TOPIC : DIFFERENT TYPES OF TOPIC : DIFFERENT TYPES OF HAZARDSHAZARDS

DATE : 10 AUGUST 2010, DATE : 10 AUGUST 2010, WEDNESDAYWEDNESDAY

LECTURE 7.4 : LECTURE 7.4 : INDUSTRIAL HYGIENEINDUSTRIAL HYGIENE

Health, Safety & Environment (CBB 2012)

Contents and OutcomesContents and Outcomes

• Able toAble to– Define Industrial hygiene & scope of IHDefine Industrial hygiene & scope of IH– Quote the relevant OSH regulationsQuote the relevant OSH regulations– Describe hazards of toxic materials, dose-Describe hazards of toxic materials, dose-

response relationship and define different response relationship and define different types exposure/measurementtypes exposure/measurement

– Identify entry of routes for toxic material Identify entry of routes for toxic material – Define sick-building syndrome and confined Define sick-building syndrome and confined

spacespace

What is Industrial Hygiene?What is Industrial Hygiene?

• Industrial Hygiene – Industrial Industrial Hygiene – Industrial safety safety and health specialtyand health specialty

• Concerned with predicting, recognising, Concerned with predicting, recognising, assessing, controlling, and preventing assessing, controlling, and preventing environmental stressorsenvironmental stressors in the in the workplace that can cause sickness or workplace that can cause sickness or serious discomfort to workers.serious discomfort to workers.

Environmental StressorsEnvironmental Stressors• An environmental stressor is any factor in the An environmental stressor is any factor in the

workplace that can cause enough discomfort to workplace that can cause enough discomfort to result in lost time or illness. Examples:result in lost time or illness. Examples:– Hazardous Substances:Hazardous Substances: gases, fumes, vapors, dusts, gases, fumes, vapors, dusts,

oxidizers, acids, caustics, etc.oxidizers, acids, caustics, etc.

– Harmful Physical AgentsHarmful Physical Agents hazards such as noise, hazards such as noise, vibration, temperature, radiationvibration, temperature, radiation

– Infectious AgentsInfectious Agents hazards such as TB, HIV, HBV, and hazards such as TB, HIV, HBV, and other diseases carried in bodily fluids.other diseases carried in bodily fluids.

– ErgonomicErgonomic hazards hazards

– OthersOthers: mold, fungus, animal feces, bugs: mold, fungus, animal feces, bugs

IH Scope - AssessmentIH Scope - Assessment

• Identify potential exposure hazardous Identify potential exposure hazardous substancessubstances

– Labels or MSDSLabels or MSDS

– Process design, ventilation, altered Process design, ventilation, altered chemicals, migrant vapors/fumes/dustchemicals, migrant vapors/fumes/dust

– Spot test – dosimeter tubes, monitoring Spot test – dosimeter tubes, monitoring equipmentequipment

IH Scope - Control/Prevention IH Scope - Control/Prevention StrategiesStrategies

• Eliminate: isolation/ventilation or Eliminate: isolation/ventilation or replacement of hazardous substancereplacement of hazardous substance

• Guard: ventilation/dilution, PPE, rotate Guard: ventilation/dilution, PPE, rotate employeesemployees

• Training: task, method, avoidanceTraining: task, method, avoidance

• Warning: MSDS, signage, chemical labelsWarning: MSDS, signage, chemical labels

IH Scope - MonitoringIH Scope - Monitoring

• Plan for “greatest” or “representative” Plan for “greatest” or “representative” personal sample by personal sample by individual/job/task/timeindividual/job/task/time

• Take multiple (short) samples to ensure Take multiple (short) samples to ensure quality of monitoring (look for “spikes”)quality of monitoring (look for “spikes”)

• Take ambient measures to support Take ambient measures to support personal resultspersonal results

• Get samples analyzed, calculate exposureGet samples analyzed, calculate exposure

