Chapter 5 Physical Agents & Chapter 6 Biological and Chemical Agents PDF

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iChapter 5: Physical Agents Blue light ● Electronic devices emit blue light ● Blue light (a part of the visible light spectrum) has a much shorter wave than other colour lights, resulting in a higher energy level, reaching further into our retinas, and having a greater impact on us ● While blue light has a number of benefits, exposure to it before sleep can be detrimental to our health ● Exposure to blue light affects our ability to produce melatonin Physical Agents: sources of energy that may cause injury or disease (i.e noise, vibration, radiation, temperature, pressure) Ambient: all-encompassing condition associated with a given environment, being usually a composite of inputs from sources all around us Radiation: ● Every day and every minute we are exposed to radiation ● In general, radiation is the emission of electromagnetic energy 2 Types 1. Ionizing Radiation a. Capable of producing ions (i.e. X-rays, gamma rays) b. Radiation exposure is measured in rem c. Natural radiation is approx. 125 rem per year. d. Dose of approx. 75 rem per year can cause serious health effects e. Effects of electromagnetic radiation upon humans / animals depends on the power and frequency of the radiation 2. Non-ionizing Radiation a. Refers to electromagnetic radiation that does not have energy great enough to turn matter into ions b. We can be exposed to it without causing significant impairments or damage to body tissues (i.e. sun rays, cellular telephones) Controlling Radiation ● Requires various engineering and administrative controls ○ Engineering controls can include shields, walls, locked doors, warning indicators, ventilation systems ○ Admin controls include regular inspections, maintenance schedules, operating procedures, proper labelling and inventory of radioactive devices or materials

Noise: ● Any unwanted sound -- referred to as the most common workplace hazard ● Early warning change: deterioration of hearing in the upper frequency, earliest detectable sign of noise induced hearing loss ● This is complex in the workplace b/c sound considered to be noise by one individual may not be considered noise by another -- variance circumstances ● Sound is measured by Hertz or Hz ● “Threshold of hearing” refers to the range of sound that a human ear can perceive or hear ○ This is measured by decibel, or dB ○ Measured on a logarithmic scale, so a very small difference in numbers translates into very large actual differences ○ A 3 dB diff represents a doubling of the “loudness” ● Human hearing is condition on 3 characteristics: ○ Frequency ○ Duration ○ Loudness Types of Hearing Loss: 1. Conductive a. Restricts the transmission of sound to the cochlea or inner rear b. Caused by wax buildup, infection, or trauma c. Unhygienic application of hearing protectors or improper cleaning of these devices 2. Sensorineural a. Aka nerve deafness, usually irreversible b. Caused by excessive noise levels at work are ringing in the ears (tinnitus) 3. Gradual hearing loss (aka Temporary Threshold Shift - TTS) a. Can sometimes be reversed by removal from the noise source 4. Permanent Threshold Shift (PTS) a. Identifies a hearing disability that is permanent and may not be correctable b. In most cases, a hearing aid can bring some improvement. 5. Some reasons are more physiological: ● Vasoconstriction: process of causing a constriction of the blood vessels ● Hyperreflexia: unusually quick reaction by the nerves to some external stimulus Noise Control: ● Elimination is the first strategy ● Next course of action if not possible, is to change the source and make the source quieter ● Next would be moving the worker away from the source or erecting sound barriers between

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Based on the physics of noise, if the distance from sound source is doubled, the noise level will drop by a fixed amount Attenuated: reduction of noise at one location compared to another farther from the source Third strategy involves PPE (personal protective equipment) -- earplugs, earmuffs

Vibration: ● Refers to the oscillating motion of a particle or body moving about a reference position ● Measured by examining the frequency, amplitude, and acceleration of an object ● Often easily detectable 2 categories: 1. Low frequency 2. High frequency Health Effects of Vibration: ● Segmental vibration: vibrations that affect only parts of the body (i.e. use of a jackhammer) ● Whole-body vibration: affect the whole body as a unit ● Vibration is a health hazard for 3 reasons

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Motion sickness, fatigue, nausea, stomach problems, headache -- sometimes connected to bowel, back disorders etc Inhibition of muscular reflexes, impaired or blurred vision, alterations of brain electrical activity As frequency increases, necrosis (death or decay of tissue) or decalcification (loss of lime salts [calcium] in the bones)

Resonance: effect that occurs when an object reacts strongly to some particular frequency Controlling Vibration:

