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Hazardous Waste Operations and Emergency Response

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Title: Hazardous Waste Operations and Emergency Response


1
Hazardous Waste Operations and Emergency Response
2
OSH Act
  • Applies to workplaces of more than 10 employees
  • Exempts farms, mines, and government agencies
  • Creates regulatory agency in Labor Dept OSH
    Administration
  • Creates research agency in HHS NIOSH

3
Responsibilities of OSHA
  • Establish safety and health standards
  • Conduct inspections
  • Require recordkeeping by employers and maintain
    national statistics
  • Conduct training

4
Introduction to HAZWOPER
  • HAZardous Waste OPerations and Emergency Response
  • Promulgated in 1989 (29 CFR 1910.120)
  • Developed in response to cleanup work resulting
    from CERCLA
  • SARA Title I required OSHA to develop standards
    for cleanup employees

5
Requirements
  • Health and Safety Plan (HASP)
  • Training
  • General site workers 40-hour 3-day on-site
  • Supervisors 40-hour 3-day on-site plus 8 hours
    specialized training in site-specific plans and
    programs
  • Limited access workers or safe sites 24-hour
    1-day on-site
  • All 8-hour annual refresher training

6
Training Involves...
  • Names of personnel and alternates responsible for
    site safety and health
  • Safety, health and other hazards present on the
    site
  • Use of personal protective equipment
  • Work practices by which the employee can minimize
    risks from hazards
  • Safe use of engineering controls and equipment on
    the site
  • Medical surveillance requirements, including
    recognition of symptoms and signs which might
    indicate overexposure to hazards and
  • The contents of paragraphs (G) through (J) of the
    site safety and health plan set forth in
    paragraph (b)(4)(ii) of this section.

7
Safety Procedures
  • Health and Safety Plan (HASP)
  • Site Control, including
  • A site map
  • site work zones
  • the use of a buddy system
  • site communications including alerting means for
    emergencies
  • the standard operating procedures or safe work
    practices and
  • identification of the nearest medical assistance

8
Setting Standards
  • Permissible Exposure Level (PEL) Standards
    initially drawn from ACGIH Threshold Limit Value
    (TLV) guidelines (1968 version)
  • Subsequent modifications typically from NIOSH
    through conventional rule-making protocol
  • Attempt to resynch with ACGIH failed

9
Whither the Standards?
  • Code of Federal Regulations (CFR) Title 29
    contain all OSHA regulations
  • Accessible on-line (though not necessarily with
    all tables and figures)
  • http//www.access.gpo.gov/nara/cfr/index.html

10
Hazard Communication
  • Established by OSHA in 1983
  • 29 CFR 1910.1200
  • Supports employees Right-to-Know

11
HazCom Program
  • Inventory of hazardous materials in plant
  • Material Safety Data Sheets (MSDS) available at
    all times
  • Labeling of containers and signage
  • Employee training program

12
MSDS
  • Identity
  • Hazard classification
  • Recommendations for usage
  • Emergency procedure guidance
  • Physical hazard data
  • Chemical hazard data
  • Physical and chemical properties
  • Manufacturer information

13
Chemical Toxins
  • All chemicals are toxic at some level
  • The dose makes the poison (paraphrasing
    Paracelsus ca. 1500)
  • Chemicals are in practice described as toxic if
    they cause harmful effects with modest exposures
  • EPA maintains Integrated Risk Information System
    (IRIS) http//www.epa.gov/iris

14
Classes of Toxicity
  • Acute vs. Chronic
  • Nature of effect
  • Systemic Poisons
  • Mutagens
  • Carcinogens
  • Teratogens
  • Behavioral Toxins

15
Systemic Poisons
  • Act upon the various cells of the body in such a
    way that performance is interrupted
  • The effect is usually not general, but manifested
    in one or more particular organs
  • Liver (hepatotoxin)
  • Kidney (nephrotoxin)
  • Nervous System (neurotoxin)
  • Cell necrosis is often the cause

16
Toxins Affecting DNA
  • Mutagens
  • Carcinogens

17
Mutagens
  • Damage the DNA
  • If cell divides before damage is repaired,
    resulting cells carry erroneous DNA without
    prospect of repair
  • Results run from cell necrosis up to the
    reproduction of dysfunctional cells
  • More serious effects with reproductive cells
    (eggs and sperm)

18
Carcinogens
  • Similar, and perhaps related to Mutagens (e.g.
    damage to genes regulating cell growth and
    division)
  • Associated with unrestrained growth and the
    tendency to metastasize
  • Benign tumors may become Malignant, i.e.
    cancerous
  • Often organ-specific

19
Reproductive Toxins
  • Teratogens
  • Toxins Affecting Fertility

20
Teratogens
  • Associated with fetal exposure to hazards
  • Cause abnormalities in offspring
  • Such effects hard to see above the background
    (perhaps as much as 10 of livebirths naturally
    show physical malformation and/or mental
    handicap)

21
Toxins Affecting Fertility
  • Systemic toxicity associated with male or female
    reproductive organ function (such as ovulation or
    sperm production)
  • Detected through epidemiological studies, which
    are difficult to validate because of social
    stigmas

22
Neurotoxins
  • Necrosis and tumor development are observable
    endpoints of some neurotoxins
  • Other dysfunction more difficult to detect
    because of chemical sensitivity of the brain and
    our general lack of knowledge of its function

