3140 finley road downers grove, il 60515 630.795.3200 1 fundamentals of industrial hygiene for...

1 3140 Finley Road Downers Grove, IL 60515 630.795.3200

Fundamentals of Industrial Hygiene

for Contractors and Technicians

Prepared by Clayton Group Services, Inc. – A Bureau Veritas Company

Downers Grove, IL 630.795.3200


INTRODUCTION • Basics of Industrial Hygiene• Anticipation

– Chemical and Physical Hazards– Heath Hazards and Routes of Entry

• Recognition– Identifying Potential Heath Hazards

• Evaluation– Measuring Exposure Concentrations

• Control– Exposure Control Concepts


INTRODUCTION

• Practice Session• Open Discussion


OBJECTIVES

• Understand the Field of IH• Understand the impact of chemical and physical

hazards on the short and long term health of workers

• Recognize and assess potential for excessive exposures

• Audit worksite for exposures


INDUSTRIAL HYGIENE

• The goal of an industrial hygiene program is to prevent employee exposures to hazardous substances.

• Plant health and safety personnel, industrial hygienists and contractors are the front line persons responsible for meeting this goal.

• Examples of health and safety programs that are critical to meeting this goal include: – Hazard Communication

– Hearing Conservation

– Respiratory Protection


INDUSTRIAL HYGIENE

• What is an Industrial Hygienist?

– Person having a degree in engineering, chemistry, physics, health physics, nursing, medicine, or related field, by virtue of special studies, training, experience, and/or certification has acquired competence in IH.


INDUSTRIAL HYGIENE

• Not everything hazardous on the job is a chemical.– Noise– Radiation– Vibration– Exposure to excessive heat or cold.

• Environmental Stressors– We will use this term to refer to both chemical and

physical agents.


INDUSTRIAL HYGIENE

• Many extremely harmful environmental stressors are used in industry without hazard because adequate precautions are taken to limit actual contact with them to amounts which will not cause injury or illness.


INDUSTRIAL HYGIENE

• Paracelsus, a Swiss-born physician, chemist and alchemist (1493-1541) once said:

– “All chemicals are poisons, there are none that are not. The difference between a cure and a poison is the dose”


TOXICITY VS. HAZARD

HazardHazardHazardHazardThe potential that a substance will cause an adverse effect in a given situation or environment.

The potential that a substance will cause an adverse effect in a given situation or environment.

It is important that one understand the distinction between toxicity and hazard.

ToxicityToxicityToxicityToxicityThe ability of a substance to produce an adverse effect in a biologic system(s).

The ability of a substance to produce an adverse effect in a biologic system(s).

Based on these definitions, two chemicals can have the same degree of toxicity, but present different degrees of hazard.


TOXICITY VS. HAZARD

• What is more toxic?– Mercury– Sodium chloride (table salt)

• What is more hazardous?– Putting a thermometer in your

mouth. – Ingesting 2 pounds of sodium

chloride


INDUSTRIAL HYGIENE

• When evaluating whether an environmental stress will be hazardous, it is necessary to know not only the toxicity, but also the physical and chemical properties, and the manner and quantity to be used.

• These factors help determine:– How much enters the body– Route of entry into the body– Frequency of exposure– Duration of exposure


HEALTH EFFECTS OF

ENVIRONMENTAL STRESSORS

HEALTH HAZARDS


HEALTH HAZARDS

• Common Types of Health Hazards – Carcinogens: capable of causing cancer

– Teratogens: capable of causing birth defects

– Mutagens: capable of producing genetic changes or damage

– Irritants: produces an irritating effect on contact with skin, eyes, nose and/or respiratory tract

– Corrosives: produces visible or permanent destruction of tissue at the site of contact

– Sensitizers: can cause an allergic reaction to the skin or respiratory track.

– Biological: living organism that can cause disease.