Thermal Stress: Thermal stress conditions involve cold and hot temperature extremes Homeostasis: balance of heat generation

3 methods of heat transfer: 1. Conduction: heat transfer occurring when two surfaces are in contact 2. Convection: heat transfer occurring when one surface adds heat to the surroundings 3. Radiation: heat transfer occurring when energy is transmitted by electromagnetic waves

Heat-related illnesses ● Health weight age low fitness level and medical conditions influence the risk that heat poses to an individual ● Heat edema occurs mostly in individuals who are not acclimatized to working in hot environments -- results in body swelling (ankles) ● Heat rash is the first sign of the body’s intolerance to heat and results in the sweat glands becoming swollen and plugged ● Heat cramps are the result of an imbalance of salt in the body and are often felt in the arms and legs first ● Heat syncope = fainting is the result of inadequate blood in the brain due to lowered blood pressure ● Heat exhaustion occurs when an individual is sweating excessively and loses too much body water ● Heat stroke occurs when the body is unable to control its thermal balance, resulting in dangerous rise in core temp. Controlling Heat ● If employees are at risk for heat-related illnesses, employer is required to conduct heat assessments and implement the proper controls ● Engineering controls are the most effective method -- shielding, providing AC, increasing ventilation ● Admin controls also if latter is not feasible -- reducing worker activity, proper supervision, work-rest cycles ● Personal protective equipment is also effective

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PPE should be used in combination with other admin and engineering control mechanisms

Cold Environments: ●

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Key factors influence the body’s response to the cold: ○ Air temperature, wind speed, humidity, physical activity, work schedule and protective clothing Cold-related injuries are labelled as non-freezing injuries or freezing injuries ○ Non-freezing is when body parts cool but do not freeze (trench foot, chilblains, immersion foot) ○ Freezing injuries occurs in colder temperatures and are caused by local freezing of muscles and tissues -- ie. frostbite or frostnip Hypothermia occurs when cold causes the body’s ability to regulate its thermal temp to fail, and the body is not able to compensate for the loss of heat ○ Requires immediate first aid and treatment

Controlling Cold: - Engineering, admin + PPE mechanisms to reduce risk of cold-related injury or illness - Heaters, shields - Work and rest schedules - Procedures such as shutdown or closure - Clothing is one of the most effective methods for reducing the risk - Protective clothing should be carefully selected based on legislation and conditions of the environment and nature of the work

Chapter 6: Biological and Chemical Agents ●

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Biological materials are made up of microorganisms, proteins, or nucleic acids ○ Biohazards = hazards created by exposure to infectious microorganisms, proteins, or nucleic acids > hazardous biological materials Chemicals are compounds that are purified, often artificially, using chemistry ○ Chemical Agent = hazards created by exposure to chemicals > chemicals that pose a threat to our health and safety Agents = any substances - chemical, biological or physical - to which a human may be exposed at work or at home Majority of biological and chemical materials that pose a threat to us are listed in the WHMIS and Global Harmonized System (GHS) Biohazards Biological agents are often referred to as biohazards when they pose a risk to our health and safety (i.e. result in disease, allergic reactions & infections) Biohazards are very difficult to see to the naked eye = difficult to perceive the risk w/ them Biological Agents (pg135):

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Ppl most at risk are those who work in specialized fields (ex. medicine, research, farming) but the public is at risk (ex. cold, flu) In order for biohazards to infect humans, certain conditions must be met & they all make up: ○ Chain of Infection = the process and conditions by which biological agents are spread from one host to another ■ If a link/condition is interrupted that transmission stops Reservoir = the home or environment where the biological agent grows and multiplies ○ Ex. humans, animals, and ground Portal of Exit = the path by which a biohazardous agent leaves its host ○ Ex. chest infections exit via respiratory tract Mode of Transmission = the means or channel by which an agent is carried from one host to another (through direct contact or indirectly like air) ○ Ex. skin to skin, insects, etc Portal of Entry = the path by which a biohazardous agent gains access to a new post ○ Ex. respiratory tract Susceptible Host = an individual or animal that becomes infected with a biohazardous agent Chain of Infection (pg 136):

