1 Company Training Course Session 3: Chemical Hazards at Work.

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Company Training Course

Session 3: Chemical Hazards at Work

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Contents

1. Background

2. Objectives

3. Chemical hazards and risks

4. Relevant hazardous chemicals and their properties

5. Chemical incompatibility

6. Inherent safety approaches to hazard control and basic measures for safe chemical handling

7. Community impacts of accidents with hazardous chemicals

8. Topics for discussion

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Background

• Companies need to understand why some of the chemicals being handled at their operations may be hazardous - explosive, flammable, toxic, corrosive - or harmful in some other way to humans, animals or the environment

• Understanding chemical hazards at work is the first step towards responsible chemical safety management

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Objectives

• To introduce and discuss the concepts of “Hazard” and “Risk”

• To understand the properties of some hazardous chemicals, and on how these can come into contact with the body and cause injury or disease, how they may cause a fire or explosion in the workplace, and how a spill or leak may cause harm to the environment

• To discuss basic measures for safe handling of hazardous chemicals, inherent safety approaches to hazard control, and potential off-site consequences of accidents with hazardous chemicals

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Definition: What is a hazard? • An inherent property of a substance, agent, source of energy or

situation having the potential of causing undesirable consequences. OECD Guiding Principles

• Anything that can cause harm to people and/or environment. GTZ definition

• An inherent chemical or physical characteristic that has the potential for causing damage to people, property, or the environment. It is the combination of a hazardous material, an operating environment, and certain unplanned events that could result in an accident. CCPS

• An inherent physical or chemical characteristic that has the potential for causing harm to people, property, or the environment. CCPS

• A chemical or physical condition that has the potential for causing damage to people, property, or the environment. (CCPS, 1999)

• A chemical, physical, or changing condition that has the potential for causing damage to human life, property, or the environment. CCPS

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Definition: What is a risk?

• Risk is the combination of a consequence and the probability of its occurrence. OECD Guiding Principles

– Consequence is the result of a specific event.

• Risk is the probability that human health, property or the environment will actually be harmed. GTZ definition

• Risk: A measure of potential economic loss, human injury, or environmental damage (cost) in terms of the probability of the loss, injury, or damage over a period of time, normally a year. CCPS

• Risk: A measure of human injury, environmental damage, or economic loss in terms of the incident likelihood and the magnitude of the loss or injury. (CCPS, 2000)

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Hazardous chemicals

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• Hazardous chemicals:– In a broad sense, any chemical or mixture

of chemicals having properties capable of producing adverse effects to the health or safety of human beings or the environment.

– Chemicals presenting dangers that may arise from:• Fires and explosions relating to flash point and

boiling point• Toxicity, reactivity, instability, or corrosivity.

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Physical forms of hazardous chemicals at work

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• The physical form of a chemical can affect:– How it enters the body and to some extent, the

damage it can cause to workers;– Its stability and behavior under average

temperature conditions

• The main physical forms of chemicals are:– Solids– Dusts– Liquids– Vapors– Gases– Aerosols– Fumes

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What are the hazards ?• Physical Hazards:

– Explosives: substances capable by chemical reaction of producing gases at such a temperature and pressure and at such a speed as to cause damage to the surroundings.

– Gases: compressed and liquefied gases– Flammables: combustible substances than ignite at a specific temperature range– Oxidizing substances: substances that by yielding oxygen, can cause or contribute to

the combustion of other materials– Self-reactive substances: thermally unstable liquids or solids liable to undergo a strongly

exothermic thermal decomposition even without participation of oxygen (air).– Pyrophoric substances: substances which, even in small quantities, are liable to ignite

within five minutes after coming into contact with air– Self-heating substances: substances other than pyrophoric substances, which, by

reaction with air and without energy supply, are liable to self-heat– Substances which, in contact with water, emit flammable gases: substances which,

by interaction with water, are liable to become spontaneously flammable or to give off flammable gases in dangerous quantities

– Corrosive substances

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What are the hazards ?• Health Hazards:

