mechanisms protecting the lung seem much less effective if the individual is unconscious. /Sulfuric acid/
[Nat'l Research Council Canada; Effects of Sulfur and its Inorganic Derivative in the Canadian Environment. p.290 (1977) NRCC No.15015]**PEER REVIEWED**

The effects of sulfur trioxide on man are similar to those of sulfur dioxide, although the irritant action is more powerful. ... As with sulfur dioxide, sulfur trioxide in air and in the moist nasal mucosa reacts with water to form a weak concentration of sulfuric acid. The effects of sulfur trioxide on health are essentially those of sulfuric acid.
[Aleksieva Z, Sulfur Compounds, OSHA Vol 2 (1972) as cited in Nat'l Research Council Canada; Effects of Sulfur and its Inorganic Derivatives in the Canadian Environment. p.289 (1977) NRCC No. 15015]**PEER REVIEWED**

A group of 20 workers exposed to sulfuric acid in the manufacture of storage batteries and a comparable control group from the same factory who were not exposed were studied. The concentrations of sulfuric acid, measured in the environment, were substanially higher than currently accepted standards; however, the size of the acid droplets and the proportion which would be sufficiently small to enter nasal passages were not given. The increased prevalence of /abnormal/ respiratory function tests were not statistically significant. The prevalence of discolored or eroded teeth was significantly higher in the exposed group, and varied directly with years of exposure. /Sulfuric acid/
[El-Sadik YM et al; J Occup Med 14: 224 (1972) as cited in Nat'l Research Council Canada; Effects of Sulfur and its Inorganic Derivatives in the Canadian Environment. p.289-90 (1977) NRCC No. 15015]**PEER REVIEWED**

Experimental evidence exists to suggest that a concentration of 5 mg/cu m can be tolerated for up to 5 minutes with no permanent damage; only observable response is a rapid increase in respiratory rate.
[Morando A; Medicina del Lavoro 47: 557 (1956) as cited in Nat'l Research Council Canada; Effects of Sulfur and Its Inorganic Derivatives in the Canadian Environment. p.290 (2977) NRCC No.15015]**PEER REVIEWED**

Skin, Eye and Respiratory Irritations:

Irritant ... to mucous membranes.
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

Sulfur trioxide ... causes great irritation of the eyes and resp tract, even at concn as low as 1 ppm in air.
[Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986. 868]**PEER REVIEWED**

Emergency Medical Treatment:

Emergency Medical Treatment:

  o   This overview assumes that basic life support measures
      have been instituted.                           

  SUMMARY OF EXPOSURE
   0.2.1.1 ACUTE EXPOSURE
     o   The major toxic effects of sulfur trioxide mimic those
         of SULFURIC ACID.
      1.  It is IRRITATING or CORROSIVE to the eyes, skin, and
          mucous membranes.
      2.  CHEMICAL PNEUMONITIS or NONCARDIOGENIC PULMONARY EDEMA
          may occur following inhalation.
     o   FROSTBITE INJURY may occur with dermal exposure to
         liquified sulfur trioxide.
  VITAL SIGNS
   0.2.3.1 ACUTE EXPOSURE
     o   Hypotension and bradycardia may occur as premorbid
         events in serious overexposure.
  HEENT
   0.2.4.1 ACUTE EXPOSURE
     o   EYES - Sulfur trioxide fumes are very irritating to the
         eyes.  It may cause severe eye injury following direct
         contact.
     o   NASOPHARYNGEAL - Exposure is very irritating to the
         upper respiratory tract and may cause burns of the
         mucous membranes, glottis, and nasopharynx.  Edema may
         cause upper airway obstruction.
  CARDIOVASCULAR
   0.2.5.1 ACUTE EXPOSURE
     o   Hypotension, depressed cardiac output and bradycardia
         may occur.
  RESPIRATORY
   0.2.6.1 ACUTE EXPOSURE
     o   ACUTE EXPOSURE - Bronchospasm, wheezing, and
         noncardiogenic pulmonary edema may occur.  Pulmonary
         hemorrhages have been seen in fatally-exposed
         experimental animals.
     o   CHRONIC EXPOSURE - Chronic obstructive pulmonary
         disease may occur.  Chronic bronchitis with wheezing
         may be noted.  Individuals with pre-existing
         bronchitis, bronchial asthma, or emphysema may be at
         greater risk.
   0.2.6.2 CHRONIC EXPOSURE
     o   Chronic obstructive pulmonary disease may occur.
         Chronic bronchitis with wheezing may be noted.
         Individuals with pre-existing bronchitis, bronchial
         asthma, or emphysema may be at greater risk.
  GASTROINTESTINAL
   0.2.8.1 ACUTE EXPOSURE
     o   Esophageal or gastrointestinal tract irritation or
         burns may be predicted to occur; late stricture
         formation could develop.  Nausea, vomiting, abdominal
         pain, bleeding, or perforation could occur acutely.
  DERMATOLOGIC
   0.2.14.1 ACUTE EXPOSURE
     o   BURNS - Serious caustic burns may develop following
         direct skin contact.
     o   FROSTBITE INJURY - Direct skin contact with the
         liquified material may cause frostbite injury.
  REPRODUCTIVE HAZARDS
    o   At the time of this review, no data were available to
        assess the potential effects of exposure to this agent
        during pregnancy or lactation.
  CARCINOGENICITY
   0.2.21.2 HUMAN OVERVIEW
     o   At the time of this review, no data were available to
         assess the carcinogenic potential of this agent.
  GENOTOXICITY
    o   At the time of this review, no data were available to
        assess the mutagenic or genotoxic potential of this
        agent.                              

  o   No methods for measurement of sulfur trioxide in
      biological samples were listed in available references at
      the time of this review.
  o   If respiratory tract irritation or respiratory depression
      is evident, monitor arterial blood gases, chest x-ray, and
      pulmonary function tests.