HEALTH HAZARDS

• Target Organ Effects - Chemicals that affect certain organs more than others

– Hepatotoxins - liver

– Nephrotoxins - kidney

– Neurotoxins - nerves

– Hematopoietic toxins - blood system

– Pulmonary toxins - lungs

– Skin toxins - skin


HEALTH HAZARDS

• For environmental stressors to cause harm they need to come into contact with the body

• Occupational Routes of Entry

– Inhalation

– Skin contact/skin absorption

– Ingestion

– Injection


HEALTH HAZARDS

• Inhalation - Lungs– Surface area of a tennis court– Enormous area for chemicals to exert their toxic effect– Gases and vapors pass through the lungs into the

blood, some more readily than others– Highly irritating chemicals, such as chlorine, will first

react with water in the upper airways– Less irritating chemicals will make it deep into the lungs

and get absorbed into the blood


HEALTH HAZARDS

• Nose: Large particles are trapped in mucus and hair. They are removed when you blow your nose.

• Air Tubes: Particles hit the walls of air tubes and are caught in mucus. Thin hair-like fibers beat and move the particles up the airways. They are then coughed out or swallowed.

• Air Sacs: Tiny dust particles are surrounded by special white blood cells which move them to where they can be coughed out or swallowed.


HEALTH HAZARDS

• Inhalation of Evaporated Chemicals

– Evaporation rate increases with rise in air and substance temperatures and an increase in wind and solar radiation since warmer air can hold more moisture.

– In general, organic liquids (benzene, gasoline) evaporate at lower temperatures and higher rates than water.


HEALTH HAZARDS

• Skin Contact

– Natural protective coating of oils acts as barrier to chemicals.

– Some chemicals, however, pass through the skin, are absorbed into the bloodstream, carried throughout the body, and can harm other organs.


HEALTH HAZARDS

• Skin Contact

– Benzene, carbon tetrachloride and methyl alcohol are easily absorbed.

– Substances will pass more readily through wet or damaged skin.

– You can also absorb chemicals through your eyes.


What skin hazard is present on almost every job?

HEALTH HAZARDS


Here Comes the Sun

• ABCDs of melanoma


HEALTH HAZARDS

• Ingestion

– Substances can enter the body through the mouth and digestive tract.

– Less common route of entry than respiratory or skin contact.

– Mouth contact with contaminated hands, food or cigarettes does occur.


HEALTH HAZARDS

• Injection– May inject chemical into your body by a needle

stick, laceration or puncture the skin on contaminated glass or a metal shard.


HEALTH HAZARDS

• Dose-Response Relationship

– How a chemical affects your body depends on how long you are exposed to it and the concentration (amount) of chemical exposure.

– Dose = Amount (concentration) x Time (duration)

– Response = Effect or reaction caused by dose


HEALTH HAZARDS

Allyl isothiocyanateAcetaldehydeAflatoxinAnilineBenzeneBenzo(a)pyreneCaffeic acidEthyl alcohol

Furan Furfural Heterocyclic aminesHydrazinesMethyl eugenolPsoralensQuercetin glycosides Safrole

What do these chemicals have in common?

Answer: They are all animal or human carcinogens or mutagens.


HEALTH HAZARDS

Remember that the “dose makes the poison.”

AppetizersCream of mushroom soup (hydrazines)

VegetablesBaked potato (ethyl alcohol, caffeic acid)Broccoli (allyl isothiocyanate)Celery (caffeic acid, furan derivatives, psoralens)

EntreesRoast Turkey (heterocyclic amines)Cranberry sauce (furan derivatives)

BreadRolls with butter (acetaldehyde, benzene, ethyl alcohol, benzo(a)pyrene,furan derivatives, furfural)

DessertApple Pie (acetaldehyde, caffeic acid, ethyl alchol, methyl eugenol, quercetin glycosides, safrole)

Holiday Menu


ACUTE HEALTH HAZARDS

• Acute Health Hazards - Happen soon after exposure, usually of short duration

– Irritant - reversible inflammation at the site of contact

• fiberglass insulation, ammonia, acid mists

– Corrosive - a visible destruction by chemical action

• Battery acid, some boiler water treatment chemicals



• The smaller amount of a substance it takes to produce the targeted effect, the more “toxic” the material.

• Rapid action, low dose• In pharmaceuticals this is

known as potency.



