Workplace Environmental Health Issues PDF

EVSM 5230 Workplace Environmental Health Issues Dr. LAM Ka Wo September 24, 2024 Components of Environmental Health Occupational Environmental Health Ambient Domestic Community Occupational Hazards ...

EVSM 5230 Workplace Environmental Health Issues Dr. LAM Ka Wo September 24, 2024 Components of Environmental Health Occupational Environmental Health Ambient Domestic Community Occupational Hazards  Chemical Hazards  Physical Hazards  Biological Hazards  Ergonomic Hazards Different types of Hazardous Materials Performance Standards - Chemicals  American Conference of Governmental Industrial Hygienist (ACGIH) publishes Threshold Limit Values (TLVs) for over 700 industrial chemicals every year  Another 100+ chemicals are understudy  TLVs are adopted by governments all over the world as regulatory exposure limits  Chemical Hazards Exposure Monitoring  Direct reading ◼ Special instruments by infrared absorption, photoionization, gas chromatography, etc. ◼ Detector tubes by colorimetric chemistry  Air sampling and laboratory analysis ◼ Personal sampling pumps plus sampling media (sorbent, filter) & accessories ◼ Diffusive samplers (mainly volatile organics)  Professional judgment  Laboratory Analysis  Volatile Organics – ◼ Gas Chromatograph (GC) with: Mass Spectrometer (MS), Flame Ionization (FID) or Electron Capture (ECD) Detectors  Semi-Volatile Organics – ◼ High Pressure Liquid Chromatography (HPLC)  Laboratory Analysis  Anions – ◼ Liquid Chromatography (LC)  Metals – ◼ Atomic Absorption Spectrometer (AA), ◼ Inductively Coupled Plasma Spectrometer (ICP) Points of Intervention EMISSION SOURCE AIR PATH WORKER Substitution Process change Change air direction Move worker out of path Automation Dilution ventilation Training and education Process enclosure Increase distance Enclosure Process isolation Erect barrier Respiratory Protection Dry to wet methods Rotation Local exhaust ventilation Preventive Maintenance Engineering Control Administrative Control Personal Protective Equipment Chemical Hazards Hierarchy of Controls Type of controls in examples descending preference Elimination Do not use hazardous material whenever possible Substitution Use less hazardous material Engineering Mechanical Enclosure Administrative Limit access to hazardous materials, training, signs & label, safety procedures, work shifts PPE Gloves, respirators, goggles, etc  Substitution examples Original Subs Carbon tetrachloride 1,1,1-trichloroethane Benzene Toluene, cyclohexane, ketones Pesticides Natural repellants Fume, dusts Pellets, ingots Engineering Controls – Local Exhaust ventilation  Even (laminar) air flow https://youtu.be/A4AHxLnByts  Adequate air velocity, usually about 0.5 m/s at opening (i.e. face velocity)  Adequate capture velocity at source of contaminant (a factor of air velocity and distance from opening)  Sufficient make up air Fixed Exhaust Pipe Examples of PPE Respirator Types  Fit Test for Respirators 22  All tight-fitting respirators must be fit tested  Individual respirator user with unique facial dimensions in width and length  Required ◼ For each respirator used by employee Respirator fit testing exercise: ◼ Once per year 1. Normal breathing 2. Deep breathing 3. Head side-to-side 4. Head up and down 5. Talking 6. Grimace 7. Bending of body 8. Normal breathing HAND PROTECTION - SELECTION OF RIGHT GLOVES IS CRUCIAL  “Rubber” gloves ◼ Latex ◼ Butyl ◼ Polyvinyl Chloride (PVC) ◼ Nitrile Prof Wetterhahn died  Butyl, Isobutylene- Isoprene Rubber (IIR) because she used  Neoprene, Chloroprene the wrong gloves  Polyethylene (PE) https://www.bing.com/videos/search?q=karen+wetterha hn+dartmouth&&view=detail&mid=31D71CDD5F37214  Polyurethane (PU) F538531D71CDD5F37214F5385&FORM=VRDGAR 23  Polyvinyl