Chemical Agents ● ● ● ●

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Chemicals are a necessary part of our everyday lives, to minimize any negative impact, they need to carefully managed Health problems created by chemical exposures are more prevalent in the workplace Hazard associated w/ a material is defined as the likelihood that it will cause injury in a given environment/situation Potential degree of seriousness of the hazard is determined by the toxicity OR its explosive properties (i.e. defined by flammability and reactivity) ○ Toxicity = ability to cause injury to human biological tissue ○ Other factors include concentration of chemical and length employee was exposed to it Chemicals exist in 3 main states: solid, liquid, and gas ○ State of the chemical helps you understand the health risks in poses to us & how it enters us Most negative effects of exposure are derived from airborne respiratory contaminants: ○ Aerosols = airborne respirable contaminants, such as liquid droplets or solid particulate, dispersed in air, that are of a fine enough particle size (0.01 to 100 micrometres) to remain suspended for a time

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Toxicology: An Overview Toxicology is the scientific study of poisons > pt of understanding chemical related occupational illnesses Ototoxicity = chemicals having adverse/harmful effect on the nerves and/or bones required for hearing and balance Toxicity Terminology:

● Similar to bio agents, chemicals may enter the body by 1 of 4 portals of entry: 1. Respiration (Inhalation) ● 5 basic levels of protection w/in the respiratory tract: 1. Nose / Upper Respiratory Tract> lined w/ hairs / cilia act as a course filter 2. Interior Nasal Passage > turbinates are found > act as humidifiers 7 heat exchangers ● Turbinates = spiral or spongy sections of the respiratory system that have a centrifugal effect to help remove aerosols 3. Back of Throat > hairs/cilia are coated in mucus > entraps the finer particulates which is then removed by blowing nose/clearing throat 4. Lung Passages > bronchi and bronchiole > air flow & its turbulence from breathing expelled by normal exhalation 5. Alveoli = tiny air sacs > located at the end of the lung’s air passages (= alveolar ducts) ● These sacs contain small cells called macrophages which expose of impurities through lymph system 2. Skin Absorption ● Fat soluble chemicals are readily absorbed through the skin & gases pass through skin very quickly

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Chemical’s ability to easily pass through the skin is associated w/ its toxicity ex. Some pesticides absorb very quickly through the skin

3. Ingestion ● Ingestion of solvents isn’t as major of an issue absorbing through the skin/lungs ● Poor personal hygiene can cause this ex. eating or smoking where solvents can be used ● Ingested solvents > cause damage to lining of the digestive tract ● Ingested solvent may be absorbed into the bloodstream and carried to target organs which can cause toxic effects or worse destroy the surfactant layer ○ Target Organs = tissues or organs that are most affected by exposure to a particular substance ○ Surfactant Layer = layer of liquids in the digestive tract and elsewhere (i.e. cardiovascular system) that modify or reduce the surface tension w/in the conductors (intestine, blood vessels) to allow material (blood, food, stools, and so on) to move easily 4. Penetration ● Penetration occurs when the skin is cut / punctured by a sharp obj ● Disorder range can range from low grade infections to HIV

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Characteristics and Properties of Solvents 8 general characteristics/properties that make solvents effective but hazardous & toxic: 1. Low Surface Tension = allows a solvent to spread evenly & quickly and to provide excellent wetting of contact surfaces ○ Wetting factor > allow for it to slip into cracks & remain there = toxic vapours 2. High Vapour Pressure = vapour pressure increase w/ temp = increases the volume/concentration of a generated vapour/gas 3. Low Boiling Point = lower the boiling pt, the greater the rate of evaporation/generation of vapours of liquids > greater the health risk to be generated at lower temps ○ Boiling Point = temperature at which the vapour pressure of a liquid equals atmospheric pressure 4. Low  Heat of Vaporization = relates to the amount of heat/energy required to change a liquid into a gas/vapour 5. High Volatility =  solvent’s effectiveness is the speed it will evaporate; greater volatility = faster evaporation = greater health and fire risk 6. Ability to Dissolve Fats = when solvents are in contact w/ the skin, the skin’s surface oils are dissolved and unprotected skin becomes more receptive of trauma; major cause of: ○ Dermatitis = the inflammation of the skin from any cause

