It’s not JUST Smoke!The Truth about Fire Smoke
Smoke:
“An aerosol of solid or liquid particles usually resulting from incomplete combustion.”
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Anatomy of Fire Smoke• Particulates
• Dust• Soot
• Irritants• Hydrochloric acid• Sulfur dioxide• Oxides of nitrogen• Ammonia
• Asphyxiants/Toxicants• Carbon dioxide• Hydrogen cyanide• Carbon monoxide• Hydrogen sulfide
Kulig K. N Engl J Med. 1991;325:1801-1802.Lee-Chiong TL. Postgrad Med. 1999;105:55-62.
Photo: Cyanide Poisoning Treatment Coalition (2006), Falls Church, VA.
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ToxicologyABSORPTION
Without it, a toxic substance does not present a human
health hazard
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ROUTES OF ENTRY
InhalationAbsorption Ingestion Injection
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Smoke ExposuresIt’s pretty simple -
•How Much?
•How Long?
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Oxides of Nitrogen - NOx
Deep lung irritant – may produce pulmonary edema
A by-product of high-temperature combustion, NOX is produced when Oxygen and Nitrogen combine
OSHA PEL: 5 ppm IDLH : 20 ppmTarget Organs: CVS, Respiratory
system
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Oxides of Nitrogen - NOx
- Strong irritants, particularly to mucous membranes. - When inhaled will damage tissues in the respiratory tract - Threshold limit value: 5ppm- Least amount causing immediate irritation to the throat: 62
ppm- Dangerous for short exposure: 117 to 154 ppm- Rapidly fatal for short exposure: 240 to 775 ppm
Oxides of Nitrogen - NOx
• Severe cases of non-cardiogenic pulmonary edema: up to 2 liters of fluid in the lungs.• Onset can be delayed
up to 6 hours
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FormaldehydeFormaldehyde• Water soluble• Heavier than air• Flammable• Gas at room temp• Probable human carcinogen• Sources: resins, plastics, preservatives,
drying agent, tobacco smoke
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FormaldehydeFormaldehyde
Acute health effects: Inflammation of lungs and respiratory
tract, pulmonary edema.2-3 ppm: nasal irritation20-30 ppm: Breathing is difficult (IDLH)50-100 ppm: Serious injury; pulmonary
edema
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Vinyl Chloride
Key component of plastics industry (PVC)
Known carcinogen
Affects liver, CNS, lymphatic systemToxic by inhalation and absorptionOSHA PEL: 1ppm
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Poly Vinyl Chloride• Wire insulation, electrical conduit, plumbing pipe,
molded plastic furniture, etc.• Decomposition temperature: 450-500 degrees F
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Do you think it’s a reasonable proposition to inhale microscopic
shards of glass coated with phenol-formaldehyde?
Fiberglass – SMF’s
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Particulates - Soot
- Byproduct of incomplete combustion
- Known human carcinogen; lung cancer
- PAH’s – polycyclic aromatic hydrocarbons
OSHA PEL: 0.2 mg/m3Toxic by inhalation, ingestion
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Carbon Monoxide• Poisonous, colorless, odorless, tasteless and highly flammable
• Flammable Range: 12%-74%
• Present in incomplete combustion
• OSHA PEL: 50 ppm - IDLH : 1200ppm• Target Organs: CVS, Blood, CNS
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• Cyanide produced by combustion of both synthetic and natural substances• Most common source of
acute cyanide poisoning in the US• Contributes significantly
to smoke inhalation injury and death
Fire Smoke A Source of Cyanide
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• Natural substances• Wool• Silk• Cotton • Paper
• Synthetic substances• Plastics • Other polymers
Plastics
Sources of Cyanide in Fire Smoke
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Cyanide Compounds10 ppm: Threshold limit value
20-40 ppm: Slight Symptoms after several hours
of exposure
50-60 ppm: Maximum amount that can be inhaled
for1 hour without serious disturbance
120-150 ppm: Dangerous in 30 minutes to 1 hour
3000 ppm: Rapidly fatal
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Cyanide Compounds• Half-life of cyanide in the body is about 1 hour
• Cannot be detected by smell in 40%-60% of the population
• Deficit is greater in men by 3:1
• 35 times more toxic than CO
HCN – An Invisible Threat . . .
Absence of a rapidly returnable diagnostic test for cyanide poisoning reinforces the perception of carbon monoxide as the primary contributor to smoke inhalation injuries and deaths.
Eckstein M, Maniscalco PM. Prehosp Disast Med. 2005;21:s49-s55.Watson WA, et al. 2004 Annual Report of the American Association of Poison Control Centers
Toxic Exposure Surveillance System.
. . . or Just Ignored?• Substrates for hydrogen cyanide frequently
found in modern buildings (natural and synthetic substances containing carbon and nitrogen, such as wool, silk, and some plastics)• Release of hydrogen cyanide highly probable
and to be expected in enclosed-space fires• Cyanide can act independently from carbon
monoxide
Eckstein M, Maniscalco PM. Prehosp Disast Med. 2005;21:s49-s55.Alaire Y. Critical Reviews in Toxicology. 2002;32;259-289.
Flomenbaum NE, et al. Goldfrank’s Toxicologic Emergencies. McGraw-Hill. 2006.
Toxicity of Fire Smoke: Conclusions
• Cyanide is likely to be present in appreciable amounts in fire victims’ blood
• Cyanide is a common product of combustion – which is treatable if diagnosed.
• Frequent co-exposure to carbon monoxide and cyanide occurs
• Although carbon monoxide is likely a major toxicant in fires, cyanide can sometimes be the principal cause of death
• Numerous deadly toxicants exist in toxic fire smoke, which if exposed acutely or chronically (NOT ON AIR) – can cause disease or death.
Alaire Y. Critical Reviews in Toxicology. 2002;32:259-289.
Questions & Answers
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