• OSHA defines a toxic agent as:

a. LD50 (oral) -- oral doses in rats ranging from 50 to 500

milligrams per kilogram (mg/kg)

b. LD50 (skin) -- 24-hour skin exposure to rabbits ranging from

200 to 1,000 mg/kg

c. LC50 -- 1-hour inhalation doses to rats ranging from 200 to

2,000 parts per million (ppm)

Examples: Ammonia, nitrogen dioxide, ethylene oxide



• OSHA Defines a highly toxic agent as:

a. LD50 (oral) -- oral doses in rats of less than 50mg/kg

b. LD50 (skin) -- 24-hour skin exposure to rabbits

of less than 200 mg/kg

c. LC50 -- 1-hour inhalation dose to rats of less

than 200 ppm

Examples: Hydrogen cyanide, mustard gas


CHRONIC HEALTH HAZARDS

• Chronic health hazards occur from long-term exposures - usually of long duration

– Sensitizers - allergies

– Carcinogens - cancers

– Target organ toxins


CHRONIC HEALTH HAZARDS

• Examples of chronic exposures and heath effects

– Smoking and lung cancer

– Sun exposure and skin cancer

– Alcohol and liver damage

– Benzene and leukemia

– Sugar and tooth decay


Let’s Discuss Exposure Limits


EXPOSURE LIMITS

• Exposure limits for many chemicals have been established.

• A chemical's exposure limit is the concentration of that chemical to which nearly all workers may be repeatedly exposed, day after day, without adverse health effects.


EXPOSURE LIMITS

• Exposure limits also for physical hazards

– Noise– Heat Stress– Cold Stress– Vibrations – Ionizing Radiation– Non-Ionizing Radiation


EXPOSURE LIMITS

• Exposure limits for chemicals are commonly expressed as:– parts per million (ppm) of a chemical allowed in the air,

or – milligrams per cubic meter of chemical allowed in the

air (mg/m3)

• Exposure above a chemical's exposure limit may produce harmful effects on the body.


Gas/Vapor

Aerosol

Aerosol

Fibers

ppm

mg/m3

mg/m3

Fibers

Formaldehyde, hydrochloric acid

Lead, cadmium (fume/dust)

Dusts

Asbestos, fiberglass

EXPOSURE LIMITS

Substance Unit Examples


EXPOSURE LIMITS

• To give you an idea of how little a ppm is:– 1 mile = 5280 feet – 1 ppm = 1/16 of an inch in a mile.


EXPOSURE LIMITS

• OSHA Permissible Exposure Limits (PELs) for chemicals are enforced by law.

• The American Conference of Governmental Industrial Hygienists (ACGIH) has set Threshold Limit Values (TLVs). – TLVs are voluntary exposure limits that

may be followed but are not enforceable by law.


EXPOSURE LIMITS

• PELs and TLVs are usually observed as time-weighted-average (TWA) concentrations for normal 8-hour workdays.

• In addition to the 8-hour TWA, some chemicals have exposure limits of 15 minutes called Short-Term Exposure Limits (STELs), and exposure limits that should never be exceeded for any amount of time, called Ceiling Limits (C).


EXPOSURE LIMITS

• Immediately Dangerous to Life and Health (IDLH) is the acute respiratory exposure that poses an immediate (within 30 minutes) threat to loss of life, immediate or delayed irreversible adverse effects on health, or acute eye exposure which would prevent escape from a hazardous atmosphere.


8–hr TWA 100 ppm

STEL 150 ppm

Ceiling 200 ppm

Zero ppm

0 1 2 3 4 5 6 7 8

HOURS

Peak 500 ppm

EXPOSURE LIMITS

Exposures are really the average concentration over the time sampled.


Back to the Field of Industrial Hygiene


The science and art devoted to the anticipation, recognition, evaluation, and control of those workplace stresses, environmental factors, or other hazards, which may cause sickness, impaired health and well-being, or significant discomfort among workers or among the community.

INDUSTRIAL HYGIENE

Industrial hygiene is. . .


INDUSTRIAL HYGIENE

There are four fundamental elements of industrial hygiene.

Anticipation Anticipation EvaluationEvaluation ControlControlRecognition

Each of these concepts will be further discussed throughout this presentation.


ANTICIPATION

Hazard anticipation is one of the proactive components of an industrial hygiene program.


• Review of chemicals (i.e., MSDSs)

• Review of chemical and physical properties

• Review of work practices and work conditions


RECOGNITION

Recognition of hazards relates to the identification of hazards and stressors in the workplace.


• Job Site surveys• Reviews of past accident reports, audit reports,

chemical inventories, etc. • Employee input


EVALUATION

Once a hazard has been anticipated and/or recognized, the degree of exposure to employees must be determined.