– Acute Toxicity: substances are assigned to one of the five toxicity categories on the basis of LD50 (oral, dermal) or LC50 (inhalation)

– Skin Corrosion/Irritation: means the production of irreversible/ reversible damage to the skin following the application of a test substance for up to 4 hours

– Serous Eye Damage/Eye Irritation: means the production of tissue damage/changes following application of a test substance to the front surface of the eye, which is not fully reversible within 21 days of application

– Respiratory Sensitization: substances that induces hypersensitivity of the airways following inhalation

– Skin Sensitization: substances that will induce an allergic response following skin contact– Germ Cell Mutagenicity: agents giving rise to an increased occurrence of mutations in

populations of cells and/or organisms– Carcinogenicity: substances which induce cancer or increase its incidence

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What are the hazards ?• Health Hazards (continued):

– Reproductive Toxicology: substances that may have adverse effects on sexual function and fertility in adult males and females, as well as developmental toxicity in offspring

– Target Organ Systemic Toxicity – Single Exposure

– Target Organ Systemic Toxicity – Repeated Exposure

– Aspiration Toxicity: substances that may have acute effects such as chemical pneumonia, varying degrees of pulmonary injury or death following aspiration

• Environmental Hazards:– Hazardous to the Aquatic Environment – Acute Water Toxicity:

means the intrinsic property of a material to cause injury to an aquatic organism in a short-term exposure

– Hazardous to the Aquatic Environment – Chronic Aquatic Toxicity: means the potential or actual properties of a material to cause adverse effects to aquatic organisms during exposures that are determined in relation to the lifecycle of the organism

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Possible effects of hazardous chemicals

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• Fire and explosions:– Explosive substances (e.g.: ammonium nitrate)

– Flammable substances (e.g.: solvents like Isopropanol)

– Oxidizing substances (e.g.: Potassium permanganate)

– Organic peroxides (e.g.: Dibenzoyl peroxide

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• Health hazards:– Toxic substances (e.g.: Dimethyl sulphate)

– Harmful substances (e.g.: Disodium disulfit)

– Corrosive substances (e.g.: Sulphuric acid)

– Irritating substances (e.g.: 3,7-Dichlorchinolin-8-carbon acid)

– Carcinogenic substances (e.g.: 2,3-Dinitrotoluol)

– Mutagenic substances (e.g.: 2,3-Dinitrotoluol)

– Reproduction toxicity substances (e.g.: 2,3-Dinitrotoluol)

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Possible effects of hazardous chemicals

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• Pollution of the environment– Environmentally hazardous substances (e.g.: Ethyl-2-

cyclohexylpropionate)

• Destruction of material– Corrosive substances (e.g.: Hydrofluoric acid)

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Do you know…

• …which chemical substances being handled in your company are explosive? How are these being handled?

• …if you are storing or using compressed and liquefied gases in your company? How are these being used?

• …which chemical substances being handled in your company are flammable? How are these being handled?

• …which chemical substances being handled in your company are considered as oxidizing substances? How are these being handled?

• …which chemical substances being handled in your company are self-reactive substances? How are these being handled?

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Health risks due to unsafe and accidental exposure

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• Effects can be acute or chronic depending on the concentration and length of exposure.– Irritation (skin, eyes, respiratory tract)– Allergies– Lack of oxygen (from sensation of being drunk to death)– Systemic poisoning– Cancer– Damage to the unborn fetus, including during the first three

months of pregnancy– Effects on the future generation– Pneumoconiosis (dusty lung)

• Routes of exposure (Inhalation; Ingestion; Absorption; Injection)

• Symptoms of possible overexposure (Eye discomfort; Breathing difficulty; Dizziness; Headache; Nausea; Vomiting; Skin irritation)

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Relevant hazardous chemicals and their properties

• LPG (generic name for commercial propane and commercial butane)

i. If an LPG vessel is involved in a fire or if a major rupture occurs, for example due to vehicle impact, a fireball can result

(In 1990, an explosion was caused by an LPG-containing truck accident in Bangkok which resulted in 63 people killed, and 90 injured)

ii. An LPG cylinder or tank, if involved in a fire, has the potential to undergo a BLEVE (boiling liquid expanding vapour explosion), causing a large fireball and multiple fatalities in the vicinity

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• LPG (continued)

iii. Such scenarios are common to most industrial premises and, utilizing relevant good practice, the risk is suitably low.

