Sulfur Dioxide (SO2)

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Sulfur Dioxide (SO2)
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Sulfur Dioxide - Overview

• Physical properties
• Colorless, non-flammable gas
• Heavier than air
• Strong, suffocating odor
• Rotting eggs
• Liquid under pressure
• Readily soluble in water

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Sulfur Dioxide - Overview

• Over 13 million tons released each year from
  electric power plants
• Primary environmental source burning of fossil
  fuels
• Major component of acid rain
• Occurs naturally from the decay of vegetation

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Sulfur Dioxide - Overview

• Industrial use
• Useful to terrorists seeking to spread fear and
  disruption

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Sulfur Dioxide - Toxicity

• Major route of toxicity is inhalation
• Strong eye and skin irritant
• Asthmatics more susceptible
• Children more vulnerable
• Greater lung surface area to body weight ratio
• Increased minute ventilation per kg
• Short stature

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Sulfur Dioxide - Toxicity

• Acute exposures
• 5 ppm nose and throat dryness
• Airway restriction
• 6-8 ppm decrease in tidal volume
• 10 ppm sneezing, cough, expectoration, and eye
  symptoms
• 20 ppm severe bronchospasm
• 50 ppm upper respiratory symptoms

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Sulfur Dioxide - Toxicity

• 100 ppm immediate health risk
• 1000 ppm death from severe respiratory
  depression
• EPA
• Long-term 0.03 ppm, 1-year average
  concentrations
• Short-term, 24-hour concentrations
• Not to exceed 0.14 ppm more than once a year

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Sulfur Dioxide - Toxicity

• OSHA
• 2 ppm over an 8-hour workday, 40-hour work week
• 5 ppm for short-term exposure
• NIOSH IDLH 100 ppm

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Protective Equipment

• Positive-pressure, SCBA is advised
• Chemical-protective clothing for exposure to the
  liquefied gas
• Safety glasses, face shield, and rubber gloves
  provide adequate eye and skin protection

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Detection

• Distinct odor
• Olfactory fatigue does not occur rapidly
• Variety of monitors and gas sensors available
  commercially

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Decontamination

• Remove individuals from contaminated area
• Remove and double-bag contaminated clothing and
  personal belongings

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Decontamination

• Eye exposure
• Flush immediately with water
• Irrigate continuously with normal saline
• Proparacaine hydrochloride to assist eye
  irrigation

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Decontamination

• For skin exposure
• Flush with water
• Wash well with soap and water
• Cover burns with sterile dressings
• Avoid hypothermia in children and elderly

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Signs and Symptoms

• Adverse effects
• Increased by formation of sulfates or higher
  sulfur oxides
• Interactions with water and particulates
• Clinical diagnosis
• Intensely irritating to eyes and respiratory tract

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Signs and Symptoms

• Acute effects
• Upper respiratory tract irritation
• Rhinorrhea
• Choking
• Expectoration
• Nosebleeds
• Difficulty in swallowing
• Oropharyngeal erythema
• Coughing

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Signs and Symptoms

• Within 5 - 15 minutes
• Temporary reflex bronchoconstriction
• Increased airway resistance
• Pulmonary infection from destruction of the
  ciliated epithelium
• Asphyxiation from severe glottal and bronchiolar
  constriction

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Signs and Symptoms

• Eyes
• Lacrimation, conjunctival injection, and
  blepharitis
• Higher exposures iritis

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Signs and Symptoms

• Severe eye injury
• Liquid form of SO2
• Corneal epithelium turns gray and irregular
  remaining attached to stroma
• Lids become edematous and conjunctiva appears
  white and opaque
• Blindness may result

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Signs and Symptoms

• Dermal exposure
• Irritation, urticarea, and burns
• Major risk liquid sulfur dioxide exposure

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Signs and Symptoms

• Metabolic acidosis
• Blood alkali reserves reduction
• Ammonia elimination in urine
• Protein and carbohydrate metabolism disorders,
  along with possible
• Effects the hemopoietic system and methemoglobin
  production

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Signs and Symptoms

• Chronic exposure
• Permanent pulmonary impairment
• Repeated bronchoconstriction episodes

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Treatment

• Basic first aid for victims
• No antidote
• Care is supportive
• Monitor the cardiac rhythm
• Treat arrhythmias
• Precautionary intravenous line
• Hypovolemia or shock
• Use normal saline consider vasopressors

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Treatment

• Acidotic patient
• Anticipate seizures
• Treat with diazepam
• Treat skin irritation and burns topically

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Treatment

• Establish patent airway
• Intubate for upper airway obstruction
• Maintain open airway with suctioning as necessary
  
• Consider assisted ventilation

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Treatment

• Correct hypoxia with oxygen
• Non-rebreather mask
• Monitor the patients oxygenation status
• Arterial blood gases or pulse oximetry
• Watch for signs of pulmonary edema
• IPPB, PEEP, or intubation

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Treatment

• For ingestions
• Rinse mouth, administer water for dilution
• DO NOT use emetics
• Administer activated charcoal as a slurry
• Consider a cathartic

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Long-Term Medical Sequelae

• Acute high-dose exposures
• Severe obstructive and restrictive defects
• High dose exposures (80 to 100 ppm)
• Nasopharyngitis, dyspnea on exertion, and chronic
  fatigue
• Lower exposures (2 to 36 ppm)
• Respiratory disease symptoms

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Long-Term Medical Sequelae

• No studies linking to cancer
• EPA classified as Group D
• Reproductive and teratogenetic effects not known

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Environmental Sequelae

• Converts to sulfuric acid, sulfur trioxide, and
  sulfates when released into air
• Dissolved in water
• Absorbed into soil

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Summary

• Readily available gas
• Terrorists may use to spread fear and disruption
• Exposures as low as 5 ppm
• Dryness of the nose and throat
• Increase in airway restriction
• Exposures at 100 ppm
• Dangerous to life and health

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Summary

• Acute effects
• Upper respiratory tract irritation
• Rhinorrhea
• Choking
• Expectoration
• Nosebleeds
• Dysphagia
• Oropharyngeal erythema and coughing
• Chemical bronchopneumonia, pulmonary edema,
  cyanosis, asphyxia and death

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Summary

• No antidote
• Care is supportive
• Most common cause of death is asphyxiation