23
E.g. methylmercury (CH3Hg)
  • 10 of body burden accumulates in brain
  • Crosses placenta and enters fetus (conc. in fetal
    red blood cells 30 higher than mom)
  • Symptoms
  • Numbness of extremities
  • Stumbling gait and difficult verbal articulation
  • Constricted visual fields and hearing
  • Muscle weakness, tremors, jerks ?coma/death

24
Risk Assessment Methodology
  • Typically decomposed into four steps
  • Hazard Identification
  • Dose-Response Assessment
  • Exposure Assessment
  • Risk Characterization

25
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26
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27
Hazard Identification
  • Determine the nature of the hazard
  • Exposure pathways of concern, e.g.
  • Ingestion
  • Inhalation
  • Dermal contact
  • Puncture
  • Toxic endpoints, e.g.
  • Lethal vs. non-lethal
  • Chronic vs. Acute

28
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29
Dose-Response Assessment
  • Relating Dose to (adverse) response
  • Response typically described as a probability
    (unitless fraction or percent)
  • Dose-Response Curve
  • Dose on the abscissa
  • Response on the ordinate
  • Intercept with abscissa is threshold dose

30
Measuring Toxicity
  • Need measures of dose which causes toxic endpoint
  • Measurements for ingested toxins ordinarily
    normalized for body weight (e.g. mg/kg)
  • Must generalize from populations of experimental
    subjects
  • For lethal endpoints can use LD50

31
But LD50 is limited!
32
e.g. here A is always more toxic than B
33
but A can be less toxic than C, even with lower
LD50
34
Acute Toxicity
  • Acute toxins result in observed endpoints after
    few exposures, in short timeframe
  • For lethal endpoints, toxicity is a measure of
    the amount of exposure required to produce death
  • Example endpoints chemical poisoning, radiation
    sickness

35
Chronic Toxicity
  • Chronic toxins produce observed endpoints only
    after repeated exposures and/or considerable
    elapsed time
  • Like acute toxicity, may be lethal or non-lethal
  • Toxicity may be cumulative or not (e.g. mercury
    vs. carbon monoxide)
  • Example endpoints cancer, birth defects

36
Toxicology vs. Epidemiology
  • Toxicology answers the wrong question well
  • Epidemiology answers the right question poorly

37
Toxicology
  • Controlled laboratory experimental conditions
  • but
  • Surrogate subjects (usually animals)
  • Exaggerated doses

38
Designing Toxicology Experiments
  • Selection of subject species
  • Control design
  • Multiple dose levels (at high levels to produce
    observable effect in relatively small number of
    subjects)

39
Epidemiology
  • Human subjects
  • Realistic doses
  • but
  • Uncontrolled experimental conditions

40
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41
Extrapolating High to Low Dose
  • Experimental studies produce minimum detectable
    responses on order of a percent
  • Desire information on order of 10-6
  • Its virtually impossible to perform lab studies
    with N large enough (e.g. megarat)
  • ? We need a mathematical model to perform
    extrapolation
  • Often plot log(Dose) to facilitate

42
Potency Factors(a.k.a. Slope Factors)
  • For chronic chemical toxicity (e.g. cancer),
  • Potency Factor ? slope of the low dose DR curve
  • where Chronic Daily Intake (CDI) is measured in
    units of mg/kg/day

43
Potency Factors (contd)
  • Re-arranging,
  • Incremental Lifetime Cancer Risk CDI ? PF
  • Potency Factors are available from EPAs
    Integrated Risk Information System (IRIS)
  • http//www.epa.gov/iris

44
Lifetime Exposure
  • where a 70-year lifetime is assumed

45
Example Chloroform in Drinking Water
  • Suppose your drinking water has 0.10 mg/L
    concentration of chloroform (CHCl3)
  • From IRIS, PF 6.1x10-3 (mg/kg/day)-1
  • So incremental lifetime cancer risk is

46
Chloroform Example (contd)
  • In a city of 500,000 people

47
General Exposure
48
Example Occupational Exposure
  • A 60 kg person works 5 days/week, 50 weeks/yr,
    for 25 years
  • Each workday they breath 20 m3 of air containing
    0.05 mg/m3 of toxin

49
Example (contd)
  • If the Potency Factor is 0.02 (mg/kg/day)-1

50
Non-carcinogenic Doses
  • Metrics from toxicity experiments include
  • Lowest Observed Effect Level (LOEL)
  • Lowest Observed Adverse Effect Level (LOAEL)
  • No Observed Effect Level (NOEL)
  • No Observed Adverse Effect Level (NOAEL)
  • Note NOEL and NOAEL are the highest experimental
    doses at which no (adverse) effect was seen

51
Reference Dose
  • The Reference Dose (RfD) is taken from the NOAEL
  • Where Uncertainty Factors are 10 each for
  • differences across population
  • using animal data to estimate human endpoints
  • using only a single species of animal

52
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53
Hazard Quotient
  • Compares exposure to Reference Dose
  • HQ lt 1 should be free if significant risk of
    toxicity

54
Hazard Index
  • Considers multiple risks (e.g. from multiple
    chemical toxins)
  • The sum of the Hazard Quotients
  • See Example 4.6

55
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56
Exposure Assessment
  • Risk has two components
  • Toxicity of the substance
  • Exposure of humans to substance
  • Exposure often forgotten (see, for example, the
    Scientific American article comparing indoor
    pollution to outdoor pollution)

57
Exposure Pathways
  • The route by which a toxin or hazard reaches the
    human influences its impact
  • Internal factors would include the human contact
    route (e.g. inhalation, ingestion, c)
  • External factors would include the physical
    transport (e.g. distance and travel time in air
    or water, c)