  SUMMARY EXPOSURE
    o   Induced emesis is not indicated.  Dilution with small
        amounts of fluids may be of some use.  Patients should
        be evaluated for oral and esophageal burns.  Do not use
        neutralizing solutions by mouth.  Treatment is primarily
        symptomatic.
  ORAL EXPOSURE
    o   DO NOT INDUCE VOMITING - or give bicarbonate to
        neutralize.  Activated charcoal is of no value.  Gastric
        lavage is not likely to be beneficial, and carries the
        risk of complications of bleeding or perforation.
    o   DILUTION:  Following ingestion and/or prior to gastric
        evacuation, immediately dilute with 4 to 8 ounces (120
        to 240 mL) of milk or water (not to exceed 15 mL/kg in a
        child).
    o   Evaluate for pharyngeal, esophageal, or gastric burns.
    o   In severe cases of gastrointestinal necrosis or
        perforation, surgical consultation should be obtained.
    o   Sucralfate may be useful in relieving symptomatology
        from acid-induced injury.
    o   Obtain a follow-up esophagogram and upper GI series to
        evaluate for the presence or absence of secondary
        scarring and/or stricture formation about 2 to 4 weeks
        following ingestion.
    o   Steroid use is debatable.  Dose is 1 to 2 mg/kg/day of
        prednisone or other equivalent steroid.
  INHALATION EXPOSURE
    o   INHALATION:  Move patient to fresh air.  Monitor for
        respiratory distress.  If cough or difficulty breathing
        develops, evaluate for respiratory tract irritation,
        bronchitis, or pneumonitis.  Administer oxygen and
        assist ventilation as required.  Treat bronchospasm with
        beta2  agonist and corticosteroid aerosols.
    o   Respiratory tract irritation, if severe, can progress to
        pulmonary edema which may be delayed in onset up to 24
        to 72 hours after exposure in some cases.
    o   If bronchospasm and wheezing occur, consider treatment
        with inhaled sympathomimetic agents.
    o   PULMONARY EDEMA (NONCARDIOGENIC):  Maintain ventilation
        and oxygenation and evaluate with frequent arterial
        blood gas or pulse oximetry monitoring.  Early use of
        PEEP and mechanical ventilation may be needed.
    o   If respiratory tract irritation or respiratory
        depression is evident, monitor arterial blood gases,
        chest x-ray, and pulmonary function tests.
    o   Carefully observe patients with inhalation exposure for
        the development of any systemic signs or symptoms and
        administer symptomatic treatment as necessary.
    o   Patients developing chronic obstructive pulmonary
        disease following severe acute overexposure or long-term
        exposure may benefit from bronchodilating medications
        and a regimen of respiratory therapy.
    o   Smoking should be highly discouraged, and further sulfur
        trioxide or other oxides of sulfur exposure should be
        avoided.
  EYE EXPOSURE
    o   DECONTAMINATION:  Irrigate exposed eyes with copious
        amounts of tepid water for at least 15 minutes.  If
        irritation, pain, swelling, lacrimation, or photophobia
        persist, the patient should be seen in a health care
        facility.
    o   Prolonged initial flushing and early ophthalmologic
        consultation are advisable.
  DERMAL EXPOSURE
    o   DECONTAMINATION:  Remove contaminated clothing and
        jewelry; wash  exposed area with copious amounts of
        water.  A physician may need to examine the area if
        irritation or pain persists.
    o   Treat dermal irritation or burns with standard topical
        therapy.  Patients developing dermal hypersensitivity
        reactions may require treatment with systemic or topical
        corticosteroids or antihistamines.
    o   Treatment of CHEMICAL BURNS may be required.  Refer to
        the TREATMENT/DERMAL EXPOSURE section in the main body
        of this document for more information.           

  o   The minimum lethal human dose to this agent has not been
      delineated.
  o   In volunteer studies, 0.08 to 1.25 ppm lead to respiratory
      stimulation; 5.2 ppm, a 20% increase in airway resistance
      was seen; 10 ppm caused coughing and throat irritation.

