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Appendix D - Training Program

Chemical Hazards/Fire and Explosion

Objectives/Samples of Behavior:

Comprehend the chemical, fire, and explosion hazards associated with hazardous waste sites.

1. Identify and describe the components necessary in an incident response.

1. Recognition

1. Identifying the substance(s) involved.

2. Identifying the characteristics which determine the substance's degree of hazard.

2. Evaluation

- Determining the impact or risk that the substance poses to response personnel, public health and environment.

3. Control

- Employing methods to eliminate or reduce the impact of the incident.

2. Toxic Hazards

1. Simplistic definition - a chemical that produces an adverse effect.

2. Local effects - inorganic acids.

3. Systemic effects - organic solvents.

4. Examples - benzene, organic pesticides, hydrogen sulfide.

5. DOT labels for toxics:  class 2 and 6, poisons and irritants.

3. Combustion Hazards

1. Terms

1. Combustibility - the ability of material to act as a fuel.

2. Flammability - the ability of a material to generate enough concentration of combustible vapors under normal conditions to be ignited.

3. Fire triangle - must have fuel, oxygen, and ignition source to have a fire.

- Explosive/flammable range:  the LEL/LFL (lower explosive limit/flammable limit) is the lowest concentration of a flammable gas or vapor which will burn in air.

- The UEL/UFL (upper explosive/flammable limit) is the highest concentration of a flammable gas or vapor which will burn in air.  i.e. benzene: 1.3% to 7.1%, n-hexane: 1.1% to 7.5%.

4. Auto-ignition - the minimum temperature at which a substance will ignite in air when there is no ignition source.

5. Flash point - the minimum temperature at which a substance will ignite in air when there is no ignition source.

- Highly flammable - flash point less than 100 degrees F

- Moderately flammable - flash point between 100 and 200 degrees F

- Relatively nonflammable - flash point is greater than 200 degrees F

2. Examples of combustion hazards

1. Flammable liquids

- Aldehydes

- Ketones

- Amines

- Ethers

- Aliphatic and aromatic hydrocarbons

- Alcohols

2. Flammable solids

-Phosphorous

- Magnesium dust

- Zirconium dust

- Titanium dust

- Aluminum dust

- Zinc dust

3. Water reactive flammable solids - potassium, sodium, lithium

4. Pyrophoric liquids

- Organometallic compounds

- Dimethyl zinc

- Tributyl aluminum

3. Combustion hazards summary

1. Most dangerous substances

- Low LEL

- Low ignition temperature

- Wide flammable range

2. Additional Hazards

- Shock wave, heat, flying objects

- Initiation of secondary fires

-  Release of toxic and corrosive compounds

4. Reactive Hazards

1. Chemical incompatability - the combination of two or more reactive materials resulting in uncontrollable, undesirable conditions.  Results include:

1. Heat generation

2. Fire

3. Explosion

4. Formation of toxic vapors

5. Volatilization of toxic or flammable substances

6. Violent polymerization

2. Examples

1. Heat - acid and water

2. Fire - hydrogen sulfide and calcium hypochlorite

3. Explosion - picric acid and sodium hydroxide

4. Toxic vapors - sulfuric acid and plastics

5. Violent polymerization - ammonia and acrylonitrile

*AFOSH Standard 127-68 - charts on chemical incompatibility

3. Chemical reaction rates depend on the following variables:

1. Surface area

2. Physical state

3. Concentration

4. Temperature

5. Pressure

6. Presence of a catalyst

5. Oxidation Hazards

1. Oxidizers - materials that contain large amounts of chemically bound oxygen that is easily released, especially when heated, and will stimulate the burning of combustible material.

1. Hazard features

- React chemically with a large group of substances

- Considerable amount of heat accompanies reaction

2. Oxidizing agents containing oxygen are inherently unstable to heat, decomposing generally by releasing oxygen.

- Destruction of metals and organics

- Ignition of combustible materials

- Organic peroxides may be shock sensitive

3. Examples of oxidizing agents:

- Halogens:  chlorine, fluorine

- Peroxides:  hydrogen peroxide, benzoyl peroxide

- Ozone

- Calcium hypochlorite

6. Corrosion Hazards - polyethylene drums usually good indicator of corrosive materials

1. Corrosion:  chemical degradation of metals due to reaction with the environment, which is accelerated by the presence of acids or bases.  Store in polyethylene drum.

2. pH:  Corrosiveness of acids and bases is rated on the ability to dissociate in solution.  The pH is a logarithmic function of the concentration of hydrogen ions and ranges from 0 to 14, with a pH of 7 being neutral.  Values of pH less than 7 are increasingly more acidic.  Examples:

3. Corrosive hazards - practical considerations

1. Toxicity?

2. Structural damage?

3. Associated damage?

4. Can corrosiveness be monitored?

7. Physical Properties:  physical properties of chemicals help identify and evaluate hazards present in site investigations or operations.  These include:

1. Density/specific gravity - mass per unit volume; usually expressed in grams per cubic centimeter for solids and liquids, grams per liter for gases.  Specific gravity is the ratio of the density of the substance to a reference density.  For liquids, the reference is usually water at 4 degrees C (1 g/cc).

2. Vapor pressure - the pressure exerted by a capor at a given temperature; usually expressed in millimeters of mercury (mm Hg).

3. Solubility - the ability of a solid, liquid, gas, or vapor to dissolve in a solvent.  Usually expressed in ppm or mg/L.  An insoluble substance can be physically mixed or blended in a solvent for a short time but is unchanged when it finally separates.  Solubility is important when determining its reactivity, dispersion, mitigation, and treatment.

8. NFPA 704M

1. The NFPA system uses a diamond divided into four color areas which ranks in the following categories:

1. Red:  Flammability hazard

2. Blue:  Health hazard

3. Yellow:  Reactivity hazard

4. White:  Special information

2. or the red, blue, and yellow areas, a score of 0 to 4 is awarded based on severity, with 0 being negligible and 4 being the most severe.

3. The white special info block may contain a special symbol.  These include symbols for radioactive material as well as:

1. W - water reactive

2. OXY - oxidizer or oxidizing properties

3. COR - corrosive

4. EXP - explosive

5. TOX - toxic

6. IGN - ignitable

4. Examples:

1. Health hazard (blue)

2. Flammability (red)

3. Reactivity (yellow)