Health Hazards

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Health Hazards

• Those hazards which may cause measurable changes
  in the body or its functions

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Hazards

• Physical
• Chemical
• Biological
• Ergonomic
• Psychosocial
• Other(surfaces, flammables, heights, tips)

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CHEMICAL HAZARD

• H.R.Sarreshtahdar, MD
• Occupational Medicine Specialist

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Chemical hazards

• Chemicals are the most common and significant
  health hazards
• Chemicals can be hazardous for numerous reasons
  and can combine with other chemicals to make new
  hazards

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Toxicity

• Ability of the substance to harm the body
• The dose makes the poison
• Toxicity Depends on Amount Duration

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Hazardous Chemical Substances

• Entail a risk due to
• Its toxicological properties
• Its temperature
• Its radioactivity
• Displacement of atmospheric oxygen
• Increase the risk of fire, explosion,

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Classification

• Carcinogenic
• Irritant
• Corrosive
• Sensitizing
• Reproductive toxin
• Genotoxic
• Asphyxiants

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Carcinogenic

• IARC
• Group 1 (carcinogenic)
• Benzene, PAH, asbestos, silica
• Group 2A (probably carcinogenic)
• Acrylonytrile, vinyl chloride
• Group 2B (possibly carcinogenic)
• Acrylamide, lead, chloroform
• Group 3 (not classifiable)
• Group 4 (probably non-carcinogenic)

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Irritant

• Causes a REVERSIBLE inflammatory effect on
  living tissue by chemical action at the site of
  contact
• Formaldehyde, most solvents

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Corrosive

• Causes visible Destruction of or IRREVISBLE
  alterations in living tissue by chemical action
  at the site of contact
• Phenol, acids and bases

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Sensitizer

• Causes a substantial portion of exposed people to
  develop an Allergic reaction in normal tissue
  after repeated exposure to the chemical
• Nickel,

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Target Organ Classification

• Neuro-toxic
• Cardio-toxic
• Hepato-toxic
• Nephro-toxic
• Hemato-toxic
• Reproductive toxin

• Oculo-toxic
• Oto-toxic
• Pulmonary toxin
• Vasculo-toxic
• Dermato-toxic
• Immuno-toxic

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Physical Properties

• Aerosols
• Dust
• Fumes
• Smoke
• Fiber
• Gases and vapors
• Fluids

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Combined effects of chemicals

• Independent
• Additive
• Antagonistic
• Potentiating
• Synergistic

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Routes of Exposure Absorption

• Inhalation

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Routes of Exposure Absorption

• Skin/eye contacts

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Routes of Exposure Absorption

• Ingestion

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Particulate Sizing

• Inhalable Particle Mass
• Thoracic Particle Mass
• Respirable Particle Mass

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Factors affect toxicity

• Physical state
• Chemical structure
• Duration of exposure
• Frequency
• Route
• Intensity
• Environmental (temp/humidity/pressure)
• Individual factors
• race/genetics/immune/nutrition/activity/stress/
  background disease

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Monitoring

• Environmental monitoring
• Biological monitoring

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MSDS

• Prepared by the chemical manufacturer or importer
  and describe
• Physical hazards, such as fire and explosion
• Health hazards, such as signs of exposure
• Routes of exposure
• Precautions for safe handling and use
• Emergency and first-aid procedures
• Control measures

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MSDS

• Must provide information about the
• Physical and chemical characteristics
• Health effects
• Exposure limits
• Carcinogenicity (cancer-causing)

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Toxicity

• Information of the potential health hazards of
  chemicals is derived from...
• 1) Toxicological studies (in vivo, in vitro)
• 2) Case reports
• 3) Epidemiological studies

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Acute toxicity

• Acute oral, dermal or inhalation toxicity
• Provides information on acute health hazards
  likely to arise from acute exposure to the
  substance by the given route, and on the
  magnitude of acute toxicity of the substance
• usually these tests are made with rodents, dermal
  test quite often with rabbits
• LD50/LC50 values (dose level which is caused
  death to 50 of animals)

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Dose-response relationship lead
decreased erythrocyte delta-ALAD
activity increased zinc protoporphyrin
anemia
CNS effects
decreased peripheral nerve conductivity Nervous
paralysis, lead colics
Adapted from Elinder C-G et al., Biologisk
monitoring av metaller hos människa.
Arbetsmiljöfonden, Uppsala, 1991
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Some chemical hazards

• Metals
• Solvents
• Pesticides
• Gases
• Other chemicals

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Metals

• Lead
• Nickel
• Chrome
• Mercury
• Cadmium

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Solvents

• Aliphatic (methan, ethylene, )
• Aromatic (benzene, styrene, toluene,)
• Alcohols
• Petroleum distillates
• Ethers
• Esters

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Pesticides

• Organophosphates
• Carbamates
• Organochlorines
• Pyrethrum, pyrethroid

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Gases

• Asphyxiants
• Simple (CO2, methan, )
• Chemical (CO, H2S, HCN)
• Toxic gases (arsine, phosphine, phosgen,)