Antidote and Emergency Treatment:

For basic treatment: Establish a patent airway. Suction if necessary. Watch for signs of respiratory insufficiency and assist respirations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... Monitor for shock and treat if necessary ... For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with normal saline during transport ... Do not use emetics. Activated charcoal is not effective. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... Do not attempt to neutralize because of exothermic reaction. Cover skin burns with dry, sterile dressings after decontamination ... For advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in respiratory arrest. Early intubation, at the first sign of upper airway obstruction, may be necessary. Positive-pressure ventilation techniques with a bag-valve-mask device may be beneficial. Monitor cardiac rhythm and treat arrhythmias as necessary ... Start an IV with D5W TKO. Use lactated Ringer's if signs of hypovolemia are present. Watch for signs of fluid overload ... Consider drug therapy for pulmonary edema. For hypotension with signs of hypovolemia, administer fluid cautiously. Consider vasopressors if patient is hypotensive with a normal fluid volume. Watch for signs of fluid overload ... Use proparacaine hydrochloride to assist eye irrigation ...
[Bronstein, A.C., P.L. Currance; Emergency Care for Hazardous Materials Exposure. 2nd ed. St. Louis, MO. Mosby Lifeline. 1994. 149]**PEER REVIEWED**

Treatment includes the use of oxygen, decontamination with special attention to the eyes, and monitoring for hypoxic ischemia. Treatment should include use of beta-agonists for bronchospasm, repeat pulmonary function tests, and monitoring for delayed pulmonary edema. Steroids, antibiotics, and nebulized sodium bicarbonate have not been adequately studied.
[Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997. 1521]**PEER REVIEWED**

Animal Toxicity Studies:

Metabolism/Pharmacokinetics:

Pharmacology:

Environmental Fate & Exposure:

Environmental Fate:

Atmospheric Fate: Sulfur trioxide is a highly reactive gas, and in the presence of moisture in the air it is rapidly hydrated to sulfuric acid. In the air, therefore, it is sulfuric acid in the form of an aerosol that is found rather than sulfur trioxide, and in general, it is associated with other pollutants in droplets or solid particles extending over a wide range of sizes.
[Waller, RE; Int J Air Water Pollut 7: 773-8 (1963) as cited in WHO; Environ Health Criteria: Sulfur Oxides and Suspended Particulate Matter p.17 (1979)]**PEER REVIEWED**

Environmental Standards & Regulations:

Chemical/Physical Properties:

Molecular Formula:

O3-S
[The Merck Index. 10th ed. Rahway, New Jersey: Merck Co., Inc., 1983. 1289]**PEER REVIEWED**

Molecular Weight:

80.064
[Lide, D.R. (ed.). CRC Handbook of Chemistry and Physics. 76th ed. Boca Raton, FL: CRC Press Inc., 1995-1996.,p. 4-88]**PEER REVIEWED**

Color/Form:

Alpha-form , asbestos-like needles
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

Beta-form, asbestos-like neeedles
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

Gamma-form, ice-like mass or liquid
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

Pure sulfur trioxide is a colorless liquid that fumes in air at room temperature and pressure.
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 365]**PEER REVIEWED**

Boiling Point:

45 deg C
[Lide, D.R. (ed.). CRC Handbook of Chemistry and Physics. 76th ed. Boca Raton, FL: CRC Press Inc., 1995-1996.,p. 4-88]**PEER REVIEWED**

Melting Point:

16.8 deg C
[Lide, D.R. (ed.). CRC Handbook of Chemistry and Physics. 76th ed. Boca Raton, FL: CRC Press Inc., 1995-1996.,p. 4-88]**PEER REVIEWED**

Corrosivity:

Absolute dry sulfur trioxide is not corrosive to metals
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

Critical Temperature & Pressure:

Critical temp: 217.8 deg C; critical pressure: 8,208 kPa
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 366]**PEER REVIEWED**

Solubilities:

Slowly very sol in aqueous, and sol in 100 parts water at room temp
[Dean, J.A. Handbook of Organic Chemistry. New York, NY: McGraw-Hill Book Co., 1987.,p. 2-29]**PEER REVIEWED**

Other Chemical/Physical Properties:

Melted sulfur trioxide exists in the gamma form and on solidifying tends to the alpha form. Absolutely dry sulfur trioxide shows no acid reaction.
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1516]**PEER REVIEWED**

Vitreous, orthorhombic; density: liquid: 1.920 at 20 deg C & solid: 2.29 at -10 deg C; melting point: 16.8 deg C; boiling point: 44.8 deg C; decomposes in cold & hot water; forms fuming sulfuric acid /Gamma form/
[Weast, R.C. (ed.) Handbook of Chemistry and Physics. 69th ed. Boca Raton, FL: CRC Press Inc., 1988-1989.,p. B-136]**PEER REVIEWED**

Silk fiber needles; melting point: 16.83 deg C; boiling point: 44.8 deg C; decomposes in cold & hot water; forms fuming sulfuric acid /Alpha form/
[Weast, R.C. (ed.) Handbook of Chemistry and Physics. 69th ed. Boca Raton, FL: CRC Press Inc., 1988-1989.,p. B-136]**PEER REVIEWED**

Asbestos like fiber; molecular formula: (SO3)2; molecular wt: 160.12; melting point: 62.4 deg C; boiling point: 50 deg C (sublimes); decomposes in cold & hot water; forms fuming sulfuric acid /Beta form/
[Weast, R.C. (ed.) Handbook of Chemistry and Physics. 69th ed. Boca Raton, FL: CRC Press Inc., 1988-1989.,p. B-136]**PEER REVIEWED**

