Chemical Handling/Hazards

Chemical hazards

– Chemicals are the most common and significant health hazards

– Chemicals can be hazardous for numerous reasons and can combine with other chemicals to make new hazards

– All hazards must be taken into account when using and storing chemicals.

Objectives • To:

– Recognize chemical hazards commonly encountered in the field

– Explain warning properties of various chemical hazards

– Describe how to evaluate and control these hazards.

• The degree of hazard associated with a particular chemical will depend on:

– Its physical properties – Its toxicity – The way it is used – The environment in which it

is encountered.

Chemical Handling/HazardsChemical hazardsLiquids, Dust, Fume, Mist, Vapour & gas

Modes of EntryIngestionSkin Absorption/eyesInhalation

ToxicityAbility of the substance to harm the body and the manner in which it harms the body

Quantity + Duration + Toxicity = Dose

The dose makes the poison

Physical Classification

Solids Aerosols

Liquids Vapours

Chemicals may be found in solid, liquid, aerosol, or gas and vapor form.

The degree of danger varies according to the form of the chemical and the factors previously discussed.

Solids • Not all forms of a chemical pose

a health hazard. • For example, a lead pipe is not a

significant health hazard. • However, the lead can become a

human health hazard if the pipe is sanded or welded, producing lead dust or fumes.

• The dust or fumes can become airborne and be inhaled, or it can leach into water and be ingested.

Solids • A chemical may be hazardous even in

solid form. • For example, individuals who are

sensitized to nickel may develop dermatitis from skin contact with the metal.

• Fuming solids emit toxic vapors that may be inhaled.

• Some materials, such as pesticides, can evaporate directly from solid form.

• Some solids are not a hazard alone but become hazardous when they come into contact with other chemicals (e.g., acid in contact with iron can release hydrogen gas).

Aerosols• Aerosol is a term used to describe

fine particles (solid or liquid) suspended in air.

• Examples of aerosols include dust, fumes, mist, fog, smoke, and smog.

• Knowing how various aerosols are generated will help you anticipate where aerosol hazards may exist in the field

• Aerosols may be a hazard to the eyes, skin, and the respiratory system.

Liquids• Many liquids are hazardous in

contact with the skin. They either damage the skin or they are easily absorbed through the skin.

• chemicals that can damage or be

absorbed through the skin and will have this effect on all skin, not just the hands.

• The degree of hazard associated with a liquid depends on its characteristics and how it is handled.

LiquidsFor example,• inhalation is the primary route for a

chemical to enter the body. Its vapour pressure is important in determining the liquid’s degree of hazard.

• Liquids with a low vapor pressure may create a low airborne concentration.

• Liquids with a high vapor pressure may produce high airborne concentrations.

• The hazard level of an airborne concentration depends in part on the chemical's toxicity.

ToxicityToxicity Depends on : Amount + Duration

Exp

osur

e or

eff

ect

Dose

Res

pons

e of

% d

ead

LD50 LC50(other routes)- (air)Dose (single exposure)

50

Health Hazards1. Irritant Severe Irritation

IrritationSlight or No effect

2. Toxic Effect High LD50 ≤100ppm3. Asphyxiant4. Sensitiser5. Teratogenic (unborn child)6. Mutagenic (Heritable genetic defects)8. Carcinogenic9. Oil Acne (Cutting Oil)10. Particle size (Micron) ≤10 ≤10011. Photosensitiser (Irritant or Sensitiser + UV) Coal Tar Pitch11.

Exposure Route

Lung

Ear EyeNoseMouth

Musculo-skeletal

Skin Whole body

Target Organs

Lung Heart

Digestive tractLiver

Kidneys

EarEye

Skin

NoseMouth

Reproductive system

CNS

Personal Protective Equipment•Depends; Physical Form, (Solid, Gas, Liquid)•Potential health effects (Irritancy - Toxicity)•Quantity handled•Method used•Nominal Protection Factor•Hazard Labelling•Break Through Period

Types =Protective ClothingGlovesGogglesShieldsHearing ProtectionRespirator - Air Supplied

Air Purified

Control Measures

•Chemical Approval PanelMSDS (SHOC)•Elimination•Substitution•Changed Method of work•Engineering Control (extraction)•Information, Instruction & Training•Personal Protection Equipment•Monitoring •Recovery Measures (Emergency Plan)

National Fire Protection AssociationHazard Classification

0

W

2

4

Flamability

Reactivity(Stability)

Health

Water