Related RegulationsRelated Regulations

• Occupational Safety and Health Occupational Safety and Health (Classification, Packaging and Labelling of (Classification, Packaging and Labelling of Hazardous Chemicals) Regulations 1997Hazardous Chemicals) Regulations 1997

• Occupational Safety and Health (Use and Occupational Safety and Health (Use and Standards of Exposure of Chemicals Standards of Exposure of Chemicals Hazardous to Health) Regulations 2000Hazardous to Health) Regulations 2000

Occupational Safety and Health Occupational Safety and Health (Classification, Packaging and Labelling (Classification, Packaging and Labelling of Hazardous Chemicals) Regulations of Hazardous Chemicals) Regulations

19971997

• Classification - supplier’s responsibility to Classification - supplier’s responsibility to classify hazardous chemicals according to classify hazardous chemicals according to the specific nature of the risk involved.the specific nature of the risk involved.

• Packaging - safe packaging (material, Packaging - safe packaging (material, fastening and seal)fastening and seal)

• Labelling - clear (name of chemical, Labelling - clear (name of chemical, supplier and symbol)supplier and symbol)

SymbolsSymbols

Occupational Safety and Health (Use and Occupational Safety and Health (Use and Standards of Exposure of Chemicals Standards of Exposure of Chemicals

Hazardous to Health) Regulations 2000Hazardous to Health) Regulations 2000

• Employer identify and record all chemicals Employer identify and record all chemicals hazardous to healthhazardous to health

• Employer shall ensure that the exposure is Employer shall ensure that the exposure is within limitwithin limit

• Employer is responsible to prepare a Employer is responsible to prepare a exposure control action planexposure control action plan

• Labelling, training, health surveillance, Labelling, training, health surveillance, medical and warning signsmedical and warning signs

Chemical Hazards - Material Safety Chemical Hazards - Material Safety Data SheetsData Sheets

MSDS - special sheets that summarise all pertinent MSDS - special sheets that summarise all pertinent information about a specific chemical. information about a specific chemical. Designed to Designed to provideprovide workers and emergency personnel with workers and emergency personnel with the the proper procedures for handling or workingproper procedures for handling or working with a with a particular substanceparticular substance

–Manufacturer's name, address, and telephone numberManufacturer's name, address, and telephone number–List of hazardous ingredientsList of hazardous ingredients–Physical/chemical characteristicsPhysical/chemical characteristics–Fire and explosion hazard informationFire and explosion hazard information–Reactivity informationReactivity information–Health hazard communicationHealth hazard communication–Safety precautions for handlingSafety precautions for handling–Recommended control proceduresRecommended control procedures

Material Safety Data SheetsMaterial Safety Data SheetsMSDS must contain specific information inMSDS must contain specific information in eighteight categoriescategories::

Section I: Section I: General informationGeneral informationSection II: Section II: Hazardous ingredientsHazardous ingredientsSection III: Section III: Physical and chemical Physical and chemical

characteristicscharacteristicsSection IV: Section IV: Fire and explosive hazard dataFire and explosive hazard dataSection V: Section V: Reactivity dataReactivity dataSection VI: Section VI: Health hazardsHealth hazardsSection VII: Section VII: Safe handling and useSafe handling and useSection VIII: Control measuresSection VIII: Control measures

Toxic MaterialsToxic Materials

People are exposed to a variety of substances People are exposed to a variety of substances every day in the home and at work - paints, every day in the home and at work - paints, paint remover, detergent, cleaning solvents, paint remover, detergent, cleaning solvents, antifreeze, and motor oil. antifreeze, and motor oil.

Many of the substances we interact with are not Many of the substances we interact with are not dangerous in small quantities or limited dangerous in small quantities or limited amounts.amounts.