58
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59
Risk Characterization
  • Besides multiplying exposure by potency, consider
  • Statistical uncertainties
  • Biological uncertainties
  • Selection of applicable dose-response and
    exposure data
  • Selection of population groups toward which the
    risk assessment should be targeted

60
Occupational Standards TWA
  • The Time-Weighted Average (TWA) assumes an 8-hour
    day and 40-hour week

61
Exposure Routes and Effects
  • Principle routes for chemicals
  • Ingestion
  • Dermal
  • Inhalation
  • Other routes for hazard exposure
  • Puncture
  • Eyes
  • Ears

62
Gastrointestinal Exposures
  • Chemicals gain direct access to mucous membranes
    in stomach and intestines, allowing transfer of
    chemical to bloodstream
  • Digestive processes can transform chemicals into
    others
  • Physical hazard endpoints can apply (e.g. with
    ingested acids)

63
Dermal Exposure
  • Epidermis consists of former living cells
  • Removed from blood vessels to some extent
  • Acts as barrier to loss of fluids and entry of
    contaminants
  • Some materials are able to pass this barrier
  • Solvents which can be absorbed into the skin
  • Pores and hair follicles

64
Inhalation
  • Rapid route of entry to bloodstream
  • Alveoli designed to facilitate transfer of gases
    (oxygen and carbon dioxide)
  • Effectively transfer other materials too

65
Distribution of Toxicants
  • Two factors govern transport
  • Protein binding -
  • Toxicants can bind to proteins in the blood, thus
    preventing their access to surrounding cells
    through capillary walls
  • But access to kidneys (for removal) is also
    inhibited
  • Polarity -
  • Polar toxicants obstructed by non-polar membranes
  • Nonpolar toxicants dissolve through readily and
    can be stored in body fat

66
Metabolism
  • Conversion of materials through reaction
  • For toxicants, tendency is to increase
    polarization (and therefore reduce bio-uptake)
  • In some cases chemicals can be converted into
    more toxic materials

67
Pollution Control in the Body
  • Kidneys
  • Liver

68
Kidney Function
  • Blood flowing through kidneys is exposed to
    porous membrane
  • the (relatively) small molecules of toxins pass
  • substantial quantities of water also pass
  • Aqueous solution passes along tubes which
    selectively retrieve desirable nutrients, water
    c
  • Concentrated aqueous toxins expelled as urine

69
Liver Function
  • Metabolize toxicants into more polar structures
  • Some substances removed from blood and
    transformed into bile, stored in gall bladder
  • Gall bladder sends bile into small intestine to
    assist with digestion
  • Toxins therefore eliminated with feces (unless
    resorbed by intestinal walls)

70
Dermal Exposures
71
Anatomy of the Skin
  • Cutaneous Membrane
  • Largest organ of body (2500-3000 in2 in most
    adults)
  • Varying thickness (0.5 - 4 mm)
  • Diverse functions
  • Protection, excretion, sensation
  • Maintenance of fluid, electrolytes, temperature

72
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73
Epidermis
  • Outermost layer of skin
  • Cells migrate outward through this layer, in the
    process dying and becoming converted to the
    water-repellent protein keratin.
  • Inner (living) portion produces pigment (melanin)
    genetically driven to provide protection against
    electromagnetic radiation
  • Inner portion also produces new cells (mitosis)

74
Dermis
  • Inner layer of skin
  • Parallel ridges give rise to fingerprints
  • Provides structural integrity
  • Capillary blood supply provides plumbing to
    support the movement of materials in the skin
  • Blood vessels also act to permit temperature
    regulation through the skin

75
Pores and Hair Follicles
  • About 0.1 of skin surface area
  • Sebaceous glands secrete oil for the hair
    (prevents excess moisture movement)
  • Sweat glands (3000/in2 on the palms!) provide
    water to the skins surface to facilitate cooling
    through evaporation (and increased loss of
    keratin layer)
  • Hair follicles tunnel into dermis

76
Contact Dermatitis
  • Localized effect in response to chemical
  • Keratin layer is a barrier, except to corrosives
    and if physically compromised
  • Irritation results from inflammation and
    swelling, with sensory response
  • Cell death and damage to blood vessels can result

77
Irritant Contact Dermatitis
  • Chemical damage
  • Protected by oils and dead cells
  • Physical damage
  • Fibers, particulates can penetrate and abrade
    skin
  • Removal of oils and damage to keratin layer
  • Solvents
  • Soaps and detergents

78
Allergic Contact Dermatitis
  • Wide variation in response between workers
  • Sensitization permits increase in response with
    repeated contact
  • Results from immune system response to invasion
    of chemical-protein complexes produced when the
    chemical is absorbed into the skin

79
Photodermatitis
  • Results from photo-stimulated reaction of
    chemicals on the skin

80
Hair Problems
  • Hair loss
  • Death of cells at hair root
  • Chemical or radiation exposure
  • Color change
  • Most often caused by metals such as copper and
    cobalt
  • Has absolutely nothing to do with age ?