Vapor pressure: 433 mm Hg at 25 deg C /Gamma form/
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

Sulfan A consists largely of beta sulfur trioxide and melts at 30-35 deg C; Sulfan B consists largely of gamma sulfur trioxide and melts at 17 deg C.
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

Heat of dilution: 504 cal/g
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

Oxidizing agent
[Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 12th ed. New York, NY: Van Nostrand Rheinhold Co., 1993 1105]**PEER REVIEWED**

Heat of hydration: 2.1 kJ/g
[Bretherick, L. Handbook of Reactive Chemical Hazards. 3rd ed. Boston, MA: Butterworths, 1985. 1366]**PEER REVIEWED**

Critical density: 0.630 g/cu cm
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 366]**PEER REVIEWED**

Solid density: 2.29 g/cu cm at -10 deg C /Gamma phase/
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 366]**PEER REVIEWED**

Liquid density: 1.9224 g/cu cm at 20 deg C /Gamma phase/
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 366]**PEER REVIEWED**

Liquid heat capacity: 3.222 kJ/kg deg C at 30 deg C
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 366]**PEER REVIEWED**

Heat of formation of gas: -395.76 MJ kg/mol at 25 deg C
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 366]**PEER REVIEWED**

Free energy of formation of gas: -371.07 MJ kg/mol at 25 deg C
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 366]**PEER REVIEWED**

Entropy of gas: 0.25666 MJ kg/mole deg C at 25 deg C
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 366]**PEER REVIEWED**

Heat of dilution: 2.109 MJ/kg
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 366]**PEER REVIEWED**

Heat of fusion: 324.0 kJ/kg /Alpha form/; 151.6 kJ/kg /Beta form/; 94.07 kJ/kg /Gamma form/
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 366]**PEER REVIEWED**

Heat of sublimation: 0.8518 MJ/kg /Alpha form/; 0.7269 MJ/kg /Beta form/; 0.7029 MJ/kg /Gamma form/
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 366]**PEER REVIEWED**

Heat of vaporization: 0.5843 MJ/kg /Gamma liquid/
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 366]**PEER REVIEWED**

Diffusion in air: 0.000013 m/sec at 80 deg C; liquid dielectric constant: 3.11 at 18 deg C; electric conductivity: negligible
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 366]**PEER REVIEWED**

Colorless to white crystalline solid, fuming in air /Sulfur trioxide, stabilized/
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, D.C.: Assoc. of American Railroads,Hazardous Materials Systems (BOE), 1987. 660]**PEER REVIEWED**

Vapor Pressure: 344 mm Hg at 25 deg C /Beta form/
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

73 mm Hg at 25 deg C /Alpha form/
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

Chemical Safety & Handling:

Hazards Summary:

The major hazards encountered in the use and handling of sulfur trioxide stem from its toxicologic properties and reactivity. Toxic by all routes (ie, inhalation, ingestion, and dermal contact), exposure to this colorless-to-white, crystalline solid may occur from its use in the sulfonation of oils and detergents, in the manufacture of sulfuric acid and explosives, and in solar energy collectors. Effects from exposure may include burns to the eyes, skin, and mucous membranes, shortness-of-breath, chest pain, and pulmonary edema. In activities and situations where over-exposure may occur, wear chemical protective clothing and a self-contained breathing apparatus. If contact should occur, irrigate exposed eyes with copious amounts of tepid water for at least 15 minutes, and wash exposed skin thoroughly with soap and water. Contaminated clothing should be removed and left at the worksite for cleaning. While sulfur trioxide itself burns with great difficulty, it may react violently (explosively) with water, giving off heat and light. Also, organic materials, particularly those containing adsorbed or absorbed moisture, may be ignited by sulfur trioxide. For fires involving sulfur trioxide, extinguish with agent suitable for surrounding materials. If water is used, apply in flooding quantities as a fog, and from as far a distance as possible. Use dikes to prevent sulfur trioxide from entering water sources and sewers. Sulfur trioxide may be shipped domestically via air (cargo only), rail (cargo only), road, and water, in containers bearing the label, "Corrosive." Sulfur trioxide should be stored in air-tight containers, away from moisture. Before implementing land disposal of sulfur trioxide waste, consult with environmental regulatory agencies for guidance.
**QC REVIEWED**

DOT Emergency Guidelines:

Health: TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance may cause severe injury, burns, or death. Fire will produce irritating, corrosive and/or toxic gases. Reaction with water may generate much heat which will increase the concentration of fumes in the air. Contact with molten substance may cause severe burns to skin and eyes. Runoff from fire control or dilution water may cause pollution. /Sulfur trioxide; Sulfur trioxide, inhibited; Sulfur trioxide, stabilized; Sulfur trioxide, uninhbited/
[U.S. Department of Transportation. 1996 North American Emergency Response Guidebook. A Guidebook for First Responders During the Initial Phase of aHazardous Materials/Dangerous Goods Incident. U.S. Department of Transportation (U.S. DOT) Research and Special Programs Administration, Office of HazardousMaterials Initiatives and Training (DHM-50), Washington, D.C. (1996).,p. G-137]**PEER REVIEWED**

