Health Hazards of Health Hazards of GasesGases

A review of the toxicities of substances A review of the toxicities of substances that exist in the gaseous state under that exist in the gaseous state under

normal conditions of usenormal conditions of use

AsphyxiantsAsphyxiants

AsphyxiantsAsphyxiants Simple: replace oxygen Simple: replace oxygen Chemical: disrupt transport or use of oxygenChemical: disrupt transport or use of oxygen

HypoxiaHypoxia

Anoxia – Anoxia – Symptoms: euphoria, increased respiration & Symptoms: euphoria, increased respiration &

HR, headache, fatigue, unconsciousness, HR, headache, fatigue, unconsciousness, deathdeath

Oxygen DeficiencyOxygen Deficiency

The brain is very sensitive to oxygen The brain is very sensitive to oxygen deficiencydeficiencyNormal oxygen: 19.5 - 21.5%Normal oxygen: 19.5 - 21.5%Encountered in tanks, silos, mines, poorly Encountered in tanks, silos, mines, poorly ventilated spacesventilated spacesMan may be able to hold breath for ~ Man may be able to hold breath for ~ 1minute with normal levels of oxygen in 1minute with normal levels of oxygen in the air, but will collapse in seconds with the air, but will collapse in seconds with 5% oxygen.5% oxygen.

Carbon Monoxide (CO)Carbon Monoxide (CO)

Colorless, odorless, toxic gasColorless, odorless, toxic gasProduced by incomplete combustion of Produced by incomplete combustion of fossil fuelsfossil fuelsResponseResponse 50 PPM = PEL50 PPM = PEL 200 PPM = slight headache200 PPM = slight headache 400 PPM = frontal headache400 PPM = frontal headache 800 PPM = dizziness, nausea, convulsions, 800 PPM = dizziness, nausea, convulsions,

insensibleinsensible

Hydrogen Sulfide Hydrogen Sulfide

PropertiesProperties Foul odorFoul odor

No industrial use, but formed in many processes No industrial use, but formed in many processes and decay of sulfur-containing materialsand decay of sulfur-containing materials

Chronic effectsChronic effects Olfactory fatigue, eye irritation leading to “halo” and Olfactory fatigue, eye irritation leading to “halo” and

“blue fog” effects, no apparent long-term effects“blue fog” effects, no apparent long-term effects

Acute effectsAcute effects Rapidly oxidized in the blood, acts directly on Rapidly oxidized in the blood, acts directly on

respiratory control centerrespiratory control center

Hydrogen CyanideHydrogen Cyanide

Common source of cyanide poisoningCommon source of cyanide poisoning

Rapid absorption via inhalation and Rapid absorption via inhalation and through skinthrough skin

Rapid onset of symptomsRapid onset of symptoms Headache, nausea, weakness, confusion, Headache, nausea, weakness, confusion,

collapse, deathcollapse, death

Antidotes and chances of recoveryAntidotes and chances of recovery

IrritantsIrritants

Irritant – A substance producing an Irritant – A substance producing an irritating effect when it contacts the skin, irritating effect when it contacts the skin, eyes, nose, or eyes, nose, or respiratory system.respiratory system.

SolubilitySolubility Can influence the part of the respiratory tract Can influence the part of the respiratory tract

that is effectedthat is effected

Irritants of the Irritants of the Upper Respiratory TractUpper Respiratory Tract

Are highly soluble in waterAre highly soluble in water

Generally have good warning propertiesGenerally have good warning properties

Usually do NOT produce chronic effectsUsually do NOT produce chronic effects

Examples:Examples: AmmoniaAmmonia Ammonium hydroxideAmmonium hydroxide Acid gases (HF, HCl, HBr), sulfur oxidesAcid gases (HF, HCl, HBr), sulfur oxides

Irritants of the Irritants of the Lower Respiratory TractLower Respiratory Tract

Have low but significant water solubility or Have low but significant water solubility or hydrolyze in moist mucoushydrolyze in moist mucous

Usually are not irritating to breatheUsually are not irritating to breathe

Almost always produce delayed effectsAlmost always produce delayed effects

ExamplesExamples Nitrogen dioxideNitrogen dioxide PhosgenePhosgene

Irritants of the Irritants of the Whole Respiratory TractWhole Respiratory Tract

Have intermediate levels of solubilityHave intermediate levels of solubility

Produce some warning but not sufficientlyProduce some warning but not sufficiently

Can affect the whole respiratory systemCan affect the whole respiratory system

ExamplesExamples Halogens (fluorine, chlorine, bromine, iodine)Halogens (fluorine, chlorine, bromine, iodine) OzoneOzone

SummarySummary

Simple asphyxiantsSimple asphyxiants

Chemical asphyxiantsChemical asphyxiants

URT irritantsURT irritants

LRT irritantsLRT irritants

WRT irritantsWRT irritants

Asphyxiating irritantsAsphyxiating irritants ArsineArsine StibineStibine GermaneGermane