Chapter 4 Gases, Vapors, Particulates, and Toxic Metals

Physical Hazards A chemical that falls into one of the following categories: compressed gas, explosive, flammable gas, oxidizer, pyrophoric, or unstable.

Asphyxiants Simple asphyxiant – gases that displace the oxygen content in the air. Inert gases. Chemical asphyxiant – Gases that prevent cells from using oxygen or prevent the blood from supplying oxygen.

Anesthetic gases – Have a numbing effect and will cause the loss of sensation and unconsciousness. Systemic poisons: Arsine – blood cells and liver Benzene – bone marrow Hydrogen sulfide – respiratory system Mercury – nervous system, kidneys, glands

Health Hazards Carcinogens – are known cancer causers Mutagen – a chemical that is suspected to have the properties required to change or alter the genetic structure of a living cell. Teratogen – a substance that is suspected to have an adverse effect on the development of a human fetus.

Bhopal – Union Carbide A large vapor cloud composed of methyl isocyanate (MIC) escaped. 1,400 people died. This was the first time in modern chemical manufacturing history an event had taken place near a populated area showing how vulnerable a community can be to CPI hazards.

Figure 4-2 Flow Diagram of the Process that Caused the Disaster

Bhopal Mistakes: The vent gas scrubber and flare system was undersized. The refrigeration system was dismantled. Faulty alarms and instrumentation. A jumper line was installed. Stainless steel was not used to save money.

Particulates Small liquid or solid particles dispersed through the air. Various concentrations will have differing effects. Coal dust caused Black Lung.

Dust and Gases Any type of dust can be potentially dangerous if sufficient quantities are inhaled. Two types of respiratory protection programs: air purifying and air supplying.

Dust explosions Occur when particle concentrations are detonated from a single spark. Almost anything will burn if broken down into small enough parts. Dust acts as fuel in Fire Triangle.

Figure 4-5 Examples of Gaseous Hazards

Figure 4-6 Harmful Effects of Toxic Metals

Metallic compounds can be as dangerous as the purer form if not more dangerous depending on how the chemical is introduced into the human system. Class D fires involve fires caused by metals. The proper fire extinguishers must be used for these types of fires.