Fire or explosion: Some of these materials may burn, but none ignite readily. May ignite combustibles (wood, paper, oil, clothing, etc.). Substance will react with water (some violently), releasing corrosive and/or toxic gases. Flammable/toxic gases may accumulate in confined areas (basement, tanks, hopper/tank cars etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated or if contaminated with water. Substance may be transported in a molten form. /Sulfur trioxide; Sulfur trioxide, inhibited; Sulfur trioxide, stabilized; Sulfur trioxide, uninhbited/
[U.S. Department of Transportation. 1996 North American Emergency Response Guidebook. A Guidebook for First Responders During the Initial Phase of aHazardous Materials/Dangerous Goods Incident. U.S. Department of Transportation (U.S. DOT) Research and Special Programs Administration, Office of HazardousMaterials Initiatives and Training (DHM-50), Washington, D.C. (1996).,p. G-137]**PEER REVIEWED**

Public safety: CALL Emergency Response Telephone Number. ... Isolate spill or leak area immediately for at least 50 to 100 meters (160 to 330 feet) in all directions. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate enclosed areas. /Sulfur trioxide; Sulfur trioxide, inhibited; Sulfur trioxide, stabilized; Sulfur trioxide, uninhbited/
[U.S. Department of Transportation. 1996 North American Emergency Response Guidebook. A Guidebook for First Responders During the Initial Phase of aHazardous Materials/Dangerous Goods Incident. U.S. Department of Transportation (U.S. DOT) Research and Special Programs Administration, Office of HazardousMaterials Initiatives and Training (DHM-50), Washington, D.C. (1996).,p. G-137]**PEER REVIEWED**

Protective clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing which is specifically recommended by the manufacturer. Structural firefighters' protective clothing is recommended for fire situations ONLY; it is not effective in spill situations. /Sulfur trioxide; Sulfur trioxide, inhibited; Sulfur trioxide, stabilized; Sulfur trioxide, uninhbited/
[U.S. Department of Transportation. 1996 North American Emergency Response Guidebook. A Guidebook for First Responders During the Initial Phase of aHazardous Materials/Dangerous Goods Incident. U.S. Department of Transportation (U.S. DOT) Research and Special Programs Administration, Office of HazardousMaterials Initiatives and Training (DHM-50), Washington, D.C. (1996).,p. G-137]**PEER REVIEWED**

Evacuation: ... Fire: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. /Sulfur trioxide; Sulfur trioxide, inhibited; Sulfur trioxide, stabilized; Sulfur trioxide, uninhbited/
[U.S. Department of Transportation. 1996 North American Emergency Response Guidebook. A Guidebook for First Responders During the Initial Phase of aHazardous Materials/Dangerous Goods Incident. U.S. Department of Transportation (U.S. DOT) Research and Special Programs Administration, Office of HazardousMaterials Initiatives and Training (DHM-50), Washington, D.C. (1996).,p. G-137]**PEER REVIEWED**

Fire: When material is not involved in fire: do not use water on material itself. Small fires: Dry chemical or C02. Move containers from fire area if you can do it without risk. Large Fires: Flood fire area with large quantities of water, while knocking down vapors with water fog. If insufficient water supply: knock down vapors only. Fire involving tanks or car/trailer loads: Cool containers with flooding quantities of water until well after fire is out. Do not get water inside containers. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from the ends of tanks. /Sulfur trioxide; Sulfur trioxide, inhibited; Sulfur trioxide, stabilized; Sulfur trioxide, uninhbited/
[U.S. Department of Transportation. 1996 North American Emergency Response Guidebook. A Guidebook for First Responders During the Initial Phase of aHazardous Materials/Dangerous Goods Incident. U.S. Department of Transportation (U.S. DOT) Research and Special Programs Administration, Office of HazardousMaterials Initiatives and Training (DHM-50), Washington, D.C. (1996).,p. G-137]**PEER REVIEWED**

Spill or leak: Fully encapsulating, vapor protective clothing should be worn for spills and leaks with no fire. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Use water spray to reduce vapors; do not put water directly on leak, spill area or inside container. Keep combustibles (wood, paper, oil, etc.) away from spilled material. Small spills: Cover with DRY earth, DRY sand, or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain. Use clean non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal. Prevent entry into waterways, sewers, basements or confined areas. /Sulfur trioxide; Sulfur trioxide, inhibited; Sulfur trioxide, stabilized; Sulfur trioxide, uninhbited/
[U.S. Department of Transportation. 1996 North American Emergency Response Guidebook. A Guidebook for First Responders During the Initial Phase of aHazardous Materials/Dangerous Goods Incident. U.S. Department of Transportation (U.S. DOT) Research and Special Programs Administration, Office of HazardousMaterials Initiatives and Training (DHM-50), Washington, D.C. (1996).,p. G-137]**PEER REVIEWED**

