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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