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									Chemical Hazard Communication

        Chemistry 550
Be a Scout: Be Prepared
Chemical Risk Assessment

               Process
•   Identify chemical-using activities
•   Identify chemicals
•   Gather hazard information
•   Evaluate hazards and appropriate
    controls relative to usage
  Chemical Risk Assessment
Identify Chemical-Using Activities
       Chemical Risk Assessment
              Identify Chemicals
• Chemical Inventory:
  Required by CHP
  Used for compliance with other regulations
  Source of info during emergency response
  Identify specific safety & health concerns
  (monitoring for exposure, time-sensitives)
  Useful for finding small amounts of a material
  (waste reduction)
    Chemical Risk Assessment
Gather Hazard Information: Sources
• Merck Index: chemical structure, CAS#,
  technical references, physical data
• Sax: chemical formula, toxicity data,
  safety
• Hawley’s Condensed Chemical
  Dictionary: physical properties, chemical
  formula, hazards, uses
• Material Safety Data Sheet (MSDS)
            Hazard Evaluation
            What is my risk?
• Factors:
  Specific activity: heating, increased pressure?
  Type and amount used
  Duration & frequency of usage
  Controls used: engineering, administrative, PPE
• Written SOPs have to be thorough and be
  followed by everybody
• Always be looking for a safer way!
        Material Safety Data Sheet:
       A Key Hazard Evaluation Tool
• Probably the best “one-stop”
  source for information of all
  aspects of chemicals.
• Hard copy, vendor-specific
  for every chemical used –
  use EH&S website to locate
• No good unless they are used and interpreted relative to
  use.
• Nuances
                MSDS
               Chemical Identity
                 Physical Data
          Physical & Health Hazards
       Signs & Symptoms of Exposure
         Permissible Exposure Limits
Procedures for safe handling and use (e.g., PPE,
      engineering controls, storage, spills)
               Control Measures
           Emergency and First Aid
             Contact Information
         Hazard Assessment
    2 Major Classification Schemes
Physical Hazards:
flammable/combustible
liquids, compressed
gases, explosives,
organic peroxides,
oxidizers, pyrophorics,
unstables, water
reactives.
     14

                                                       Bleach
     12
                                  Aqueous ammonia
     10                        Milk of magnesia
                                                 Borax
                    Baking soda solution
     8
                                             Sea water
pH




                                  Blood
                                          Pure Water
                           Milk
     6
                               Black coffee
     4       Tomatoes
                        Wine
          Vinegar
     2              Lemon juice
              Stomach fluids
           Battery acid
     0
       100     10-2    10-4   10-6   10-8    10-10 10-12 10-14
     Proton or hydronium ion concentration [H3O+] in moles per liter
        Flashpoint
• The minimum temperature at which a
  liquid gives off a vapor in sufficient
  concentration to ignite under specific
  test conditions.
• Examples:
  – gasoline, - 45oF
  – mineral spirits, 102oF to 110oF
                Vapor Pressure
• Pressure exerted by a saturated vapor above
  its own liquid in a closed container.
• Expressed as pounds per square inch (psig
  or psia), or millimeters of mercury (mmHg).
• Vapor pressure increases with temperature
• 1atm = 760mmHg = 29.92”Hg = 14.7psi
• The lower the boiling point of a substance,
  the higher its vapor pressure
         Table 5. Vapor pressure of select compounds*


                    Material      Vapor pressure (mm Hg)

      parathion (insecticide)     0.00004
             sulfuric acid        0.001
                                                Slow evaporation
         elemental mercury        0.0012
             mineral oil mist     < 0.5
                   kerosene       5.0
                     octane       10.0          Moderate evaporation
                       water      18.6
                    gasoline      38 - 100      Fast evaporation
                    chlorine      5,200         Gas at standard conditions
* at standard (room) temperature and pressure
            Evaporation Rate
• FAST evaporating if greater than 3.0.
  – Examples: Acetone = 5.6, Hexane = 8.3.

• MEDIUM evaporating if 0.8 to 3.0.
  – Example: 190 proof Ethyl Alcohol = 1.4.