• Qualitative exposure evaluations

• Quantitative exposure monitoring


CONTROL

There are three primary controls that should be considered for eliminating hazardous exposures.


• Engineering Controls

• Administrative Controls

• PPE


ANTICIPATION

• Anticipation requires:

– Knowledge of the characteristics of the physical state of matter.

– Knowledge of the hazards of environmental stressors.

– Knowledge of how chemicals behave

– Knowledge of work practices and processes


ANTICIPATION

• Physical States of Matter – Solid– Liquid – Gas


ANTICIPATION

• Knowledge of the physical state of matter can help anticipate its movement in the air near the worker’s “Breathing Zone”.

• Breathing Zone

– Imaginary globe of two foot radius around the head where from which

a work breaths in air.


ANTICIPATION

• Physical State of Matter• Gases -

– Fills this space in which it is generated

– Can be toxic, flammable, explosive and/or corrosive

– Can be lighter than air

– Can be heavier than air Gas Model


ANTICIPATION

• Physical State of Matter• Vapors -

– Act like gases– Source is evaporated liquids

– Can be toxic, flammable, explosive and/or corrosive

– Don’t confuse vapors with “fumes”

– Can you identify a vapor generated at the worksite?


ANTICIPATION

• Gases and Vapors

– Vapor density (V.D.)- the weight of a vapor or gas compared to the weight of an equal volume of air.

– Can be lighter, heavier, or same density as air (air = 1)– Materials lighter than air will have vapor densities < 1.– Materials heavier than air will have vapor densities > 1.

• Vapor density of gasoline = 3 - 4 – Where would you expect the vapors to accumulate?

Q: What reference materials can you use to find the V.D. of a substance?


ANTICIPATION

• Vapor Density

• Hydrogen Gas = 0.07

• Air = 1.0

• Gasoline Vapor = 3.5

Rises

Sinks


ANTICIPATION

• Liquids

– Can evaporate to form toxic, corrosive and/or flammable vapors!


ANTICIPATION

• Inhalation of Evaporated Chemicals– Evaporation is the process in which a substance

changes from a liquid or solid phase to a gaseous or vapor phase.

– Some of the factors that affect evaporation include: air and substance temperatures,

• Wind Speed

• Solar Radiation

• Relative Humidity


• What can you “Anticipate", in general, what will happen to the vapors of liquid:

– On a hot, sunny day vs. a cold, cloudy day

ANTICIPATION


ANTICIPATION

• Solids

– Includes powders, smoke, mists, aerosols, fumes and dusts.

– Can be toxic and corrosive

– Can be combustible and flammable


ANTICIPATION

• If the product is solid, it may be crystalline, granular, powdery, etc. If the product is liquid, it may be viscous, gelatinous, oily, etc.


ANTICIPATION

• Dusts

– Behave like gases

– Smaller particles easily inhaled and stay airborne longer.

– Watch for ignition sources


ANTICIPATION

• Fumes – Source is molten or

vaporized metals– Smaller in size than dusts.

– There is no such thing as “paint fumes” or “gasoline fumes” but you can have “welding fumes”


ANTICIPATION

• Anticipation requires knowledge of the hazards of environmental stressors. – Chemical – Physical

• Knowledge of the chemical and physical hazards of matter can help anticipate how it will come into contact and/or interact with the body.


ANTICIPATION

• Chemical Hazards

– Corrosive– Irritant– Sensitizer– Toxic– Biohazards – Legionella

• Involves the health effect product from exposure to a liquid, gas or solid agent

• We covered this in the health hazard section


ANTICIPATION

• Physical Hazard of Chemicals – Radiation– Thermal– Ergonomic– Asphyxiant – Combustible– Flammable– Oxidizers

• May involve the release of energies under certain conditions

• May involve interaction with body systems


ANTICIPATION

• Radioactivity

– Source materials - substances that emit ionizing radiation (like plutonium)


ANTICIPATION

• Radioactive materials can be found in thickness gauges and casting inspection processes

• Radiation spills should only be approached by persons trained in radiation hazard recognition


ANTICIPATION

• Thermal Hazards

– Molten materials - hot, fire hazard, burns - “hot work”