Alcohol (PVA) GLOVE SELECTION  Glove Materials  Length ◼ Chemical ◼ Elbow-length resistance ◼ Wrist/ forearm length ◼ Thermal protection  Disposable Vs reusable ◼ Mechanical  Type of job involved strength ◼ Thickness vs dexterity ◼ Frequency of usage 24  CHEMICAL RESISTANCE  Protective clothing provide resistance to ◼ Penetration  Bulk flow of chemical through closures, porous materials, seams and pinholes or other imperfections in the protective gloves ◼ Permeation  Chemical migrates through protective glove at a molecular level ◼ Degradation  A deleterious change in any physical and/or chemical property of a protective glove material All chemicals will eventually permeate protective clothing https://www.youtube.com/watch?v=6LPPJkdxKbY 25 SELECTION OF CHEMICAL PROTECTIVE GLOVES AND CLOTHING  MSDS  Databases ◼ Instant Glove ◼ CPC Database  Commercial manufacturers websites ◼ Best Glove ◼ North 26 ◼ Ansell Physical Hazards Physical Hazards  Noise  Vibration  Ionizing and non-ionizing radiation ◼ Will be covered in another lecture  Extremes of temperature and pressure Physical Hazards Noise Definition:  Noise (unwanted sound) is a form of vibration conducted through solids, liquids, or gases  Health Effect of Noise  Noise induced hearing loss  Interference with communication - safety hazard  Psychological effects (stress, annoyance, increase in blood pressure, loss of concentration) https://www.noisyplanet.nidcd.nih.gov/p arents/what-is-noise-induced-hearing- loss https://youtu.be/krqGja-pDcc 30 Physical Hazards Noise Factors:  Variation in individual susceptibility  Frequency of the noise  Continuous, intermittent, or impact  Exposure duration  Noise  Noise (unwanted sound) is a form of vibration conducted through solids, liquids, or gases  Audible range of frequency for human: 20 Hz to 20,000 Hz  Sound levels are measured in decibels (dBA) by sound level meters (ambient) or dosimeters (personal) 32 Performance Standards - Noise  ACGIH TLVs – Noise Exposure  Aim at protection of hearing  Specify sound pressure levels and duration of exposure  3 dB doubling – increase of 3 dB means twice as loud  Measures environments > 80 dBA Performance Standard – Continuous Noise Sound Level in dBA Allowable Duration 85 8 hours 88 4 hours 91 2 hours 94 1 hour 97 30 minutes 100 15 minutes Performance Standard – Impulse and Impact Noise  Measurement range 80 – 140 dBA  Average within 85 dBA  Impact noise peak < 140 dB https://www.cdc.gov/niosh/topics/noise/app.html When Noise Level Exceeds Allowable Limit  Need to implement hearing conservation program: ◼ Engineering noise reduction ◼ Hearing protection ◼ Audiometric testing ◼ Training https://www.youtube.com/watch?v=bP-nJp3yBK4  Physical Hazards Noise Controls  Acoustical engineering ◼ Isolation of vibration ◼ Acoustical insulation  Remote operations  Job rotation/work shift arrangement  Ear plugs and muffs  Hiring deaf workers to perform noisy operations? http://www.youtube.com/watch?v=U47jYm4IDII  Workplace Noise Control Source Enclosure Acoustical Engineering Engineering Controls Remote operation Replacement of machine Acoustical insulation Isolation of vibration Job rotation / Ear muff / ear plugs Work shift PPE Administrative controls 38 Hearing Protection Devices https://www.youtube.com /watch?v=vtIcqkjZG1s Vibrations  Physical Hazards - Vibration  Sources: Earth-moving vehicles, pneumatic hand tools  Hazards: bone & joint disorder, tingling & numbness in fingers & hands, vascular disorder, e.g. Raynaud’s syndrome, motion sickness  Evaluation: accelerometer  http://media.bigoo.ws/content/gif/peoples/peoples_143.gif https://www.youtube.com/watch?v=nmrpY5ntf4U http://www.cpwrconstructionsolutions.org/structural_steel/hazard/ 711/drill-grind-and-saw-materials-hand-arm-vibration.html