Hazards of Toxic MaterialsHazards of Toxic Materials

A toxic substance is one that has a negative A toxic substance is one that has a negative effect on the health of a person or animal. effect on the health of a person or animal. Toxic effects are a function of several factors:Toxic effects are a function of several factors:

• properties of the substanceproperties of the substance

• amount of the doseamount of the dose

• level of exposurelevel of exposure

• route of entryroute of entry

• resistance oresistance off the individual to the the individual to the substancesubstance

Relationship of Doses and Relationship of Doses and ResponseResponse

• A major goal of health and safety research, and A major goal of health and safety research, and industrial hygiene is to understand the relationship industrial hygiene is to understand the relationship between the dose of a substance and the human between the dose of a substance and the human responseresponse– Dose - can be amount per unit body weight (g/kg)Dose - can be amount per unit body weight (g/kg)– Dose threshold - minimum dose to produce a Dose threshold - minimum dose to produce a

measurable effectmeasurable effect– Lethal dose (LD) - a dose that is highly likely to cause Lethal dose (LD) - a dose that is highly likely to cause

deathdeath– Lethal concentration (LC) - inhaled concentration is Lethal concentration (LC) - inhaled concentration is

very likely to cause deathvery likely to cause death

Level of Exposure (Measurement of Level of Exposure (Measurement of Toxicity)Toxicity)

Setting a standard level of effect is difficult since Setting a standard level of effect is difficult since people vary in sensitivity.people vary in sensitivity.

• Exposure Ceiling – concentration level of a given Exposure Ceiling – concentration level of a given substance that should not be exceeded at any substance that should not be exceeded at any point during an exposure periodpoint during an exposure period

• Emergency Exposure Limit (EEL): approximate Emergency Exposure Limit (EEL): approximate length of time a person might remain without ill length of time a person might remain without ill effect in an atmosphere contaminated with specific effect in an atmosphere contaminated with specific concentration of toxic gases. concentration of toxic gases.

• Threshold Limit Values (TLVs): average concentration Threshold Limit Values (TLVs): average concentration of toxic agents that can be tolerated during exposure of toxic agents that can be tolerated during exposure for a 40-hour weekfor a 40-hour week

• Time Weighted Average (TWA): average concentration Time Weighted Average (TWA): average concentration of substance to which employees may be safely of substance to which employees may be safely exposed over an 8 hr workday or a 40 hr work weekexposed over an 8 hr workday or a 40 hr work week

• Short-term Exposure Limit (STL): maximum Short-term Exposure Limit (STL): maximum concentration of substance to which employees may concentration of substance to which employees may be safely exposed for up to 15 minutes without be safely exposed for up to 15 minutes without suffering irritation, chronic or irreversible tissue changesuffering irritation, chronic or irreversible tissue change

Level of Exposure (Measurement of Level of Exposure (Measurement of Toxicity)Toxicity)

Entry Points for Toxic AgentsEntry Points for Toxic Agents

InhalationInhalation

Skin absorptionSkin absorption

InjectionInjection

IngestionIngestion

Entry Points - InhalationEntry Points - Inhalation

Inhalation (through respiratory system)Inhalation (through respiratory system)– Major route of entryMajor route of entry

– The amount of a toxic substance that can be The amount of a toxic substance that can be inhaled depends on:inhaled depends on:• Concentration of the substanceConcentration of the substance

• Duration of exposureDuration of exposure

• Breathing volume Breathing volume

Entry Points - AbsorptionEntry Points - Absorption

Absorption (through skin) Absorption (through skin) – Corrosives - acids and alkalis progressive Corrosives - acids and alkalis progressive

burns burns – Dermatitis - removal of the oils from the Dermatitis - removal of the oils from the

skinskin– Eye Damage - most damaging, because of Eye Damage - most damaging, because of

sensitivitysensitivity– Rates depends - temperature, body site, Rates depends - temperature, body site,

molecular size, degree of ionisation, lipid molecular size, degree of ionisation, lipid solubility and aqueous solubilitysolubility and aqueous solubility