– Cryogenic liquids (liquid oxygen, liquid nitrogen, etc.) - extremely cold, can displace air rapidly with uncontrolled release

– Heat Stress and Cold Stress covered later


ANTICIPATION

• Liquid nitrogen: – Cryogenic liquid-300 °F

– Can cause frostbite on contact

– Rapidly expands causing oxygen deficient atmosphere


ANTICIPATION

• Asphyxiant – Two kinds

• Simple and Chemical

– Simple Asphyxiant - displaces air, which contains the oxygen we need to live

• carbon dioxide, argon, nitrogen

– Chemical Asphyxiant - replaces oxygen in the blood - cells die from lack of oxygen

• carbon monoxide, methylene chloride


ANTICIPATION

• Flash Point – The flash point of a product is the lowest temperature

at which a sufficient amount of vapor is given off to create a mixture with the air which is flammable on contact with an open flame or spark.


ANTICIPATION

• Combustible Liquids

– “Flashpoint” of at least 100 0 F, but less than 2000 F

– DOT - flashpoint less than 1400 F

– Examples - diesel fuel, kerosene


ANTICIPATION

• Flammable Liquids

– Flashpoint less than 1000 F

– DOT definition less than 1400 F


ANTICIPATION

• Fire Triangle

– Need all three sides to have a fire

– Remove any one side - no fire occurs

– Chemical chain reaction - a fourth element?


ANTICIPATION

• Some flammable and combustible liquids chemicals at a worksite:

– Windshield Wiper Fluid (flash point = 54 °F)

– Gasoline(flash point = minus 45°F)

– Diesel fuel (flash point = 100 °F)

– No. 2 fuel oil (flash point = 136 °F)


ANTICIPATION

• Compressed gas cylinders are usually pressurized to 2,500 psi (or more).

• Damage to the neck, valves, or cylinder walls can result in a rupture and violent release of the gas.

• Cylinder can become a rocket.


ANTICIPATION

• Explosives - may be formed from mixtures of chemicals

• Oxidizers - chemically add oxygen, which accelerates certain chemical reactions - like fire (examples - oxygen, hydrogen peroxide)

• Pyrophoric Substances - ignites spontaneously in air at 1300F or less - like sodium

• Reactive Materials - release energy under conditions of shock, pressure or high temperature - like nitroglycerine


ANTICIPATION

• Water-reactive Chemicals

– Reacts with water to form toxic or reactive gases

– Example: calcium carbide and water creates acetylene gas (flammable and explosive)

– Acids and water generates heat and hydrogen gas


ANTICIPATION

• Chemical Compatibility

– When two or more chemicals can remain in contact indefinitely without reaction, they are compatible.

– Incompatibility may not always produce a hazard.


ANTICIPATION

• Incompatible chemicals can cause:– produce products more

hazardous than the original materials

– fires

– release hazardous energies

– Sodium hypochlorite (chlorine bleach) is incompatible with strong acids. On contact with them, it releases highly toxic chlorine vapors.


ANTICIPATION

• Preventing incompatible chemicals from contact with each other is key

• Store like materials together

• Consider:– Storage– Handling– Use Incompatible chemical storage


ANTICIPATION

• “Biohazards”– Includes bacteria, viruses,

parasites, insects and animal droppings

– Bloodborne Pathogens

• Exposure can result in disease transmission


ANTICIPATION

• Summary:– Anticipate whether a person may be exposed to an

environmental stressor based on your knowledge of how they behave and interact with the body and surrounding environment.


Nip it in the bud… Think

Ahead

ANTICIPATION


RECOGNITION

• Recognize the potential for worker exposure• Combine:

– Knowledge of the chemical and physical properties of chemicals.

• Heath effects• Physical state of matter• How chemicals behave

– Knowledge of the work practices and procedures.

• Exposure Assessment • Qualitative vs. Quantitative exposure evaluation


RECOGNITION

• What is Risk?

– Risk is the chance or possibility of an adverse outcome.

– We need to evaluate the risks to assess if a worker is potentially exposed to an environmental stressor over an occupational overexposure limit.