http://wpcontent.answcdn.com/wikipedia/commons/thumb/f/fc/Ray naud%27s_Syndrome.jpg/230px-Raynaud%27s_Syndrome.jpg http://www.daviddarling.info/images/Raynauds_disease.gif http://www.whitefinger.co.uk/index_files/hand.jpg Performance Standard - Vibration ACGIH – TLVs Specify acceleration levels and allowable period of exposure Component acceleration Total Daily Exposure m/s2 g Duration 4 0.40 4 to 8 hours 6 0.61 2 to 4 hours 8 0.81 1 to 2 hours 12 1.22 Less than 1 hour Vibration Exposure Controls  Anti-vibration tools  Anti-vibration gloves  Proper work practices – ◼ Keep hand and body warm ◼ Minimize vibration coupling between body and tool  Medical surveillance Biological Hazards Definition: Biological agents or substances which present a hazard to human health or well being. Biological Hazards Definition: Biological agents or substances which present a hazard to human health or well being. - Bacteria, fungi, viruses, rickettsiae, chlamydiae, parasites, recombinant DNA products, allergens, cell cultures, toxins and clinical specimens. Major Types of Biohazards  Infectious agents ◼ Microorganisms (bacteria, fungi, viruses and parasites) and arthropod vectors ◼ Clinical specimens (blood-borne pathogens) ◼ Cell cultures ◼ Experimental materials (e.g. sewage) ◼ Indoor air  Laboratory animals  Biological toxins  Recombinant DNA molecules Workers who May Encounter Biohazards  Clinical and research laboratory workers ◼ Bodily fluids and tissue, Recombinant DNA  Health care workers ◼ Infectious organisms  Animal handlers ◼ Zoonotic agents  Animal and food processors ◼ Zoonotic agents, antibiotics resistant germs  Building maintenance workers ◼ Legionnaires disease agent, allergens, toxins  Sewage and compost facilities ◼ Enteric pathogens  Classification of Biohazards  Many agencies classify microorganisms according to their degree of hazard ◼ US Centers for Disease Control and Prevention (CDC) ◼ US National Institute of Health (NIH) ◼ Health Canada ◼ European Council (EC)  All lists use similar criteria  Usually 4 classes ranking from low to high hazard  Primarily based on human pathogenicity  The lists are dynamic in nature  Classification is “flexible” with appropriate special risk assessment and controls Class I Agents  All non-pathogenic microbes  Some are opportunistic pathogens  Examples: ◼ Pseudomonas sp. ◼ Aspergillus sp.  Class II Agents  Pathogenic microbes  Diseases are easily treatable if recognized early  Examples: ◼ Salmonella sp. ◼ Legionella pneumophila ◼ Neiserria gonorrhoeae  Class III Agents  Highly infectious pathogenic microbes  Diseases can be serious and life threatening  Example: ◼ Mycobacterium tuberculosis ◼ Yersinia pestis ◼ Coccidiodes immitis Class IV Agents  Highly infectious pathogens that can easily spread in the community  Diseases are often fatal  Examples: ◼ Herpes Simiae Virus ◼ Yellow Fever Virus ◼ Venezuela Equine Encephalitis Virus ◼ certain rickettsial and chlamydial agents For More Information on Safety Classification of Microbes...  Risk Group Database for Infectious Agents (American Biological Safety Association) https://absa.org/rgdb/  Pathogen Safety Data Sheets for Infectious Agents (Health Canada) https://www.canada.ca/en/public-health/services/laboratory-biosafety- biosecurity/pathogen-safety-data-sheets-risk-assessment.html Biological Hazards Controls  Facility design to contain bioaerosols  Air purification by HEPA filter  Biological safety cabinets in labs  Personal hygiene  Waste & facility decontamination  Maintenance of ventilation system  PPE - Respirators and gloves Biological Safety Levels  Based on US CDC definitions  Corresponds to Classes of microbes (BSL 1-4 for Class 1-4 organisms)  Animal BSL (ABSL 1-4) for animal work  Each level builds on the previous level  Main