81
Acne
  • Result from blocked hair follicles trapping oils
    produced by the sebaceous glands
  • Can be exacerbated by temperature, chemical
    exposure, or physical stressors
  • Chloracne is similar but blockage results from
    damaged keratin rather than oil

82
Alteration of Skin Pigmentation
  • Phenolic compounds can interfere with melanin
    production
  • More severe cell damage can result in healing
    without regeneration of melanin producing cells

83
Corrosives
  • Produce acute and general tissue damage
  • Acids
  • Strong acids dissociate completely
  • Sometimes acid precursors react with water from
    or on skin
  • Bases
  • Strong bases (e.g. sodium hydroxide) equally
    damaging, and harder to remove

84
Cancer
  • UV light implicated in many skin cancers
  • Tar warts (some eventually becoming malignant)
    associated with polycyclic hydrocarbons
  • Similar evidence associated with chronic exposure
    to arsenic

85
Anatomy of the Eye
86
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87
Eye Hazards
  • Chemical Hazards
  • Corrosive vapors and splashes causing direct
    damage to eye is most important
  • Eye provides only a minor route of general
    systemic chemical exposure
  • Physical Hazards
  • Cuts and abrasions due to flying particles
  • Irritation due to particulate pollution
  • Optical damage (e.g. lasers)

88
Prevention of Irritation or Damage
  • Engineering Controls
  • Task re-design
  • Fume hoods, glove boxes, robots
  • Splash guards, enclosed pumps
  • Administrative Controls
  • Allergy screening prior to work assignment and
    monitoring for possible reassignment
  • On-going training regarding materials handling
    procedures

89
Prevention of Irritation or Damage (contd)
  • Personal Protective Equipment
  • Barrier creams
  • Protective clothing
  • Gloves
  • Safety glasses
  • Face shields

90
29CFR1910.133 (a)General
  • (1) The employer shall ensure that each affected
    employee uses appropriate eye or face protection
    when exposed to eye or face hazards from flying
    particles, molten metal, liquid chemicals, acids
    or caustic liquids, chemical gases or vapors, or
    potentially injurious light radiation.

91
29CFR1910.133 (a) General
  • (2) The employer shall ensure that each affected
    employee uses eye protection that provides side
    protection when there is a hazard from flying
    objects. Detachable side protectors (e.g. clip-on
    or slide-on side shields) meeting the pertinent
    requirements of this section are acceptable.

92
29CFR1910.133 (a) General
  • (3) The employer shall ensure that each affected
    employee who wears prescription lenses while
    engaged in operations that involve eye hazards
    wears eye protection that incorporates the
    prescription in its design, or wears eye
    protection that can be worn over the prescription
    lenses without disturbing the proper position of
    the prescription lenses or the protective lenses.

93
29CFR1910.133 (a) General
  • (4) Eye and face PPE shall be distinctly marked
    to facilitate identification of the manufacturer.

94
29CFR1910.133 (a) General
  • (5) The employer shall ensure that each affected
    employee uses equipment with filter lenses that
    have a shade number appropriate for the work
    being performed for protection from injurious
    light radiation. The following is a listing of
    appropriate shade numbers for various operations.

95
29CFR1910.133 (b) Criteria for protective eye
and face devices.
  • (1) Protective eye and face devices purchased
    after July 5, 1994 shall comply with ANSI
    Z87.1-1989, American National Standard Practice
    for Occupational and Educational Eye and Face
    Protection,'' which is incorporated by reference
    as specified in 1910.6, or shall be demonstrated
    by the employer to be equally effective.

96
29CFR1910.133 (b) Criteria for protective eye
and face devices.
  • (2) Eye and face protective devices purchased
    before July 5, 1994 shall comply with the ANSI
    USA standard for Occupational and Educational
    Eye and Face Protection,'' Z87.1-1968, which is
    incorporated by reference as specified in 1910.6,
    or shall be demonstrated by the employer to be
    equally effective.

97
Inhalation Exposures
98
Respiratory System
  • Nasal Cavity
  • Pharynx and Bronchial Tubes
  • Alveoli

99
Nasal Cavity
  • Mucous-lined passageway
  • Larger particles trapped in mucous
  • Sneezing reflex acts to expel particles
  • By-passed by mouth breathing under exertion,
    congestion, or habituation

100
Pharynx and Bronchial Tubes
  • Continuously subdividing branches
  • Increased cross-sectional area leads to decreased
    flow rate
  • Particles settle as flow rate decreases
  • Mucous migrates toward nasal cavity through
    motion of cilia

101
Alveoli
  • Small sacs (200 ?m diameter) at ends of bronchi
  • Tissue effects gas exchange with blood, O2 for
    CO2
  • Phagocytic cells escort particles out of alveolus
    if they can (but tobacco smoke inhibits this)

102
Atmospheric Contaminants
  • Particles
  • Gases or vapors

103
Specific Hazardous Particulates
  • Silica
  • Asbestos
  • Fiberglass
  • Coal Dust

104
Silica
  • SiO2
  • Silicosis from respirable particles (gt 5 ?m)
  • Toxic to phagogcytic cells
  • Enzymes resulting from digestion of dead cells
    leads to fibrosis (scarring of tissues)
  • Some concerns about juvenile exposure to play
    sand (especially fine sand sold for childrens
    sandboxes)

105
Asbestos
  • Fibrous minerals resistant to heat
  • Asbestosis is a fibrosis resulting from
    penetration of short (e.g. 1 ?m) fibers becoming
    embedded in respiratory passages
  • Irritation, edema, and scarring
  • Some varieties carcinogenic, and exacerbate
    effect of carcinogens in tobacco smoke

106
Fiberglass
  • Glass wool - thin fibers of glass
  • Used as insulation and fabrication material
  • Acts as irritant to lung tissue (as well as to
    epidermis)

107
Coal Dust
  • Black Lung disease
  • Dusts raised during mining operations settle in
    lungs
  • Fibrosis associated with other materials in mine
    atmosphere (e.g. silica)