RECOGNITION

• Stressor Properties – “Exposure Limit”– Corrosive– Toxicity – Sensitizer – Irritant– Vapor Density– Physical State of Matter

• Risk Factors– Quantity Used– Length of Time Exposed– Type of Work Performed– Work Conditions– Ventilation– Use in Confined Spaces– History of Overexposure

Environmental Stressor Properties must be weighed against the Risks Factors

Exposure Assessment


RECOGNITION

• Stressor Properties• Ask yourself:

– Is there an exposure limit?

– If the answer is YES then continue.


RECOGNITION


– Is there an exposure limit?• If the answer is NO then your assessment is done (or is it?).• Other SAFETY RELATED hazards may exist but we are

focusing on overexposures to environmental stressors.

– Can you think of other SAFETY RELATED hazards?• Slip, trips, falls, etc


RECOGNITION


– If there is an exposure limit…. than I must assess whether the worker may be exposed over the limit using Risk Factors as a guideline.

• Qualitative Exposure Assessment


RECOGNITION

• Qualitative Exposure Assessment

– It is an educated guess on whether the worker will be exposed over the exposure limit or conservatively, ½ the exposure limit (action level).


RECOGNITION

• Risk Factors• Ask yourself:

– How much chemical will be used?– How long will they be exposed?– Will the type of work performed generate airborne

chemicals?– Will the work involve exposure to physical agents?– What is the physical state of the chemicals used or

generated?– Is there adequate ventilation?– Will the chemicals be use in Confined Spaces?


RECOGNITION


– How much chemical will be used?

• Total amount, surface area, etc.– The larger the surface area the more vapors are evaporated

• Quantity must be balance against hazardous nature of the material

• However: Small quantities of highly toxic or reactive substances can create significant risk.


RECOGNITION


– How long will they be exposed?

• The shorter the work process the less exposure duration.

• However: a short amount of exposure to a highly toxic or reactive substance can create significant risk.


RECOGNITION• Risk Factors• Ask yourself:

– Will the type of work performed generate airborne chemicals?

• Are gases used, generated or released?• Will a liquid generate vapors?• Will hot works generate fumes?• Will mechanical actions generate particles?

– If the process does not generate airborne agents then there will be no airborne exposure over an exposure limit.


RECOGNITION


– Will the work involve exposure to physical agents?• Noise• Radiation• Heat • Cold



– What is the physical state of the chemicals used or generated?

• Gas – Will be airborne

• Liquid– Can evaporate and release vapors

• Large particles (wood chips, granular salt)– Less likely to become airborne– Can contain small particles mixed in

• Small particles– Easily becomes airborne and inhaled


RECOGNITION


– Is there adequate ventilation?• Local Exhaust Ventilation (LEV)

– Can remove airborne agent at the generation source and greatly reduce the airborne concentration

• General Ventilation – Less effective than LEV– Can reduce airborne concentration by dilution



– Is there a history of personnel being overexposed during this work task?

• Look at OSHA Logs• Ask site safety personnel• Ask workers about past projects with air sampling• Is there a specific OSHA Regulation where you

assume overexposure until proven otherwise?– Lead– Asbestos– Others


RECOGNITION

• There are times that you can smell odors at concentrations many times lower than an exposure limit.


RECOGNITION

• Your sense of smell has capabilities and limitations:– Odor versus toxicity

• benzene – sweet, pleasant odor and carcinogen• skunk – brutal and irritant

– Olfactory fatigue• hydrogen sulfide – now you smell it… now you don’t

– Warning properties• mercaptans added to natural gas to give the

characteristic odor • carbon monoxide – no odor


Chemical Odor Low Odor High Description Irritating Conc.

Exposure Limit(ACGIH)

Acetone 20 ppm 679 ppm Minty Chemical, Sweet

200 ppm 500 ppm –8 hr750 ppm - STEL

Benzene 1.4 ppm 85 ppm Sweet, solvent 2,800 ppm 0.5 ppm – 8 hr2.5 ppm - STEL

Ethyl Benzene 2.0 ppm 200 ppm Aromatic 200 ppm 100 ppm – 8 hr125 ppm - STEL

Hydrogen Sulfide 0.0005 ppm 0.01 ppm Rotten eggs 10 ppm 5 ppm – 8 hr15 ppm - STEL

Perchloroethylene 4.6 ppm 69 ppm Chlorinated solvent 200 ppm 25 ppm – 8 hr100 ppm - STEL

Toluene 2.0 ppm 40 ppm Rubbery, mothballs 200 ppm 50 ppm – 8 hr

Xylene 0.08 ppm 40 ppm Sweet 100 ppm 100 ppm – 8 hr150 ppm - STEL

Selected Odor Thresholds

To be used as guidelines only.Are subjective and differ from person to person.