Entry Points - Ingestion & InjectionEntry Points - Ingestion & Injection

Ingestion (intestinal track)Ingestion (intestinal track) - not a major - not a major concern in industrial settingconcern in industrial setting– Gastrointestinal Absorption- substance is Gastrointestinal Absorption- substance is

ingested unknowingly.ingested unknowingly.– Washing hands prior to eating is an Washing hands prior to eating is an

important means of preventing accidental important means of preventing accidental poisoningpoisoning

• Direct Injection (needle and syringe)Direct Injection (needle and syringe)– Not often a route entryNot often a route entry– Introduce in experiments involving animalsIntroduce in experiments involving animals

Effects of Toxic MaterialsEffects of Toxic Materials• Acute effects/exposuresAcute effects/exposures

– Sudden dose of a highly concentrated substanceSudden dose of a highly concentrated substance– Effect can be severeEffect can be severe– Typically just one accidentTypically just one accident– Cause immediate health problemsCause immediate health problems

• Chronic effects/exposuresChronic effects/exposures– Limited continual exposure over timeLimited continual exposure over time– Health problems develop slowlyHealth problems develop slowly– Limited concentrationLimited concentration– Progressive accumulationProgressive accumulation– Little or no awareness of exposuresLittle or no awareness of exposures

Airborne ContaminantsAirborne Contaminants

• Dusts - solid particlesDusts - solid particles

• Fumes - welding, heat treatingFumes - welding, heat treating

• Smoke - incomplete combustionSmoke - incomplete combustion

• Aerosols - very small liquid or solid particlesAerosols - very small liquid or solid particles

• Mists - tiny liquid dropletsMists - tiny liquid droplets

• Gases - formless fluidsGases - formless fluids

• Vapours - solid or liquid at room temperature Vapours - solid or liquid at room temperature turn to vapours when heated Toxic turn to vapours when heated Toxic SubstancesSubstances

Effects of Airborne ToxicsEffects of Airborne Toxics

Narcotics/ Anesthetics

Narcotics/ Anesthetics

AsphyxiantsAsphyxiants

IrritantsIrritants

Effects of Airborne ToxicsEffects of Airborne Toxics

– Irritants:Irritants: irritation to skin, eyes and the irritation to skin, eyes and the inner lining of the nose, mouth, throat and inner lining of the nose, mouth, throat and upper respiratory tractupper respiratory tract

– Asphyxiants:Asphyxiants: substance that can disrupt substance that can disrupt breathing so severely that suffocation can breathing so severely that suffocation can resultresult

– Narcotics/Anesthetics:Narcotics/Anesthetics: high dose can high dose can cause unconsciousness and even deathcause unconsciousness and even death

Ventilation and The “Sick-Building” Ventilation and The “Sick-Building” SyndromeSyndrome

• Sick building makes people sick because it Sick building makes people sick because it has become infested with mould, fungi, has become infested with mould, fungi, spores and other airborne micro- spores and other airborne micro- organismsorganisms

• Health problems commonly associated Health problems commonly associated with poor indoor air quality include allergic with poor indoor air quality include allergic reactions, respiratory problems, eye reactions, respiratory problems, eye irritation, bronchitis etc.irritation, bronchitis etc.

Sick Building Syndrome RemedySick Building Syndrome Remedy

• A key to prevent and eliminate sick building A key to prevent and eliminate sick building syndrome - air exchangesyndrome - air exchange

• Important factors in a building’s ability to Important factors in a building’s ability to eliminate contaminated air and bring in fresh air eliminate contaminated air and bring in fresh air areare

– ventilationventilation– air infiltration ratesair infiltration rates– airflow rates in ductsairflow rates in ducts– airflow patternsairflow patterns– fume exhaustfume exhaust

Confined SpaceConfined Space

A A confined spaceconfined space has limited or has limited or restricted restricted means ofmeans of entry or exitentry or exit, is large enough for an , is large enough for an employee to enteremployee to enter and perform assigned work, and perform assigned work, and is and is not designed fornot designed for continuous occupancy continuous occupancy by the employee. by the employee.

