Chemical and Biological Hazards

Transcription

1 Chemical and Biological Hazards

2 Gases and Vapors Gases and vapors are common chemical hazards present in occupational settings. The difference between a gas and a vapor is the state of the chemical at normal temperature and pressure (NTP). A gas is in the gaseous state at NTP. A vapor is in the liquid state at NTP. Understanding the properties of gases and vapors is important for controlling exposures.

3 Gases Some common gases and their vapor pressures and vapor densities are as shown below: Chemical Vapor Pressure (21.1 C) Vapor Density Ammonia 6,658 mm Hg 0.6 Arsine 11,362 mm Hg 2.7 Acetylene 32,838 mm Hg 0.9 Carbon Monoxide 26,600 mm Hg 0.97

4 Vapors Some common vapors and their vapor pressures and vapor densities are as shown below: Chemical Vapor Pressure (21.1 C) Vapor Density Acetone 190 mm Hg 2.0 Benzene 80 mm Hg 2.8 Methyl ethyl ketone 80 mm Hg 2.4 Ethyl Alcohol 65 mm Hg 1.6

5 Non-Volatile Liquids Some common liquids and their vapor pressures and vapor densities are as shown below: Chemical Vapor Pressure (21.1 C) Vapor Density Sulfuric acid mm Hg 3.4 Hydrogen peroxide 17 mm Hg 1.1 Propylene glycol 0.1 mm Hg 2.6 N-Butyl alcohol 9 mm Hg 2.6

6 Aerosols Aerosols are generally produced by some activity at a workplace. An understanding of the properties of the different types of aerosols can help the industrial hygienist in anticipation, recognition, evaluation, and control. The categories of aerosols are as shown below: Dusts Mists Fogs Fibers Smokes Fumes

7 Dusts Dusts are typically generated by an action that disturbs a solid material. Some typical dusts that are present in occupational settings and the source of those dusts are shown in the chart below. Compound How Dust can be Generated Crystalline silica dust (quartz, cristobalite) Cutting granite Grinding sand castings Sand blasting Mining Hard wood dust Woodworking activities Construction projects Coal dust Mining Power generation

8 Mists Mists are typically produced by some action that disturbs a liquid. Some typical mists that are present in occupational settings and the source of those mists are shown in the chart below. Compound How Mist can be Generated Acid mist (sulfuric, nitric, hydrochloric) Steel pickling operations Mineral oil mist (metal working fluids) Metal working Ink mist Printing

9 Fogs Fogs are liquid droplets like mists but with smaller average particle sizes. Fogs are generally formed on purpose to saturate an area with a compound. Some typical fogs that are present in occupational settings and the source of those fogs are shown in the chart below. Compound How Fog can be Generated Methyl bromide Pesticide fumigation Propylene glycol Mineral oil (fog-oil smoke) Artificial fog generation for firefighter training and theatrical productions Fog used for military training exercises

10 Fibers Fibers are particles with a specific length-to-width ratio. Exposures typically occur as a result of disturbing a material. Some typical fibers that are present in occupational settings and the source of those fibers are shown in the chart below. Compound How Fibers can be Generated Asbestos Disturbing building materials Fiberglass Disturbing insulation Synthetic fibers Manufacturing clothing

11 Smokes Smokes are mixtures of liquid and solid aerosols and sometimes vapors and gases. Some typical smokes that are present in occupational settings and the source of those smokes are shown in the chart below. Compound How Smokes can be Generated Tobacco smoke Smoking Biological smoke Laser surgery Diesel exhaust Incomplete combustion

12 Fumes Fumes are small aerosolized particles produced by condensation of an aerosolized solid. Some typical fumes that are present in occupational settings and the source of those fumes are shown in the chart below. Compound How fumes can be Generated Metal fumes Welding Soldering Brazing Asphalt fumes Paving Roofing Paraffin wax fumes Food preparation