108
Other Dusts
  • Dusts from cotton in textile manufacturing
    (brown lung disease)
  • Plastic dusts from circuit board manufacture
    (hole drilling for pin insertion)
  • Infectious dusts from poultry excrement (avian
    emphysema)

109
Hazards of Gases
  • Asphyxiants
  • Irritants

110
Asphyxiants
  • Reduce available oxygen supply
  • Brain most susceptible to diminished oxygen
    availability
  • Dilution - oxygen intake reduced due to lower
    concentration (in company of such gases as
    nitrogen, methane, or CO2)
  • Chemical inhibition (CO, hydrogen cyanide,
    hydrogen sulfide)

111
Irritants
  • Often acids or acid precursors
  • Upper and Lower respiratory tract categories
  • Upper RT usually more immediate, and therefore
    more likely worker would leave area
  • Lower RT often characterized by long time delay -
    worker may not react in time

112
Vapors
  • Many volatile compounds associated with toxic
    endpoints
  • Boiling point a major determining factor in
    degree of exposure
  • Odor or immediate irritation sometimes serves as
    warning
  • But many (such as phosgene) do not present such
    warnings until very toxic levels have been
    experienced

113
Occupational Asthma
  • Allergic inflammation of the lungs
  • Effects 3 of the population
  • Wheezing, coughing, shortness of breath in a
    worker may indicate an allergic response to a
    material in the workplace atmosphere

114
Industrial Air Quality Monitoring
115
Sampling Protocols
  • Grab vs. Integrated
  • Personal vs. Area

116
Grab Sampling
  • Measure the concentration of an airborne
    substance over a short time period (e.g. less
    than 5 minutes)
  • Effective as a screening technique to determine
    if more extensive monitoring is warranted
  • Not usually used to calculate TWA values, since
    sample times are rarely representative

117
Integrated Sampling
  • a.k.a. Continuous Sampling
  • Used to estimate 8-hour and 15-minute TWA
    exposures by collecting one or more samples over
    the duration of the task period
  • Integrates the various concentrations to which
    the worker has been exposed

118
Personal Sampling
  • Preferred method of evaluating worker exposure to
    airborne chemicals
  • Worker wears sampling device that collects sample
    wherever worker is, whatever theyre doing
  • Aperture should be as close as possible to
    breathing zone (hemisphere in front of the
    shoulders with radius of 6-9 inches)

119
Area Sampling
  • Evaluate background concentrations associated
    with a place (rather than with a worker)
  • Effective in investigating suspected leaks or
    hot spots
  • Not usually used to calculate TWA values, since
    the location is rarely representative of workers
    breathing zone

120
Collection Devices
  • Direct reading
  • Evacuated containers
  • Absorption
  • Adsorption
  • Filters
  • Passive vs. active

121
Direct Reading
  • Provide immediate indication of concentration
  • Example Colorimetric (stain) indicator tubes
    (Draeger tubes)
  • Electronic sensors available for some gases

122
Evacuated Containers
  • Reverse aerosol can
  • Plastic sampling bags

123
Absorption
  • Gas or vapor passed through absorbing liquid
    (e.g. acid vapors through deionized water)
  • Effective with reactive, soluble compounds
  • Absorption efficiency must be considered when
    calculating concentration in air from
    concentration in absorbent liquid

124
Adsorption
  • Alternative for insoluble or nonreactive gases
  • Solid sorbent (such as granular activated carbon
    or silica gel) provides sites to which
    contaminant molecules are attracted through van
    der Waals forces
  • Carbon adsorption tubes one of the most commonly
    used active collectors

125
Anatomy of an Adsorption Tube
  • Charcoal made from coconut shell large
    adsorptive surface area and nonpolar (so it
    prefers organic vapors rather than water c)
  • Standard tube 7cm long by 4 mm wide
  • 1st section contains 100 mg charcoal and a
    fiberglass, glass wool, or urethane foam plug
  • 2nd section (backup) contains 50 mg charcoal to
    detect breakthrough gt 10 back/front

126
Filters
  • Commonly used for particulates
  • Filter material chosen based upon analysis
  • Weight (total particulates within capture range)
  • Chemical composition (need material that
    dissolves or ashes to permit analysis)
  • Size categorization (translucence to permit
    microscopy for particle sizing and counting)

127
Passive vs. Active Monitoring
  • Passive monitors allow personal sampling without
    pumps
  • Rely on diffusion (movement across concentration
    gradient
  • Example Organic vapor monitor
  • Active monitors use pumps to move air through
    collection device

128
Analytical Methods
  • Sources of error
  • Determinate error (bias)
  • Indeterminate error (random)

129
On-site Analysis
  • Stain (indicator) tubes
  • Direct reading instruments

130
Laboratory Analysis
  • Gas Chromatography
  • Thermal Conductivity Detector
  • Flame Ionization Detector
  • Electron Capture Detector
  • Atomic Absorption
  • Spectrophotometry
  • IR, Visible, UV

131
Air Quality Controls
  • Engineering Controls
  • Administrative Controls
  • Personal Protective Equipment

132
Engineering Controls (Air)
  • Periodic maintenance of plumbing, valves,
    ducting, air-handlers, filters. c
  • Remote controls for chemical operations
  • Redesign of process to eliminate or reduce
    exposure-intensive steps
  • Substitution of less hazardous chemicals
  • Installation of effective ventilation system

