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Health Hazards

Health Hazards. The overall objective for this module is that given a Material Safety Data Sheet (MSDS), the participant will interpret health hazard information for reducing personal risk when handling a specified chemical. Overview.

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Health Hazards

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  1. Health Hazards The overall objective for this module is that given a Material Safety Data Sheet (MSDS), the participant will interpret health hazard information for reducing personal risk when handling a specified chemical

  2. Overview • Terms and definitions that will help you identify potential health hazards • Types of common health hazards and how to work with them appropriately • How to use the Material Safety Data Sheets to find health hazard information about a chemical

  3. Expectations • Define the terms: LD50, LC50, TDlo, and TClo, PEL, TLV, IDLH, and Threshold • Define the hazards; irritant, corrosive, sensitizer, carcinogen, teratogen, mutagen, reproductive toxin, anesthetic, and asphyxiant • Identify the four routes by which toxins enter the body • List five methods workers can use to reduce exposure to toxic chemicals in the workplace • Use the Material Safety Data Sheet to identify the health hazards of a chemical

  4. What is a Health Hazard?

  5. Health Hazard • Chemical, mixture of chemicals, or pathogen for which there is statistically significant evidence based on at least one study, conducted following established scientific principles, that acute or chronic health effects may occur in exposed employees. • Examples: reproductive toxins, carcinogens, hepatotoxins and neurotoxins

  6. Health Hazard • Damaging or harmful • In the early sixteenth century, Paracelsus pointed out: “All substances are poisons; there is none which is not a poison. The right dose differentiates a poison and a remedy.”

  7. Toxicology vs. Toxicity • Toxicology • Study of toxins and poisons • Includes how toxins and poisons will interact in living organisms • Based on epidemiological studies • Based on animal studies

  8. Toxicity • Rates the potential for harm of a substance • Low toxicity means relatively low risk; high toxicity means high risk for harm

  9. Factors Affecting Toxicity • Dose (concentration over time) • Route of exposure (entrance)

  10. The Hypothetical Dose / Response Curve • Dose-Response Relationship • Relationship between the dose of a chemical and the response that is produced by that chemical in a biological system • Dose-Response Curve • Show the relationship between the time of exposure to a specific amount (dose) and the effects (response) a material has on an experimental group

  11. Average Population Less Sensitive More Sensitive

  12. Response LD50 Dose

  13. Toxic Dose is based upon normal distribution and average health. Genetic variability is a major factor.

  14. Levels • Effective Dose • Amount of a toxin at which there is a response • Referred to as threshold or odor threshold • Threshold • The concentration at which toxic effects are first detected

  15. Individual Response • LD50 / LC50 (Lethal Dose 50% and Lethal Concentration 50%) • Calculation of dose / concentration of a substance that is expected to kill 50 percent of a defined population

  16. Individual Response • TDlo and TClo (Toxic Dose Low and Toxic Concentration Low) • The lowest dose or concentration of a substance which produces any toxic effect • Dose or concentration is usually lower than the LD50/LC50

  17. Exposure Limits • Airborne concentrations of a material to which nearly all individuals may be repeatedly exposed without adverse health effects • Help eliminate the factor of genetic variability

  18. Exposure Limits • ppm or ppb • used with liquid, vapor, and gas • mg/m3 • used with solid particulates suspended in air

  19. Exposure Limits • Permissible Exposure Limit (PEL) • Threshold Limit Value (TLV) • Recommended Exposure Limit (REL) • Time-weighted Average (TWA) • Short-term Exposure Limit (STEL) • Ceiling (C) • Immediately Dangerous to Life Or Health (IDLH)

  20. Exposure Limits • Permissible Exposure Limits (PEL) • Legally enforceable standard established by OSHA • Threshold Limit Values (TLV) • Guidelines established by American Conference of Governmental Industrial Hygienists (ACGIH) • Recommended Exposure Limit (REL) • NIOSH workplace exposure concentration; 10 hour average

  21. Exposure Limits • Time Weighted Average (TWA) • 8 hour day • 40 hour week • 52 weeks year

  22. Exposure Limits • Short Term Exposure Limit (STEL) • Allowable limit for a maximum of four continuous 15 minute exposures in an eight-hour day • Ceiling (C) • Concentration that may never be exceeded at any time