RECOGNITION


RECOGNITION

• Recognizing Symptoms of Exposure

– Review MSDS to identify sign and symptoms of overexposure.

– If your workers experience or report any of the listed signs and symptoms of overexposure they may be overexposed.


RECOGNITION

• Common Symptoms of Acute Exposure

– Feel dizzy while working with solvents

– Nose, lungs and eyes are irritated while working with particulates or corrosive chemicals

– Skin rash– Can you think of others?


• Does the material contain ingredients known to be toxic? At what concentrations?

• Does the ingredient have exposure limits?

• How will the material be used?

• Will employees be exposed to the material?

• What are the hazards of the material?

• What types of controls will be needed?

RECOGNITION

Summary: New materials and procedures should be reviewed prior to being introduced into the work environment.

MSDS


RECOGNITION

• Summary:– Your educated and experienced guess will help you to:

• Determine if an exposure over an occupational exposure limit is likely • If air sampling is required• If controls are necessary


EVALUATION

• Quantitative Exposure Assessment– Collecting actual

measurement of the environmental stressor of concern for comparison to occupational exposure limits.

– Must be conducted by an experienced Industrial Hygienist


• Determine the stressor that will be measured (i.e. a chemical, noise, biological hazard)

• Obtain the sampling and analytical method

• Design the sampling strategy

• Conduct the monitoring

• Analyze and interpret the results

• Determine recommendations for corrective actions based on results

• Document the monitoring results

EVALUATION

If qualitative evaluations are not sufficient, quantitative exposure monitoring may be necessary


Considerations include:

• The level of risk (i.e., the “worst first”)

• Regulatory requirements

• Signs or symptoms of exposure

• Employee requests for respirators

• History of high exposures

• New materials/process

EVALUATION

Since it is not possible to monitor everything at once, priorities need to be established.


EVALUATION

WHO: When selecting personnel to monitor, you should also look at “worst first.”

Maximum Risk EmployeeMaximum Risk EmployeeMaximum Risk EmployeeMaximum Risk Employee

The individual who is likely to have the highest exposureThe individual who is likely to have the highest exposure


EVALUATION

WHERE: When monitoring, a primary consideration is whether to collect Personal or

Area samples.

Personal SamplingPersonal SamplingPersonal SamplingPersonal Sampling Area SamplingArea SamplingArea SamplingArea Sampling

Air sampling of the contaminant concentration in the immediate work environment

Air sampling of the contaminant concentration in the immediate work environment

Air sampling of anindividual’s exposure

Air sampling of anindividual’s exposure


EVALUATION

WHEN: Sampling can be representative of a very short period of time or of a typical work day.

Air sampling representative of the typical workday

Air sampling representative of the typical workday

Air sampling representative of a very short period of time

Air sampling representative of a very short period of time

Grab SamplesGrab SamplesGrab SamplesGrab Samples Integrated Integrated SamplesSamples

Integrated Integrated SamplesSamples


EVALUATION

Direct Reading Direct Reading InstrumentsInstruments

Direct Reading Direct Reading InstrumentsInstruments

Oxygen MetersCombustible Gas Indicators

Colorimetric Tubes

Display concentration immediately Display concentration immediately

HOW: Will the sampling be collected?


EVALUATION

Active SamplersActive SamplersActive SamplersActive Samplers

Sampling Pump and Tubing

Collection Media

Require that a sampling “train” be establishedRequire that a sampling “train” be established



EVALUATION

Passive SamplersPassive SamplersPassive SamplersPassive Samplers

Canisters Badges

Do not require pump to move contaminant through collection mediaDo not require pump to move contaminant through collection media



• Demonstrate the relative safety of the operation.

• Demonstrate the effectiveness of controls.

• Reinforce effectiveness of safe work practices.

• Demonstrate company/regulatory compliance.

EVALUATION

Sampling results below established exposure limits may require no further action.


• Demonstrate the need for more effective engineering or PPE controls.

• Demonstrate the potential hazards of an operation.