First aid: Move victim to fresh air. Call emergency medical care. Apply artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; induce artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult. Remove and isolate contaminated clothing and shoes. In case of contact with substance, immediately flush skin or eyes with running water for at least 20 minutes. For minor skin contact, avoid spreading material on unaffected skin. Removal of solidified molten material from skin requires medical assistance. Keep victim warm and quiet. Effects of exposure (inhalation, ingestion or skin contact) to substance may be delayed. Ensure that medical personnel are aware of the material(s) involved, and take precautions to protect themselves. /Sulfur trioxide; Sulfur trioxide, inhibited; Sulfur trioxide, stabilized; Sulfur trioxide, uninhbited/
[U.S. Department of Transportation. 1996 North American Emergency Response Guidebook. A Guidebook for First Responders During the Initial Phase of aHazardous Materials/Dangerous Goods Incident. U.S. Department of Transportation (U.S. DOT) Research and Special Programs Administration, Office of HazardousMaterials Initiatives and Training (DHM-50), Washington, D.C. (1996).,p. G-137]**PEER REVIEWED**

Skin, Eye and Respiratory Irritations:

Irritant ... to mucous membranes.
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

Sulfur trioxide ... causes great irritation of the eyes and resp tract, even at concn as low as 1 ppm in air.
[Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986. 868]**PEER REVIEWED**

Fire Potential:

Material itself does not burn or burns with difficulty.
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, DC: Association of American Railroads, Bureau of Explosives, 1994. 1018]**PEER REVIEWED**

Fire Fighting Procedures:

If material involved in fire: Extinguish fire using agent suitable for type of surrounding fire. ... Use water in flooding quantities as fog. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible.
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, DC: Association of American Railroads, Bureau of Explosives, 1994. 1018]**PEER REVIEWED**

Explosive Limits & Potential:

Heating of high melting sulfur trioxide in glass vessels should be avoided to prevent possible shattering of the container.
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

Hazardous Reactivities & Incompatibilities:

On exposure to air, it absorbs moisture rapidly, emitting dense white fumes. Combines with water with explosive violence ... forming sulfuric acid.
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

Dissolution of sulfur trioxide in ... /dimethyl/ sulfoxide is very exothermic and must be done slowly with cooling to avoid decomp.
[Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990 1424]**PEER REVIEWED**

... The 1:1 addition complex /dioxane & sulfur trioxide/ sometimes decomp violently on storing at ambient temp ...
[Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990 1424]**PEER REVIEWED**

The violent interaction with sulfur trioxide causes incandescence with barium oxide and lead oxide.
[Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990 1424]**PEER REVIEWED**

Organic materials, particularly if fibrous with adsorbed or absorbed moisture present, may char or ignite in contact with the stabilized liquid form because of the very high heat of hydration ... and formation of hot oleum which then functions as an oxidant.
[Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990 1425]**PEER REVIEWED**

Reaction /of tetrafluoroethylene/ ... with excess sulfur trioxide may cause explosive decomp to carbonyl fluoride and sulfur dioxide.
[Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990 1425]**PEER REVIEWED**

Interaction /with water/ is vigorously exothermic, sometimes explosive, with evolution of light and heat.
[Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990 1425]**PEER REVIEWED**

Interaction of the endothermic fluoride with the trioxide is very vigorous, and explosive in absence of solvent.
[Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990 1110]**PEER REVIEWED**

... Sulfur trioxide /reacts/ very violently ... with diphenylmercury.
[Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990 840]**PEER REVIEWED**

Bottles containing a modified Karl Fischer reagent /iodine, pyridine, sulfur trioxide/ with formamide replacing methanol developed gas pressure during several months and burst.
[Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990 161]**PEER REVIEWED**

White phosphorus ignites after some delay in contact with the vapor of sulfur trioxide, but immediately in contact with the liquid if large portion is used.
[Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990 1438]**PEER REVIEWED**

Liquid sulfur trioxide reacts violently with nitryl chloride, even at 75 deg C.
[National Fire Protection Guide. Fire Protection Guide on Hazardous Materials. 10 th ed. Quincy, MA: National Fire Protection Association, 1991.,p. 491M-144]**PEER REVIEWED**

The reaction of anhydrous perchloric acid with sulfur trioxide is violent and accompanied by the evolution of considerable heat, even when diluted with an inert solvent such as chloroform.
[National Fire Protection Guide. Fire Protection Guide on Hazardous Materials. 10 th ed. Quincy, MA: National Fire Protection Association, 1991.,p. 491M-154]**PEER REVIEWED**

Protective Equipment & Clothing:

Wear positive pressure self contained breathing apparatus. Wear appropriate chemical protective clothing.
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, DC: Association of American Railroads, Bureau of Explosives, 1994. 1018]**PEER REVIEWED**

Preventive Measures:

If material not involved in fire: Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Use water spray to knock down vapors.
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, DC: Association of American Railroads, Bureau of Explosives, 1994. 1018]**PEER REVIEWED**

Personnel protection: Avoid breathing vapors. Keep upwind. Avoid bodily contact with the material. Do not handle broken packages unless wearing appropriate personal protective equipment. Wash away any material which may have contacted the body with copious amounts of water or soap and water.
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, DC: Association of American Railroads, Bureau of Explosives, 1994. 1018]**PEER REVIEWED**

