Hazard ID and Properties of Hazardous Substances

1. Hazard ID and Properties of Hazardous Substances Heritage Group Safety HAZWOPER Training

2. Introduction • In a response situation personnel may be exposed to a number of hazardous substances because of their chemical characteristics and physical properties. • Basic knowledge of these characteristics and properties is paramount to personal safety.

3. Topics of Discussion • In Chapter 2 of Manual • Hazardous Substances • Physical Properties of Chemicals

4. BIOLOGICAL HAZARDS • The Five Biological Agents which can cause infection or disease in humans. • What are they? • Like chemical hazards Biological Hazards can be dispersed via air and water. • Protection against these hazards is the same as for chemical hazards.

5. RADIATION HAZARDS • The three types of Radiation: Alpha, Beta and Gamma • Alpha and Beta are particle radiation while Gamma is wave radiations • All are referred to as IONIZING Radiation and can upset human cellular function

6. Alpha and Beta • The Alpha is positively charged + • The Beta is negatively charged - • Both are normally repelled by clothing or skin. They are dangerous when they enter the body through ingestion or inhalation.

7. CHEMICAL HAZARDS • Fire Hazards • Explosive Hazards • Toxic Hazards • Corrosive Hazards • Chemical Reactivity • Physical Properties

8. Fire Hazards • Combustibility • Flammability • Pyrophorics • Gas or Vapor Explosions

9. Combustibility • The ability of a material to act as a fuel • OSHA says combustibles have flash point between 100° F and 200° F • Anything that can be readily ignited and sustain a fire • Anything that can’t is considered non-combustible

10. The Fire Triangle FUEL HEAT OXYGEN

11. Flammability • The ability of a material (gas or liquid) to produce sufficient vapors to be ignited and produce a flame under normal conditions. • There must be a proper fuel to air mixture to sustain combustion. Each material has its own mixture range called “Flammable Range”.

12. UFL and LFL • Concentrations < the LFL will not burn because they are too “lean”. • Concentrations > the UFL will not burn because they are too “rich”.

13. OSHA FLAMMABLE • OSHA considers anything flammable if it has a flash point below 100°F. • Flashpoint - See Section 2, page 14.

14. REGULATORY CONFUSION • OSHA-Flammable: < 100°F Combustible: 100F-200°F Will Not Burn: > 200°F • DOT- Flammable: < 141°F Combustible: > 141°F but < 200°F Non-Hazardous: Anything > 200°F • EPA- Anything < 140°F is “Ignitable”

15. GAS OR VAPOR EXPLOSIONS • A Rapid, Violent Release of Energy • Large amounts of kinetic energy, heat and gaseous products are released. • The KEY is confinement of a Flammable Material. The combustion reaction is more rapid and confinement increases energy which enhances the explosive process.

16. UEL and LEL • Explosive gases and vapors exhibit an explosive range which is the same as the flammable range. • The UEL (Upper Explosive Limit) and the LEL (Lower Explosive Limit) are the same as UFL and LFL, but in confined areas. • Again, CONFINEMENT is the Key!

17. EXPLOSIVE HAZARDS • An Explosive is a substance which undergoes very rapid chemical transformation producing large amounts of gases and heat. • Because of the heat the gases expand at velocities exceeding the speed of sound which in turn produces a shock wave and noise.

18. Types of Explosive Hazards • High or Detonating- Very rapid chemical transformation with detonation rates as high as four miles per second: 1. Primary High Explosive 2. Secondary High Explosive • Low or Deflagrating- Deflagration rate up to 1,000 feet per second.

19. Detonating vs Deflagrating • In a Detonation rapidly expanding gases produce a shock wave which may be followed by combustion. • In a Deflagration combustion is generally followed by a shock wave. (See examples in Section , page 8) WHAT ARE THE PRACTICAL CONSIDERATIONS?

20. TOXIC HAZARDS • Toxic hazards cause either a local or systemic effect on an organism and while death is not always certain it is an immediate concern. • Types of toxic hazards are classified as to their physiological effect on the organism: poisoning, asphyxiation, sensitization, and carcinogenicity are a few.

21. Dose - Response • Toxic effects on human beings depends on the length and amount of exposure and the level of toxicity (its lethal dose) of the material. HAZARD = EXPOSURE + TOXICITY • Therefore, as the dose (length of exposure and amount of exposure) increases the human response increases also.