These spacesThese spaces may include, but are not limited may include, but are not limited to, underground vaults, tanks, storage bins, pits to, underground vaults, tanks, storage bins, pits and diked areas, vessels, andand diked areas, vessels, and silos. silos.

Confined Space HazardsConfined Space Hazards

Why is confined space hazardous? Why is confined space hazardous?

• It is their It is their potential to trap toxic and/or potential to trap toxic and/or explosive vapours and gases explosive vapours and gases (hazardous (hazardous atmosphere.atmosphere.

• Definition by OSHA on hazardous Definition by OSHA on hazardous atmosphere: atmosphere:

““flammable gas, vapour or mist in excess of flammable gas, vapour or mist in excess of its lower flammable limit”its lower flammable limit”

Flammable Limits (Fire Hazards)Flammable Limits (Fire Hazards)

• LFL - LFL - LLower ower FFlammable lammable LLimitimit is the lowest is the lowest concentration of a gas or a vapour that concentration of a gas or a vapour that can generate a flame when in presence of can generate a flame when in presence of a sufficient ignition source.a sufficient ignition source.

• UFL - UFL - UUpper pper FFlammable lammable LLimitimit is the is the highest concentration that can propagate a highest concentration that can propagate a flame.flame.

Flammable/explosive Range for Flammable/explosive Range for Vapours and GasesVapours and Gases

Flammable/explosive

range

100% Air100% Air 0% Air0% AirAIRAIR

LFLLFL UFLUFL

0% Gas0% Gas 100% Gas100% Gas

GASGAS

Confined Space Hazards PermitConfined Space Hazards Permit

A A permit-required confined spacepermit-required confined space is is one that meetsone that meets the definition of a confined the definition of a confined space and has one or morespace and has one or more of these of these characteristics:characteristics:

(1)(1) contains or has thecontains or has the potential to contain a potential to contain a hazardous atmosphere, hazardous atmosphere,

(2)(2) contains a material that has the potential contains a material that has the potential for engulfingfor engulfing an entrant, an entrant,

(3)(3) has an internal configuration that mighthas an internal configuration that might cause an entrant to be trapped or cause an entrant to be trapped or asphyxiated byasphyxiated by inwardlyinwardly

Entry to Confined Space StepsEntry to Confined Space Steps

• Shut down equipment/powerShut down equipment/power

• Test the atmosphereTest the atmosphere

• Ventilate the spaceVentilate the space

• Have a rescue personnel stand byHave a rescue personnel stand by

• Maintain communicationMaintain communication

• Use a lifelineUse a lifeline

Hazard Recognition and EvaluationHazard Recognition and Evaluation

• The degree and nature of the hazard must The degree and nature of the hazard must be understood before effective hazard be understood before effective hazard control procedures can be developed.control procedures can be developed.

• Hazard evaluation Hazard evaluation – nature of material involvednature of material involved– intensity of the exposureintensity of the exposure– duration of the exposureduration of the exposure

Prevention and ControlPrevention and Control Most prevention and control strategies can be Most prevention and control strategies can be

placed in on of the following four categories:placed in on of the following four categories:• Engineering controlsEngineering controls

– Less hazardous material, redesign a process, isolate hazardous Less hazardous material, redesign a process, isolate hazardous processprocess

• VentilationVentilation– Exhaust ventilation, dilution ventilationExhaust ventilation, dilution ventilation

• Personal protective equipmentPersonal protective equipment– Last resort; safety goggles, face shields, gloves, boots and Last resort; safety goggles, face shields, gloves, boots and

respiratorsrespirators

• Administrative controlsAdministrative controls– Rotating schedules, work shifts, required breaksRotating schedules, work shifts, required breaks

• Good housekeepingGood housekeeping• Self-protection strategiesSelf-protection strategies