Contact lenses should not be worn when working with this chemical. /Sulfur dioxide/
[NIOSH. Pocket Guide to Chemical Hazards. 2nd Printing. DHHS (NIOSH) Publ. No. 85-114. Washington, D.C.: U.S. Dept. of Health and Human Services, NIOSH/Supt.of Documents, GPO, February 1987. 212]**PEER REVIEWED**

SRP: Contaminated protective clothing should be segregated in such a manner so that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. Quality assurance to ascertain the completeness of the cleaning procedures should be implemented before the decontaminated protective clothing is returned for reuse by the workers. Contaminated clothing should not be taken home at end of shift, but should remain at employee's place of work for cleaning.
**PEER REVIEWED**

SRP: The scientific literature for the use of contact lenses in industry is conflicting. The benefit or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.
**PEER REVIEWED**

Stability/Shelf Life:

The alpha form is the stable modification, the beta & gamma forms are metastable.
[The Merck Index. 10th ed. Rahway, New Jersey: Merck Co., Inc., 1983. 1289]**PEER REVIEWED**

Shipment Methods and Regulations:

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./
[49 CFR 171.2 (7/1/96)]**PEER REVIEWED**

The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials.
[IATA. Dangerous Goods Regulations. 38th ed. Montreal, Canada and Geneva, Switzerland: International Air Transport Association, Dangerous Goods Board, January, 1997. 217]**PEER REVIEWED**

The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article.
[IMDG; International Maritime Dangerous Goods Code; International Maritime Organization p.8223 (1988)]**PEER REVIEWED**

Storage Conditions:

/When/ stabilized, must be kept warm to liquefy, but under 40 deg C.
[Kuney, J.H. and J.N. Nullican (eds.) Chemcyclopedia. Washington, DC: American Chemical Society, 1988. 216]**PEER REVIEWED**

Disposal Methods:

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.
**PEER REVIEWED**

Occupational Exposure Standards:

Other Occupational Permissible Levels:

Emergency Response Planning Guidelines (ERPG): ERPG(1) 2 mg/cu m (no more than mild, transient effects) for up to 1 hr exposure; ERPG(2) 10 mg/cu m (without serious, adverse effects) for up to 1 hr exposure; ERPG(3) 30 mg/cu m (not life threatening) up to 1 hr exposure.
[American Industrial Hygiene Association. The AIHA 1999 Emergency Response Planning Guidelines and Workplace Environmental Exposure Level Guides Handbook.American Industrial Hygiene Association. Fairfax, VA 1999. 26]**QC REVIEWED**

Manufacturing/Use Information:

Major Uses:

Intermediate in sulfuric acid manufacture; in sulfonations for formation of addition cmpd with amines; in the manufacture of explosives
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

Sulfonation of organic compounds, especially non ionic detergents; solar energy collectors
[Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 12th ed. New York, NY: Van Nostrand Rheinhold Co., 1993 1105]**PEER REVIEWED**

Sulfur trioxide is used as such for preparing sulfonated oils, and alkyl arenesulfonate detergents.
[Cotton FA, Wilkinson G; Advanced Inorganic Chemistry 4th Ed p.529 (1980)]**PEER REVIEWED**

... Used as a powerful, but generally indiscriminate oxidizing agent, however, it will selectively oxidize pentachlorotoluene and similar compounds to the alcohol.
[Cotton FA, Wilkinson G; Advanced Inorganic Chemistry 4th Ed p.529 (1980)]**PEER REVIEWED**

Manufacturers:

EI du Pont de Nemours & Company, Inc, Hq, 1007 Market Street, Wilmington, DE 19898, (302) 774-1000; Production sites: DuPont Specialty Chemicals, Linden, NJ 07036; DuPont Performance, Specialty and Fine Chemicals: Northbend, OH 45052; Wurtland, KY 41144
[SRI. 1997 Directory of Chemical Producers - United States of America. Menlo Park, CA: SRI International 1997. 911]**PEER REVIEWED**

PVS Chemicals Inc., 12260 South Carondolet Chicago, IL 60633 (773) 933-880. Production site: Chicago, IL 60603
[SRI. 1997 Directory of Chemical Producers - United States of America. Menlo Park, CA: SRI International 1997. 911]**PEER REVIEWED**

Rhone-Poulenc Inc., CN 5266, Princeton, NJ 08543-5266 (908) 297-0100; Production site: Hammond, IN 46320
[SRI. 1997 Directory of Chemical Producers - United States of America. Menlo Park, CA: SRI International 1997. 911]**PEER REVIEWED**

Methods of Manufacturing:

Prepared by the contact process, for example, by the action of oxygen on sulfur dioxide in the presence of catalysts such as platinized asbestos, platinized magnesium sulfate, ferric oxide or vanadium cmpd.
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

... Obtained by reaction of sulfur dioxide with molecular oxygen.
[Cotton FA, Wilkinson G; Advanced Inorganic Chemistry 4th Ed p.529 (1980)]**PEER REVIEWED**

Liquid sulfur trioxide is produced by heating oleum in a boiler to generate SO3 gas which is then condensed.
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 379]**PEER REVIEWED**