133
Ventilation Terms
  • Air Pressure force of colliding air molecules
  • Static Pressure under influence of fan
  • Velocity Pressure inertia of molecules
  • Capture Velocity entrain mol. outside of duct
  • Transport Velocity entrain inside of duct
  • Flow rate volume/time

134
General Exhaust Ventilation
  • Exchange air in work room(s) with outside
    make-up air
  • Capacity described in room changes per hour
  • EQ/V
  • Intended to prevent contaminant concentration
    inside from rising to hazardous levels
  • Presumes outside air is cleaner than inside

135
Effect of GEV during generation
  • Change in mass as f(time,conc)
  • ?M G ?t - QC ?t
  • where G is generation rate (mg/min), C is
    concentration in exhaust air (mg/m3), and Q is
    flow rate
  • Divide by Volume to get ?C
  • ?C G ?t/V - QC ?t/V GenRate - RemRate
  • Burgess equation for conc as f(time)
  • C (G/Q)(1 - e-Qt/V)
  • Notice that for large t, Cmax ? G/Q

136
Effect of GEV after cut-off
  • Can be calculated as a decay process
  • Ct C0e-(Q/V)t
  • Setting Ct C0/2 we can calculate the half-life
    of the contaminant in the room
  • 1/2 e-(Q/V)t
  • ln(1/2) -(Q/V)t
  • t ln(1/2)/ (-Q/V) ln(1/2)(-V/Q)
  • t 0.693(V/Q)

137
Issues with GEV
  • Previous calculations assumed perfect mixing (?
    ideal transfer from room)
  • One room change ? all air exchanged
  • Exhaust system can bring contaminant into contact
    with more workers
  • Seasonal changes (e.g. heating/cooling) can alter
    performance of system

138
Local Exhaust Ventilation
  • Remove contaminant at its source
  • Assumes point sources
  • Lowers number of workers potentially exposed
  • But usually more susceptible to over-ride and
    undetected failure

139
Elements of LEV
  • Hood
  • Ducts
  • Treatment
  • Fan

140
Hoods
  • Aperture through which airborne contaminant is
    drawn into ventilation ducts
  • Capture Velocity is that velocity of airflow
    required to draw contaminant into hood
  • Velocity at distance x from hood
  • v kQ/(x2 kA)
  • where k depends on opening shape
  • and Q vhA

141
Types of Hoods
  • Capture
  • Canopy
  • Lateral
  • Push-pull
  • Enclosure
  • Receiving

142
Ducts
  • Duct performance is governed by resistance
  • Round ducts are less resistant than square
  • Why?
  • As (p/4)2 and Ac c2/(4?)
  • Setting As Ac, p 2c/ (?)1/2
  • p 1.128c
  • So for equal capacity, square has more surface
  • Resistance is proportional to velocity

143
Fan Issues
  • Noise
  • Maintenance

144
Treatment
  • Particulates
  • Settling Chambers
  • Baffles
  • Cyclones
  • Filters
  • Electrostatic Precipitators

145
Treatment
  • Vapor and Gas
  • Scrubbers
  • Adsorbents
  • Combustors

146
Administrative Controls
  • Reduced shifts in hazard area
  • Allergy and respiratory ailment screening
  • Employee health tracking

147
PPE Respirators
  • Air-purifying respirators
  • Filter mask (e.g. for dusts)
  • Adsorbent mask (e.g. for vapors)
  • Negative pressure
  • Atmosphere-supplying respirators
  • Self-Contained Breathing Apparatus (SCBA)
  • Supplied-Air Respirator (SAR)
  • Positive pressure

148
Respirator Issues
  • Masks must fit properly
  • Qualitative fit testing expose wearer to banana
    oil or saccharin mist and ask if they detect
  • Quantitative fit testing in chamber of known
    concentration, measure concentration inside
  • Workers must be trained (not all respirators are
    effective for all contaminants)
  • Workers must wear them to be protected

149
Fire
  • Combustion process requires Fuel and Oxidant,
    e.g.
  • CH4 2O2 ? 2H2O CO2
  • Flammability Limits lowest and highest
    concentration of fuel in air which will support
    continuous combustion
  • Depend on pressure, temperature, c

150
Explosion
  • Can be based on combustion
  • Wave of high pressure from rapid expansion
  • Could be mechanical (e.g. bursting vessel)
  • Explosives ? Chemicals combining both fuel and
    oxidant
  • Lower and Upper Explosion Limits (LEL and UEL)

151
Hazard Parameters
  • Volatility (vapor pressure and boiling point)
  • Flashpoint
  • Flammable vs. Combustible liquids (flash point
    below or above 100? F, respectively)
  • Autoignition temperature
  • Check out Table 9.1

152
Dust
  • Suspended particles of reactive materials can
    combust/explode like vapors and gases
  • Coal dust in mines and fiber dust in granaries
    are common examples
  • Particle surface area is an important variable

153
Combustion Products
  • CO2 and CO
  • Particulates
  • SO2 and H2S
  • Hydrogen Chloride and Phosgene
  • Hydrogen Cyanide
  • Metals

154
Prevention
  • Leak control
  • Temperature control
  • Ventilation
  • Fuel deprivation (e.g. housekeeping)
  • Spark suppression

155
Fire Control
  • Oxygen deprivation (e.g. CO2 and foam
    extinguishers)
  • Cooling to below ignition temperature (e.g. water
    extinguishers)
  • Training on use of extinguishers, and on
    evacuation and damage control techniques
  • Make sure available extinguishers match likely
    fire hazard (class A-D)