22. CORROSIVE HAZARDS • Corrosion is the process of material degradation. Corrosive materials may destroy human tissue, metals, plastics and other materials. • Common corrosives are halogens, acids and bases. Skin irritation and possible irreversible tissue destruction are possible with exposure to corrosives.

23. Acids, Bases and pH • Materials that form the greatest number of hydrogen ions (H+) are the strongest acids. Those that form the most hydroxide ions (OH-) are the strongest bases. • The H+ ion concentration in solution is called pH. Therefore, strong acids have a low pH and strong bases have a high pH (fewer H+ ions) See pH scale on page 2-9.

24. CHEMICAL REACTIVITY • Reactivity Hazards- a chemical which undergoes a violent reaction with water or under normal ambient temperatures. (Pyrophoric liquids and water- reactive flammable solids).

25. Chemical Reactions • A Chemical Reaction is the interaction of two or more substances, resulting in chemical changes. • Exothermic, which give off heat, can be the most dangerous. • Endothermic reactions require a separate heat source to continue the reaction.

26. Compatibility • When two or more hazardous materials remain in contact with each other indefinitely they are compatible. • On a waste clean-up site any number of instances where chemicals may be mixed are possible. One must know if such materials are compatible. If they are not, reactions may range from explosion to gas release.

27. Compatibility • See examples in Section 2, page12. • WHAT ARE THE PRACTICAL CONSIDERATIONS?

28. IT’S MOVIE TIME! • “Introduction to Hazardous Chemicals” • The Emergency Film Group, Plymouth, MA • 508-746-0466

29. PHYSICAL PROPERTIES OF CHEMICALS • One of the most ignored parts of an MSDS is the part where Physical Properties ofChemicals are listed. • Most people do not understand Physical Properties. • Evaluating risk on an incident depends on understanding these properties.

30. Solubility/Miscibility • The amount of chemical (solid, liquid, gas or vapor) which can be dissolved in water at 68°F. Measured in percent, the higher the percentage, the more chemical that will dissolve in water. • Example: Sugar is 100% soluable. • Miscibility refers, specifically, to the solubility of a liquid.

31. Density and Specific Gravity • The Density of a substance is its mass per unit volume, commonly expressed in grams per cubic centimeter (g/cc). • The density of water is 1 g/cc. • Specific Gravity is the density of a chemical compared to that of water. If the SpG is less than 1g/cc the chemical will float. If SpG is more than 1 g/cc it will sink.

32. Vapor Density • The Density of a gas or vapor can be compared to the ambient atmosphere. If the density of a vapor or gas is greater than ambient air, it will tend to settle. • If Vapor Density is close to, or less than, ambient air it will rise or disperse in the atmosphere. • Discuss hazards page 2-13.

33. Vapor Density, continued • What are the hazards of a gas or vapor which will settle? Use Carbon Monoxide as an example. • How about Gasoline vapors?

34. Vapor Pressure • Pressure exerted, by a vapor, on the sides of a closed container. • It is Temperature Dependent. As temperature increases, so does Vapor Pressure. • The lower the boiling point of a liquid, the greater vapor pressure it will exert at a given temperature.

35. Vapor Pressure, continued • Values for Vapor Pressure are most often given as millimeters of mercury (mm Hg). • NIOSH Handbook • Examples: Ammonia- VP= 8.5 atm (p. 262) Carbon Monoxide (p. 54) Methyl hydrazine (p. 210) Atmospheric Pressure - 760 mm Hg.

36. Boiling Point • Temperature at which liquid changes to vapor. The temperature where the pressure of the liquid equals atmospheric pressure (760 mm Hg). • What it the boiling point of Ammonia? • What is the boiling point of Sulfuric Acid? • What is the route of entry for each of these?

37. Melting Point • Temperature at which a solid changes to a liquid. It is also the freezing point-depends on the direction of the change. • Example: Water (ice) = 32°F

38. Flash Point • The minimum temperature at which a substance produces sufficient flammable vapors to ignite: • Highly Flammable • Moderately Flammable • Relatively Inflammable

39. Odor Threshold • The minimum concentration of a substance in air that can be detected by the human sense of smell. • It is different for each person. Ammonia= 5 ppm Ethyl alcohol= 10 ppm • The ACGIH STEL for Ammonia 25 ppm. What does this mean?

40. IDENTIFYING HAZARDS Knowledge of the Hazards of various substance and an understanding of Physical Properties can be the difference between life and death.