Chemical Hazards/

Safety

Chemical 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

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/Hazards

Chemical forms

Liquids, Solid, Dust, Fume, Mist, Vapour & gas

Modes of Entry

Injection, Skin Absorption/eyes, Inhalation

Toxicity

Ability 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.

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.

LiquidsFor example,

• inhalation is the primary route for a chemical to enter the body. Its vapor 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.

Health Hazards

1. Irritant

2. Toxic Effect

3. Asphyxiant

4. Teratogenic (unborn child)

5. Mutagenic (Heritable genetic defects)

6. Oil Acne (Cutting Oil)

7. Particle size (Micron) ≤10 ≤100

8. Photosensitiser (Irritant or Sensitizer + UV)

Coal Tar Pitch.

Exposure Route

Lung

Ear EyeNoseMouth

Musculo-

skeletal

SkinWhole body

Target Organs

Lung Heart

Digestive tractLiver

Kidneys

Ear

Eye

Skin

NoseMouth

Reproductive

system

CNSCentral Nervous System

Personal Protective Equipment

1. Depends;- Physical Form, (Solid, Gas, Liquid)

2. Potential health effects (Irritancy - Toxicity)

3. Quality handled

4. Method used

5. Hazard Labelling

6. Break Through Period

Types = Protective Clothing, Gloves, Goggles,

Shields

Hearing Protection, Respirator -

Air Supplied

Air Purified

Control Measures

•Elimination

•Substitution

•Changed Method of work

•Engineering Control (extraction)

•Information, Instruction & Training

•Personal Protection Equipment

•Monitoring

•Recovery Measures (Emergency

Plan)

National Fire Protection Association

Hazard Classification

0

W

2

4

Flamability

Reactivity

(Stability)

Health

Water