156
Fire Classification
  • Class A ordinary combustible materials (e.g.
    paper, wood, cloth, some rubber/plastic)
  • Class B flammable or combustible liquids, gases,
    greases, and some rubber/plastic
  • Class C energized electrical equipment
  • Class D combustible metals (e.g. sodium,
    magnesium, titanium, zirconium, lithium,
    potassium)

157
Medical Surveillance Program
  • All employees who are or may be exposed to
    hazardous substances or health hazards at or
    above the permissible exposure limits or, if
    there is no permissible exposure limit, above the
    published exposure levels for these substances,
    without regard to the use of respirators, for 30
    days or more a year
  • All employees who wear a respirator for 30 days
    or more a year or as required by 1910.134
  • All employees who are injured, become ill or
    develop signs or symptoms due to possible
    overexposure involving hazardous substances or
    health hazards from an emergency response or
    hazardous waste operation and
  • Members of HAZMAT teams

158
Medical Exams - when
  • Prior to assignment
  • At least once every twelve months for each
    employee covered unless the attending physician
    believes a longer interval (not greater than
    biennially) is appropriate
  • At termination of employment or reassignment to
    an area where the employee would not be covered
    if the employee has not had an examination within
    the last six months

159
Medical Exams - when (contd)
  • As soon as possible upon notification by an
    employee that the employee has developed signs or
    symptoms indicating possible overexposure to
    hazardous substances or health hazards, or that
    the employee has been injured or exposed above
    the permissible exposure limits or published
    exposure levels in an emergency situation
  • At more frequent times, if the examining
    physician determines that an increased frequency
    of examination is medically necessary.

160
Medical Exams - what
  • Medical examinations include
  • A medical and work history (or updated history if
    one is in the employee's file)
  • Special emphasis on symptoms related to the
    handling of hazardous substances and health
    hazards
  • Evaluate fitness for duty including the ability
    to wear any required PPE under conditions that
    may be expected at the work site.

161
HAZMAT Teams
  • First Responder
  • Awareness
  • Operations Level
  • Hazardous Materials
  • Technician
  • Specialist
  • Senior Emergency Response Official

162
Site Operations
  • Site Control
  • Roles and Responsibilities
  • Personal Protective Equipment

163
Site Control
  • Understand the site as best you can
  • Maps
  • roads
  • terrain
  • waterways
  • Engineering drawings
  • drains
  • storage areas
  • People
  • first hand knowledge

164
Site Work Zones
  • Exclusion Zone
  • The contaminated area
  • Contamination Reduction Zone (CRZ)
  • Area for decontamination
  • Support Zone
  • Uncontaminated area
  • Workers here NOT exposed to hazards

165
Boundaries
  • Hot line
  • Outer boundary of exclusion zone
  • Contamination Reduction Corridor
  • Passageway between Exclusion Zone and Support
    Zone
  • Decon done in this corridor
  • Contamination Control
  • Boundary between Support Zone and CRZ

166
Roles and Responsibilities
  • Responders (buddy system)
  • Backup (buddy system)
  • Decontamination
  • Research
  • Communications
  • Public Relations
  • Security
  • Site commander/manager
  • Medical
  • Site Safety

167
Personal Protective Equipment
  • Levels of protection A, B, C, or D
  • Chosen based upon nature of hazard

168
Level D
  • No respiratory protection
  • Limited skin protection
  • Must not exceed PELs, O2 gt 19.5
  • Typical
  • Disposable coveralls over work clothes
  • Work gloves
  • Chemical-resistant boots or shoes
  • Safety glasses/goggles
  • Hard hat

169
Level C
  • Limited respiratory and skin protection
  • When contaminants and concentrations known, and
    AP respirator can remove
  • Typical
  • Full-face air-purifying respirator
  • Chemical resistant clothing (e.g. bunny suit)
  • Inner and outer chem-resistant gloves
  • Chemical-resistant boots
  • Hard hat

170
Level B
  • Highest respiratory but limited skin protection
  • Minimum level for unknown sites
  • Only when dermal hazards unlikely
  • Typical
  • SCBA (pressure demand)
  • Chem resistant clothing (e.g. bunny suit)
  • Inner and outer chem-resistant gloves
  • Chemical-resistant boots
  • Hard hat

171
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172
Level A
  • Highest level of protection
  • When likelihood of dermal hazards
  • Typical
  • SCBA (pressure demand)
  • Fully-encapsulating, chem-resist suit
  • Disposal coveralls inside
  • Inner and outer chem-resistant gloves
  • Chemical-resistant boots
  • Hard hat

173
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174
Radiation
  • Electromagnetic radiation
  • Ionizing radiation
  • capable of separating molecules into cations and
    anions
  • e.g. X-rays
  • Non-ionizing radiation
  • doesnt normally disassociate molecules
  • e.g. radio frequency (RF) rays

175
Atomic reminders
  • Nucleus of an atom contains 1 or more protons,
    and 0 or more neutrons
  • Neutrons and protons have essentially equal mass,
    but proton has positive charge while neutron is
    electrically neutral
  • Elemental identity of an atom is determined by
    the number of protons (atomic number)

176
Atomic reminders (contd)
  • Common form of an element has a certain mass
    number protons neutrons
  • Other forms (isotopes) have the same number
    protons, but different numbers of neutrons
  • These are often unstable and prone to decay

177
Radioactive Decay
  • Unstable isotopes decay spontaneously, emitting
    various combinations of particles and energy
  • Some of these decay processes change either the
    isotope or the elemental identity of the atom
  • The rate of decay is characteristic of the
    starting isotope, and described by half-life

178
Decay Examples
  • 6C12 n ? 6C14 p
  • 92U238 ? 2He4 90Th234

179
Radioactive Half-life
  • Different nuclides (isotopes) distinguished by
    different decay constants (?)
  • Radioactive Half-life ? the length of time
    required for half of the atoms in the sample to
    decay
  • Decay is exponential Nt N0e-?t
  • So 0.5N0 N0e-?t, ? t1/2 -ln(0.5)/ ?