• Reinforce the need for safe work practices.

EVALUATION

Sampling results above established exposure limits may indicate the need for corrective actions.


EVALUATION

The results of all exposure monitoring should be documented and communicated to affected persons.


EVALUATION

Direct-Reading Instruments

Multi-Gas Detector Combustible Gas Meter

Percent Oxygen

Carbon Monoxide

Hydrogen Sulfide


EVALUATION

Toxic, Explosive Atmospheres.

Risk of serious bodily injuries and death. You must fully understand how to use and calibrate the

meter before you attempt to use it.

Read the Operations and Maintenance Manual and practice using the instrument before an actual

emergency or project.

DANGER


EVALUATION

• Combustible Gas Meter

– Determines the concentration of flammable gases and vapors to assess the explosive potential and risk of working in that atmosphere (Quantitative Only)

– Meter typically reads in 0 - 100% of the lower explosive limit (LEL)

– Example: LEL for ethyl alcohol is 3.3%. If the meter reads 10%, then the concentration is 10% of 3.3% or .10 x 3.3 = 0.33%

• Or is it really 10% LEL? What is a correction factor?)


EVALUATION

• Explosive Atmospheres– EPA Action Guides for Unknown

Atmospheres:

• 0 - 10 % LEL Continue investigation• 10-25% LEL Continue with caution• > 25% LEL LEAVE AREA

IMMEDIATELY


EVALUATION

• Percent Oxygen in Atmosphere– Used to identify oxygen-deficient atmospheres– Meter reads out in percent oxygen, usually 0 - 25%– Calibrated to ambient oxygen (20.9%) concentrations in a clean

atmosphere

• EPA Action Levels– < 19.5% Supplied-air (SCBA) required– 19.5-25% Continue with caution– > 25% LEAVE AREA, INCREASED FIRE HAZARD


EVALUATION

• Carbon Monoxide– Colorless, odorless chemical asphyxiant – By-product of incomplete combustion

• Propane Forklifts– 8-hour TWA exposure limits

• PEL = 50 ppm• TLV = 25 ppm

– IDLH• 1200 ppm


EVALUATION

• Hydrogen Sulfide– Colorless gas with a strong odor of rotten eggs

– Often a by-product of decaying organic materials

– Often found in sewers; a confined space gas

– Exposure Limit - Ceiling

• OSHA = 20 ppm

• TLV = 10 ppm

• IDLH = 100 ppm


EVALUATION

• Detector Tubes – Direct-reading length of stain indicators– Can measure airborne concentrations of organic and

inorganic vapors and gases

• Ethyl alcohol• Hydrochloric acid• Hydrogen peroxide


EVALUATION

• Process Analyzers - HNU• In 1974, the first commercial

photoionization instrument (PID) was introduced by HNU Systems, Inc


EVALUATION

• PID– To determine the relative concentrations of air

contaminants specifically calibrated for the instrument– Will not measure:

• Dust• Fumes• Solids of any kinds

– Strictly quantitative and not qualitative• How much but not exactly what it is

– High humidity reduces sensitivity


CONTROLS

• Sound Insulation• Ventilation• Isolation

Engineering Engineering ControlsControls

• Job rotation• Change work practices• Material substitution

Administrative Administrative ControlsControls

• Eye, face, hand, body, head, foot protection

• Respiratory protection

Personal Personal Protective Protective EquipmentEquipment


CONTROLS

Engineering controls remove or isolate the hazard.

• Design and redesign• Substitution• Isolation• Enclosure• Ventilation


CONTROLS

Administrative controls include the work rules and procedures that help minimize exposures.

• Written programs• Standard operating

procedures• Training• Limited exposure time• Job rotation• Medical surveillance

Procedures


CONTROLS

PPE provides a physical barrier between the hazard and the employee.

• Eye and face protection• Hearing protection• Hand and body protection• Head protection• Respiratory

protection


CONTROLS

Other controls to reduce the risk of exposure include:

• Good housekeeping• Preventive maintenance• Continuous monitoring devices

and alarms• No eating or drinking at the

worksite.• Personal hygiene


SUMMARY

• Why do we need to understand Environmental Stressor?

– The physical and chemical properties of hazardous materials can predict how they will behave in the environment

– How they behave will assist in predicting the potential for a worker exposure situation.

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