  23. Exposure Limits • Immediately Dangerous to Life or Health (IDLH) • Atmospheric concentration of any toxic, corrosive, or asphyxiant substance • Poses an immediate threat to life • Cause irreversible or delayed adverse health effects • Interfere with an individual’s ability to escape from a dangerous atmosphere

  24. Toxic Concentration Less than 1.0 mg/kg Dangerously Toxic 1- 50 mg/kg Highly Toxic 50 - 500 mg/kg Toxic 500 - 5,000 mg/kg Moderately Toxic 5 - 50 g/kg Low Toxic

  25. Toxic Dose (quantity vs time of exposure) The smaller the number the more toxic the dose!

  26. Cautions and Limitations for PELs or TLVs • Never be used: • Fine lines between safe and dangerous concentrations • Evaluation or control of community air pollution • Estimating toxic potential of continuous exposure • Proof of an existing disease or physical condition

  27. Route of Toxins in the Body • Inhalation • Absorption • Ingestion • Injection

  28. Route of Toxins in the Body • Inhalation • Most common toxic dose in the occupational environment

  29. Route of Toxins in the Body • Absorption • Most common route of entry for the worker

  30. Route of Toxins in the Body • Ingestion • Most common route in the home

  31. Route of Toxins in the Body • Injection • Occurs through puncture, tearing or shooting of materials through the skin by high pressure

  32. Exposure and Effects • Acute: Single exposure which occurs within 24 hrs; effect within 72 hrs • Chronic: Low level exposure over a long period; effects delayed for weeks or decades

  33. Acute Response • Headaches • Dizziness • Nausea • Eye, skin or respiratory damage • Unconsciousness • Death

  34. Chronic Exposure • Frequently not reversible • Liver, kidney, lung damage

  35. Target Organs • Affected by poisons: • CNS • Circulatory system • Blood and blood forming systems • Visceral organs (liver, kidneys, lungs, etc.) • Skin

  36. Local and Systemic Toxicity • Local: Effect of toxin at site of first contact • Systemic: Effect of toxin after being absorbed into the body

  37. Elimination of Toxins • Liver • Filters toxins out of the blood and chemically changes them into less toxic compounds • Kidney • Filters approximately 45 gallons of plasma every day waste products are passed from the kidneys to the bladder and then eliminated • Lung

  38. Substance Interaction • Additive 2 + 2 = 4 • Synergistic 2 + 2 = 6 • Potentiation 0 + 2 = 10 • Antagonism 4 + 6 = 8

  39. Response Factors • Substance • Exposure • Worker Characteristics • Environment

  40. Response Factors • Substance • Chemical composition, physical characteristics, stability, storage, and solubility in body fluids • Exposure • Dose (Concentration over time) and route of entry

  41. Response Factors • Worker Characteristics • Level of toxicity, age and body weight, nutrition, health and stress • Environment • Physical factors, social factors and other chemicals

  42. Toxic Effects of Chemical Substances • Asphyxiants • Anesthetics • Irritants • Corrosives • Sensitizers • Carcinogens • Reproductive Toxins

  43. Chemical Substances • Asphyxiant • Chemicals that deprive the victim’s body tissues of oxygen • Simple- Displace oxygen in the air • Chemical- Competes with oxygen by interfering with absorption and use of oxygen in the body • Anesthetics • Material that causes a loss of sensation or produces unconsciousness • Cause central nervous system depression

  44. Chemical Substances • Irritants • Chemical, liquid, or solid that causes a reversible inflammatory effect on living tissue at site of contact • Corrosive • Chemical that causes irreversible damage to living tissue

  45. Chemical Substances • Sensitizer • Chemical that causes a substantial number of exposed people or animals to develop an allergic reaction in normal tissue after repeated exposure to the chemical • Carcinogen • A carcinogen is any substance that has proved or is suspected to increase the risk of cancer in workers

  46. Reproductive Toxins • Mutagens • Agents that cause an inheritable change in the chemical structure of chromosomes in the cell • Changes in the structure of sex cells may be passed on to future generations • Teratogens • Substances that produce malformations of an unborn child without killing the child or causing physical harm to the mother

  47. Reducing Your Exposure • Know the identity of the chemical and the concentration of that chemical • Use the MSDS • Minimize your time working with the material • Wear the recommended PPE • Use appropriate personal hygiene

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