7. Flammability = is one of the main hazards associated w/ solvent use since all organic solvents are flammable ○ (a) Flash Point = lowest temp where liquid gives off enough vapour to form an ignitable mixture w/ air and produce a flame > if FP is close to rm temp, danger of ignition is greater ○ (b) Lower Explosion Limit (LEL = Lower Flammability Limit) = smallest fuel-air mixture that is ignitable ○ (c) Upper Explosion Limit (UEL = Upper Flammability Limit) = highest fuel-air mixture that is ignitable ○ (d) Auto-ignition Temperature = lowest temp where a flammable fuel air mixture will ignite from its own heat source (ex. Hay in a barn) 8. Vaporization = most solvents will form very large volumes of vapour from a small amount of liquid Inorganic Solvents ● Inorganic solvents fall into 2 classes: acids and bases ● Difference b/w acids and bases are pH (= the degree of acidity/alkalinity of a solution) ○ Scale 1 - 14; 7 = neutral (neither acid/base); 1 = extreme acidity; 14 = extreme alkalinity ○ Acids = highly corrosive and are used for refining/processing materials ■ Cause mostly burns resulting from inhalation/skin contact ■ Chromic acid (= carcinogen & sensitizer) > ex. Black holes left on skin due to corrosive attacks ○ Bases = alkalines are usually used to etch/dissolve a variety of materials (ex. melts ice on roads) Organic Solvents

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Organic solvents are petrochemically based; Can be identified by their molecular structure and can be grouped under 10 classifications (pg 147):

Control of Exposures Safe use & handling of chemical and biological agents can be ensured only through active employment of a variety of precontact and point of contact measures (pg 148) Engineering Controls Best method for mitigating the risk associated w/ chemical & biohazards is elimination If not possible, then reduce risk by finding less harmful alternatives Engineering controls for BH include built in protective systems, equipment/supplies (often built ahead of time and built into design of workplace) ○ Ex. ventilation systems, construction seals, sharp disposal containers for needles, automated equipment like toilets and sinks (in hospitals & restaurants)

2. Administrative Controls ● Education and training of all employees in safe work practices ● Training in safe operating and emergency procedures in the use and care of PPE and handling agents ● Workplace Hazardous Materials Information System (WHMIS) = comprehensive communication system designed to outline the safe use of hazardous products via labels, safety data sheets (SDS) and worker edu, and training programs

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2015, WHMIS incorporated the Globally Harmonized System (GHS) of Classification and Labelling of Chemicals for workplace chemicals due to various methodologies used around the world ■ Goal = develop consistent policies, practices and standards w/ other countries that use GHS ○ WHMIS is based on 3 Elements: 1. Labels designed to alert the worker that the container contains a potentially hazardous products 2. Safety data sheets outlining a product’s potentially hazardous ingredient(s) and procedures for safe handling of the product 3. Employee training ○ Main Difference w/ WHMIS 1998 vs 2015: 1. New rules for classifying hazardous workplace chemicals: 2 main hazard classes (physical hazards and health hazards) 2. New label requirements, including pictograms instead of symbols that correspond to hazard classes 3. Different format for safety data sheets (formerly material safety data sheets - MSDS) Hazard Classes and Categories Labels ○ Workplace labels must contain the product name, outline measures for safe handling and refer to the safety data sheet if one is available ○ Supplier labels must have info in French and English fo (pg 151): ■ Product identifier ■ Initial supplier identifier ■ Pictograms = hazard symbols w/ red square around it ■ Signal word - i.e. danger, warning ■ Hazard statement - i.e extremely flammable ■ Precautionary statement - i.e. protect from sunlight ■ Supplemental label info Safety Data Sheets ○ Obj of SDS is to identify potentially harmful materials, to present info about the nature of the materials and harmful effects and to provide guidance on how to handle safely ○ manufacturer/supplier must have SDS for each product: ■ They are regulated by federal legislation under the Hazardous Products Act and provincial/territorial regulations ■ Employers are regulated only by provincial/territorial regulation ● If employer makes a product for use they become responsible for SDS ○ 16 items need to appear on SDS (12 - 15 are not required by Canada): 1. Identification

2. Hazard identification 3. Composition/ingredients 4. First aid 5. Firefighting 6. Accidental release measures 7. Handling/storage 8. Exposure controls/Personal protection 9. Physical/Chemical properties 10. Stability/Reactivity 11. Toxicology Info 12. Ecological Info 13. Disposal considerations 14. Transportation info 15. Regulatory info 16. Other info (i.e. last time SDS was reviewed) Education and Training ○ WHMIS education refers to providing info about how the WHMIS/GHS is structured, its purpose and objectives, and the hazards associated w/ each material ○ Training can be viewed as more job specific info and covers procedures for handling, storage, use, disposal, and emergency proc...