May be prepared in the laboratory by heating fuming sulfuric acid and collecting the subliminate in a cooled receiver. If the vapor is condensed above 27 deg C, the gamma form is obtained as a liquid. If the vapor is condensed below 27 deg C and in the presence of a trace of moisture, a mixture of all 3 forms is obtained. The 3 forms can be separated by fractional distillation.
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

Formulations/Preparations:

Under the trademark Sulfan, a product is marketed which contains 0.5% of a stabilizer to prevent polymerization to higher melting forms: Sulfan A consists largely of beta sulfur trioxide ... Sulfan B consists largely of gamma sulfur trioxide ... Sulfan C contains no stabilizer and will polymerize to alpha sulfur trioxide.
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

Stabilizers added include: 0.3% dimethyl sulfate with 0.005% boric oxide
[Kirk-Othmer Encyclopedia of Chemical Technology. 3rd ed., Volumes 1-26. New York, NY: John Wiley and Sons, 1978-1984.,p. 22(83) 215]**PEER REVIEWED**

Stabilized, technical, liquid grades
[Kuney, J.H. and J.N. Nullican (eds.) Chemcyclopedia. Washington, DC: American Chemical Society, 1988. 216]**PEER REVIEWED**

Impurities:

Trace amounts of water or sulfuric acid can catalyze the formation of polymers.
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 366]**PEER REVIEWED**

Consumption Patterns:

Its principle applications are in production of detergents and as a raw material for chlorosulfuric acid and 65% oleum. (1983)
[Kirk-Othmer Encyclopedia of Chemical Technology. 3rd ed., Volumes 1-26. New York, NY: John Wiley and Sons, 1978-1984.,p. 22(83) 215]**PEER REVIEWED**

Laboratory Methods:

Special References:

Special Reports:

WHO; Environ Health Criteria: Sulfur Oxides and Suspended Particulate Matter (1979)

Nat'l Research Council Canada; Sulfur and Its Inorganic Derivatives p.289-90 (1977) NRCC No.15015

Synonyms and Identifiers:

Synonyms:

Sulfan
**PEER REVIEWED**

Sulfuric anhydride
**PEER REVIEWED**

Sulfur oxide
**PEER REVIEWED**

Sulfur trioxide, stabilized
**PEER REVIEWED**

Formulations/Preparations:

Under the trademark Sulfan, a product is marketed which contains 0.5% of a stabilizer to prevent polymerization to higher melting forms: Sulfan A consists largely of beta sulfur trioxide ... Sulfan B consists largely of gamma sulfur trioxide ... Sulfan C contains no stabilizer and will polymerize to alpha sulfur trioxide.
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 1536]**PEER REVIEWED**

Stabilizers added include: 0.3% dimethyl sulfate with 0.005% boric oxide
[Kirk-Othmer Encyclopedia of Chemical Technology. 3rd ed., Volumes 1-26. New York, NY: John Wiley and Sons, 1978-1984.,p. 22(83) 215]**PEER REVIEWED**

Stabilized, technical, liquid grades
[Kuney, J.H. and J.N. Nullican (eds.) Chemcyclopedia. Washington, DC: American Chemical Society, 1988. 216]**PEER REVIEWED**

Shipping Name/ Number DOT/UN/NA/IMO:

UN 1829; Sulfur trioxide, inhibited, uninhibited

IMO 8.0; Sulfur trioxide, inhibited

IMO 2.0; Sulfur trioxide, uninhibited

Standard Transportation Number:

49 300 50; Sulfur trioxide, stabilized

RTECS Number:

NIOSH/WT4830000

Administrative Information:

Hazardous Substances Databank Number: 6338

Last Revision Date: 20010809

Last Review Date: Reviewed by SRP on 1/31/1998

Update History:

Complete Update on 08/09/2001, 1 field added/edited/deleted.
Complete Update on 09/12/2000, 1 field added/edited/deleted.
Complete Update on 02/08/2000, 1 field added/edited/deleted.
Complete Update on 09/21/1999, 1 field added/edited/deleted.
Complete Update on 05/11/1999, 1 field added/edited/deleted.
Complete Update on 06/05/1998, 35 fields added/edited/deleted.
Field Update on 03/10/1998, 1 field added/edited/deleted.
Field Update on 11/01/1997, 1 field added/edited/deleted.
Complete Update on 02/28/1997, 1 field added/edited/deleted.
Complete Update on 10/20/1996, 1 field added/edited/deleted.
Complete Update on 01/31/1996, 1 field added/edited/deleted.
Complete Update on 01/12/1995, 1 field added/edited/deleted.
Complete Update on 09/01/1994, 2 fields added/edited/deleted.
Field Update on 03/29/1994, 1 field added/edited/deleted.
Field update on 01/13/1993, 1 field added/edited/deleted.
Complete Update on 10/28/1992, 2 fields added/edited/deleted.
Field Update on 04/03/1992, 1 field added/edited/deleted.
Complete Update on 08/14/1990, 42 fields added/edited/deleted.
Complete Update on 04/22/1988, 23 fields added/edited/deleted.

Record Length: 58418