• SLOW evaporating if less than 0.8.
  – Examples: Water = 0.3, Mineral Spirits = 0.1.
   Stability and Reactivity Data
• Incompatibilities – important for usage and
  storage
• Water – important in fire-fighting situations
• Heat – relationship with pressure/volume
• Oxidizers – non-flammable but make
  combustion possible or faster
               Physical Hazards
                 Flammables
• Definitions: flammables/
  combustibles
• Eliminate ignition sources
• 10 gallon/40 liter limit
• Store away from oxidizers or
  other incompatibles
• Use approved refrigerators
• Make sure fire extinguishers
  are available
                Physical Hazards
                   Reactives

• Explosives, pyrophorics,
  oxidizers, air/water
  reactives
• Peroxide-formers: date
  containers; test opened
  containers every six months;
  test unopened containers
  prior to expiration date.
     Hazard Assessment
2 Major Classification Schemes


 Health Hazards: carcinogens,
 corrosives, toxics/highly toxics,
 reproductive toxins, irritants,
 sensitizers, target organs
Acute & Chronic Health Effects

• Acute – immediate, short duration; examples:
  nausea, dizziness, headache, irritation
• Chronic – long term; carcinogenicity, asbestosis
• Signs & symptoms of overexposure
        Dose-Response Curve
• Fundamental tenet of toxicology
• Key concept to understand for the assessment of
  health hazards.
• “As the dose increases, so does the response”
• What kinds of responses? (signs & symptoms of
  exposure)
• Benefits versus risks of chemical exposure -
  pharmaceuticals
                Health Hazards
              Toxic/Highly Toxic

LD50 (milligrams toxin per
kilogram of body weight). A
lower LD50 value means that
it is more harmful (toxic).
LC50 (milligrams toxin per
cubic meter of air or in parts
per million). A lower LC50
value means that is more
harmful (toxic).
Table 3. Probable Lethal Dose for Humans

Toxicity                  Animal LD50               Lethal Dose When Ingested
Rating                    (per kg)                  by 70-kg (150lb) Human

extremely toxic           <5mg                      less than 7 drops

highly toxic              5-50mg                    7 drops to 1 teaspoonful

moderately toxic          50-500mg                  1 teaspoonful to 1 ounce

slightly toxic            500-5,000mg               1 ounce to 1 pint

practically nontoxic      above 5,000mg             above 1 pint


Source: Prudent Practices in the Laboratory, 1995
Table 4. Lethal dose and lethal concentration examples

Compound               Animal   Route        LD50/LC50


Ethanol                Rat      Inhalation   20,000ppm
Ascorbic Acid          Rat      Oral         11,900mg/kg
Acetone                Rat      Oral          5,800mg/kg
Acetic Acid            Rat      Oral          3,310mg/kg
Aspirin                Rat      Injection     1,450mg/kg
Formaldehyde           Rat      Oral           800mg/kg
Atrazine (herbicide)   Rat      Oral           672mg/kg
Phenol                 Rat      Oral           317mg/kg
                Health Hazards
                 Carcinogens
• Cause cancer
• Designated area
• Require prior approval
  along with materials
  that are reproductive
  toxins
• Make sure signs are in
  place
              Health Hazards
            Corrosives / Irritants
• Wear appropriate PPE that
  protects eyes and exposed
  skin – know where
  emergency equipment is
  located.
• Always add acid to water
• Have calcium gluconate gel
  available when working with
  HF
• Distinction with “irritants”.
                Health Hazards
                  Sensitizer

• Repeated contact with
  material causes
  heightened response
• Metals, aldehydes
                Health Hazards
              Target Organ Effects
• Hepatotoxins – liver; carbon tetrachloride
• Nephrotoxins – kidneys; halogenated
  hydrocarbons
• Neurotoxins – nerve; mercury
• Hematopoietic – blood; CO
• Pulmonary – lungs; asbestos
• Reproductive (including teratogens)
  – embryo or fetus; DBCP
• Cutaneous – skin; ketones
• Eye - acids
                Exposure Limits
 Maximum levels considered safe for most people when exposed
 8 hr/day, 40 hrs/wk, 50 wks/yr, over a lifetime
TWAs
• PEL – OSHA
  (Law)
• REL – NIOSH
  (Guide)
• TLV – ACGIH                           Other designations
  (Guide)
                                        • STEL
                                        • Ceiling (C)
                                        • "Skin"
                                        • IDLH
Conducting a Chemical Hazard
         Evaluation.

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