180
Types of Ionizing Radiation
  • Alpha
  • Nuclei of He atom (2 neutrons 2 protons)
  • Heavy (6.642x10-4g) and slow (104 miles/s)
  • Lots of interactions with energy transfer
    (30-100K ion pairs/cm air)
  • Travel only 1-8 cm in air, less in solids (like
    skin)
  • Most hazardous to humans from inside

181
Types of Ionizing Radiation
  • Beta
  • Electrons emitted from nucleus, charged (usually
    negative)
  • Light (9.130x10-28g) and fast (SOL 3x108m/s)
  • Fewer interactions (lt200 ion pairs/cm air)
  • Travel several meters in air, several cm through
    human skin
  • Can damage under skin, eyes

182
Types of Ionizing Radiation
  • Gamma
  • Electromagnetic ray (photon), neutral charge
  • Frequency characteristic of nuclide
  • Massless and fast (SOL)
  • Lower production of ion pairs than ? ?
  • Different penetration for different materials
  • 5 cm in lead
  • 50 cm in water
  • 50,000 cm in air

183
Types of Ionizing Radiation
  • X-Ray
  • Electromagnetic ray (photon), neutral charge
  • Frequency in X-ray portion of spectrum (generally
    lower energy than ?)
  • Massless and fast (SOL)
  • Lower production of ion pairs than ? ?
  • Penetration varies with energy

184
Types of Ionizing Radiation
  • Neutron
  • 1/4 mass of ?
  • Variable energy
  • Tissue penetration of 1-10 cm

185
Radiation Measurement
  • Geiger Counter
  • tube of readily ionized gas exposed to source
  • ions produced attracted to charged wire and
    produce electrical pulse
  • Scintillation Counter
  • Detector materials emit light when struck by
    radioactive emission
  • Photo tube detects light

186
Dosimeters
  • Theroluminescence Detector
  • Lithium fluoride exposed to radiation results in
    electrons raised to higher energy states (where
    they tend to remain for a period of time)
  • Relax with heat and measure emitted light
  • Film Badge
  • Photographic film develops with exposure
  • Assess degree of exposure of film as f(t)

187
Units
  • Rad (radiation absorbed dose)
  • A unit of dose (energy per unit exposed mass)
  • 1 rad 100 ergs/g 0.01 joules/g
  • Doesnt differentiate different types of
    radiation
  • Rem (Radiation Exposed Man)
  • Accounts for damage caused by exposure
  • rem rad QF
  • QF Quality Factor (10 for ?, 1-1.7 for ? ?)

188
Exposure Limits
  • Regulated by NRC (10 CFR)
  • Not to exceed 0.1 rem/yr excluding
  • background radiation
  • medical radiation (including voluntary
    participation in research studies)
  • Not to exceed 0.02 rem/hr (unrestricted)
  • Can apply for authorization up to 0.5 rem/yr
  • Demonstration of need

189
Health Effects
  • Long-term, low dose
  • Short-term, high dose

190
Thermal Stress
  • Issues relating to either lack of heat or
    excessive heat
  • Most emphasis placed on excess heat
  • Since humans are warm blooded, variations in our
    environmental temperature place significant
    burdens on the body

191
Thermal Zones
192
Master Equation
  • S (M W) R C K (Cresp Eresp) E
  • S heat storage rate
  • M metabolic rate
  • W external work rate
  • R radiant heat exchange rate
  • C convective heat exchange rate
  • K conductive heat exchange rate
  • Cresp rate of conv. heat exchange by respiration
  • Eresp rate of evap. heat lost by respiration
  • E rate of evaporative heat loss

193
Factors in Thermal Stress
  • Climatic conditions
  • Temperature, humidity, air movement
  • Work demands
  • Metabolic generation
  • Clothing
  • Insulation
  • Permeability
  • Ventilation

194
WBGT
  • Not a radio station
  • Wet Bulb Globe Temperature is an index combining
    three types of temperature measurement
  • TA Dry bulb thermometer (ordinary)
  • TNWB Natural Wet bulb thermometer (evaporative)
  • TG Thermometer in a black globe (radiant)

195
WBGT (contd)
  • Indoor
  • WBGT 0.7TWNB 0.3TG
  • Outdoor
  • WBGT 0.7TWNB 0.2TG 0.1TA

196
Standards
  • No OSHA PELs
  • ACGIH TLV
  • Matrix based on Work-Rest regimen and Work load
  • For continuous work
  • 30.0 C for Light Work Load
  • 26.7 C for Moderate Work Load
  • 25.0 C for Heavy Work Load

197
Health Implications of Heat
  • Heat Cramps
  • Muscle pain due to loss of fluids and salts
  • Heat Exhaustion
  • Loss of general blood pressure due to movement of
    blood to skin
  • Heat Stroke
  • Increase of body temperature (105F and up) with
    serious neurological endpoints

198
Health Implications of Cold
  • Frostbite
  • Skin tissue freezes, with damage due to expansion
    of water into ice
  • Hypothermia
  • General decrease in body temperature with
    neurological dysfunction
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