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Chemistry

Chemistry. Instructional Goal : upon completion of this topic, the student will have a better understanding of potentially hazardous situations involving corrosives, solvents, oxidizers, and reactive chemicals. Chemical Awareness.

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Chemistry

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  1. Chemistry Instructional Goal: upon completion of this topic, the student will have a better understanding of potentially hazardous situations involving corrosives, solvents, oxidizers, and reactive chemicals.

  2. Chemical Awareness • Hazardous substances are used in business and industry. A basic knowledge of chemical hazard classes, chemical terms, and a basic chemical hazard awareness is required by OSHA.

  3. HAZARD COMMUNICATION STANDARD 29 CFR 1910.1200 The employer’s Haz Com program must include: • Conduct a chemical inventory. • Obtain and file MSDSs for all chemicals. • Label all containers. • Train employees about the hazards. • The Haz Com program must be written and available to employees.

  4. Material Data Safety Sheet • Product ID and manufacturer name • Hazardous ingredients • Physical / chemical characteristics • Fire and explosion hazard data • Reactivity data • Health hazard data • Safe handling and use • Control measures

  5. LABELING • Chemical identity and/or trade name of the hazardous material. • Hazard warning(s). • Name and address of chemical manufacturer.

  6. LABELING NFPA 704 3 4 2 W HMIS

  7. Chemical Awareness • Chemical names and terms can be very confusing and misleading, but can alert a worker to a chemical that has a potential to harm. • Chemical names and hazards must be verified with an MSDS or other such source

  8. Chemical Names with Potential Hazard • aluminum • barium • chlorine • copper • lead • mercury

  9. Word Fragments • -ite • -ate • nitro- • acryl- • chloro- • isocyan-

  10. Corrosive Class Chemicals Corrosives are the second most commonly used and transported group of hazardous materials. A corrosive material is defined as “any liquid that has a severe corrosion rate on steel”.

  11. Corrosive Class Chemicals • bases (caustics) • acids (corrosives)

  12. Corrosives

  13. Chemical Awareness • pH range is from 0 - 14 • Acids • low pH number • high concentration of (H+)ions • Bases • high pH number • low concentration of (H+ )ions

  14. pH Scale

  15. Acid-Base Neutralization

  16. Strong vs Weak Strength of a Corrosive: is the % dissociation of the corrosive when mixed with water. + - HCl100% H & Cl (Strong: 100% dissociation) + - CH3 COOH 2%H & CH3COO + 98% CH3COOH (Weak: only 2% dissociation)

  17. CONCENTRATION • Percent • Molar The amount of material in a given volume of water. The larger the number before the term the more concentrated the solution. 1M soln > 0.1M soln

  18. Strength vs Concentration • strong vs weak • amount of dissociation • concentrated vs dilute • amount of additional solvent (H2O)

  19. Corrosive Hazards • destroy living tissue • chemical burn is 9 times more damaging than a thermal burn • extent of injury from corrosive exposure: • concentration of corrosive • quantity of corrosive • body area affected • duration of contact

  20. Corrosive Hazards • Vapor - far reaching • Inhalation • Liquid • skin/eye contact - splash • Solid • Inhalation of dust • skin/eye contact

  21. Protective Measures • common exposures and protection • hands - gloves • nose, throat, airway - respirator • feet - closed toe shoes • face - faceshield • eyes - goggles or glasses with side-shields

  22. Treatment for Skin Exposure • flush with water: • physically remove corrosive • dilution of corrosive

  23. Hazardous Mixtures • Corrosives and Poisons • release toxic gases • Corrosives and Ignitable Materials • many possible reactions depending on chemicals • some corrosion are oxidizers

  24. Hazardous Mixtures • Corrosives and Water • violent reaction • generation of heat • production of a vapor cloud • over-pressurization of container • Corrosives and Metal • destruction of metal Never store corrosives in a metal container! • production of hydrogen gas HOT

  25. Polychlorinated Biphenyls - PCBs • found in plants, animals, and soil around the world • transported throughout the biosphere by several pathways • suspected human carcinogen

  26. Solvents • halogenated solvents • hydrocarbon solvents that contain one or more halogen atoms (Cl, F, or Br) attached to the hydrocarbon molecule. • flammable solvents • A hydrocarbon solvent having a flashpoint below 100 deg. F. (37.8 deg. C.)

  27. Solvent Hazards • Primary Hazard • Chemical Physical hazard • Secondary hazard • Chemical Health hazard

  28. Fire and Explosion • Oxidizer • Fuel • Ignition source

  29. Acute Health Hazards • Inhalation • Nausea • Headaches and drowsiness • Irritation of mucous membranes of the respiratory passage • Muscular weakness • Loss of coordination • Disorientation and confusion • Unconsciousness and sometimes death

  30. Acute Health Hazards • Skin/eye contact • Removal of skin oils resulting in irritation • Cracking and Rashes on the skin • Dermatitis • Burning and Irritation of eyes

  31. Do’s for Solvents • Read the container label and MSDS before you use the chemical. • Keep the work area clean. Fewer spills happen in clean work areas. • Use protective clothing and equipment when • operating procedures call for them • MSDS recommends it • over-exposures are detected or expected

  32. Do’s for Solvents • Use only approved and labeled containers for storing and transporting solvents. • Make sure there is proper ventilation when using solvents. • Keep flammables away from heat and ignition sources. • Check that containers and hoses are in good working condition.

  33. Don’ts for Solvents • DON'Tleave containers open when not in use. • DON'Tsiphon by mouth. • DON'Tdepend on a "funny smell" to detect hazardous gases in the air - some are odorless. • DON'T breathe gases produced from chemical reactions.

  34. Don’ts for Solvents • DON'Tmix solvents - unless instructed to; follow instructions exactly and double check • DON'Tsmoke, eat or drink around hazardous substances. • DON'T wear contact lenses around toxic vapors. • DON'Ttrack hazardous materials from one location to the next.

  35. Don’ts for Solvents • DON'T store hazardous chemicals next to each other without checking the MSDS for possible reactions. • DON'T work by yourself; have someone nearby who knows where you are and what you're doing at all times. • DON'T cut corners on hazardous substance handling procedures.

  36. Treatment for Solvent Exposure • 15 minute flush at a minimum • wash skin with soap and water

  37. Oxidizers • oxidizing elements • O2, Cl2 • oxysalts • NO3, ClO3 • inorganic peroxides • certain acids • organic peroxides

  38. Hazards of Oxidizers • intensify combustion • spontaneous ignition • explosion • produce toxic fumes • gaseous oxidizers

  39. Water Reactive Metals • lithium • sodium • potassium • beryllium • magnesium • calcium

  40. Unstable Materials • Alkali Metals - Na, K, Li • Organic peroxides - acetyl peroxide, MEK peroxide • Monomers - styrene, vinyl chloride Unstableis defined as any material that will spontaneously decompose, polymerize, or self-react under conditions of shock, temperature, or pressure

  41. Booster Charge Detonator Igniter Main Charge Primer Explosives • igniter • primer • detonator • booster charge • main charge

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