elements: ◼ laboratory practice and techniques ◼ safety equipment (primary barriers) ◼ facility design (secondary barriers) https://www.youtube.com/watch?v=xNYASNEdgg8 Biosafety Level 1 Laboratory Facilities (Secondary Barriers) Biosafety Level 2 Laboratory Facilities (Secondary Barriers) Biosafety Level 3 Laboratory Facilities (Secondary Barriers) High Efficiency Particulate Air Filter (HEPA)  An important tool for controlling biohazards  Critical component in biosafety cabinet, air filtration systems, negative pressure air purifying respirators Definition of HEPA Filter  A throw-away extended/pleated medium dry-type filter with: ◼ rigid casing enclosing the full depth of the pleats ◼ minimum particulate removal of 99.97% particles with a diameter of 0.3 micron HEPA Filter Electronic micrograph Electronic micrograph Of Of Clean HEPA filter Dirty HEPA filter  Particulate Capture Mechanisms  Filtering devices (e.g. sieves and filter papers) for very large particles rely on pore sizes  Different mechanisms remove submicron particles down to the range of large gas molecules: ◼ impact and interception (efficient for larger particles) ◼ diffusion (efficient for smaller particles)  0.1-0.3 is at the boundary where neither mechanism is efficient 0.3 Ergonomic hazards  Ergonomics Definition  “...The application of human biological science in conjunction with the engineering sciences to achieve the optimum mutual adjustment of man [sic] and his [sic] work, the benefits being measured in terms of human efficiency and well-being.” - International Labor Office (ILO)  Operator and equipment are a unified system http://www.youtube.com/watch?v=LAKlmdMHpdE http://www.youtube.com/watch?v=rGq7TVOwA60 https://youtu.be/KLkAC_eN2Hw  Ergonomic Hazards Effects  Tendons disorders ◼ Tenosynovitis (tendon inflammation), epicondylitis (“tennis elbow”)  Nerves disorders ◼ carpal tunnel syndrome  Vessel disorders ◼ Raynaud’s syndrome (“white fingers”)  Back injuries  Muscle strain Common Health Effects from ergonomic hazards  Back injuries  Slipped (vertebrate) discs  Muscle strain  Tendons disorders ◼ tenosynovitis, epicondylitis  Nerves disorders ◼ carpal tunnel syndrome  Vessel disorders ◼ Raynaud’s syndrome (“white fingers”) Tennis elbow 68 Cumulative Trauma Disorders (CTD)  Cumulative Trauma Disorders (CTDs) or Repetitive Strain Injuries (RSI) ◼ Cumulative (building up over time) ◼ Trauma (injury) ◼ Disorders (problems)  Usually upper limbs - Hands, wrists, arms, shoulder, neck 69 Occupational CTDs  Often result from awkward posture, high load or force, or high repetition, working at certain task for a long time  The tendons are overworked, and they begin to wear and tear  The hazard increases with vibration, cold, and contact with tools and work surfaces  Common problems are: ◼ Tendinitis: inflammation of any tendon (swelling and point tenderness) ◼ Tenosynovitis: tendons and the sheaths (synovium) surrounding them abrade each other, the sheaths become inflamed (swelling and pain) 70 Early warning signs of ergonomic problems  Early warning signs of ergonomic problems ◼ Swelling, numbness, discomfort, tingling, irritation, stiffness 71 Carpal Tunnel Syndrome  Inflamed tendons in the wrist (carpel tunnel) swell and compress the median nerve in the wrist  Numbness, tingling and pain in fingers; and clumsiness and loss of grip strength in the hand  Any occupation involving repetitive use of hand-held powered tools whose internal parts vibrate 72 Ergonomics Hazards Controls  Equipment design (biomechanical & behavioral)  Work station design  Work-rest scheduling  Correct postures and manual handling techniques  PPE to support body 73 Equipment Design Example PPE Against Ergonomic Hazards Work Station Design https://www.youtube.com/watch?v=8cbuO5-9jnM END