Such good practice includes:– Segregation of LPG storage from combustibles and other

dangerous substances;– Burner controls which isolate the fuel if ignition is lost;– Inspection programmes for pressure vessels and piping;– Protection of vessels and piping from impact.

(further guidance on LPG can be found at “Use of LPG in small bulk tanks” and “Small-scale use of LPG in cylinders”, HSE)

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• Ammonia (NH3, it is normally as a gas with a characteristic pungent odor, and in solutions)

i. Ammonia used for agricultural applications (like fertilizers), refrigeration (primarily food production and storage), metallurgical applications, and medical applications

ii. Ammonia is Highly Toxic due to its corrosive effects (Ammonia vapor primarily affects the mouth and upper airway, trachea, lungs, skin and eyes)

iii. Ammonia is highly hazardous to the environment

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• Ammonia (continued)

iv. Some accidents involving the transportation of ammonia:

– 21 January 1997 (INDIA, Bhopal): Ammonia leakage during transportation resulted in 400 people injured;

– 12 March 1995 (INDIA, Maharashtra): transport accident involving Ammonia gas resulted in 2000 people injured;

– October 1991 (INDIA, New Bombay): transport accident involving ammonia gas resulted in 1 death and 150 injured

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• Chlorinei. Chlorine gas is used in making plastics, solvents

for dry cleaning and metal degreasing, textiles, agrochemicals and pharmaceuticals, insecticides, dyestuffs, etc. It is also an important chemical used for water purification, in disinfectants, and in bleach

ii. Chlorine is a toxic gas that irritates the respiratory system. Because it is heavier than air, it tends to accumulate at the bottom of poorly ventilated spaces. Chlorine gas is a strong oxidizer, which may react with flammable materials, and metals.

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• Chlorine

iii. ABC Dry Chemical should never be used to fight a chlorine fire, as the resulting chemical reaction with the ammonium phosphate would release toxic gases and/or result in an explosion

iv. Chlorine gas reacts with the moisture in mucous membranes, such as eyes and the respiratory tract, to create acid, which burns the skin, and in sufficient concentration, can destroy the respiratory system after only a few breaths.

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• Chlorine

v. Some accidents involving the release of chlorine gas:

– January, 1997 (PAKISTAN, Lahore): transportation accident involving the release of Chlorine resulted in 32 deaths, 900 people injured, and 1000 people evacuated

– April, 1994 (INDIA, Thane District): transportation accident involving the release of Chlorine gas resulted in 4 deaths and 298 people injured

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• Acrylonitrilei. Acrylonitrile is an important monomer for the

manufacture of useful plastics. It is used:– as a raw material for the production of synthetic

fibers, plastics and synthetic rubber;– as a raw material for acrylic acid, acrylic esters, and

acrylic amide;– in the synthesis of compounds used for the

production of adhesives, anti-oxidants, binders for dyestuffs and emulsifiers.

ii. Overexposure to acrylonitrile: headache, sleeplessness, nausea, vomiting, diarrhea, fatigue, and irritation and inflammation of the eyes and respiratory tract. In more severe cases, unconsciousness and convulsions

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• Acrylonitrile (continued)

iii. Exposure should be avoided by use of adequate ventilation and proper Personal Protective Equipment (PPE)

iv. Acrylonitrile is highly flammable and toxic. It undergoes explosive polymerization. The burning material releases fumes of hydrogen cyanide and oxides of nitrogen. Acrylonitrile is classified as a recognized human carcinogen

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• Acrylonitrile (continued)

v. Some good practices in the use of Acrylonitrile (not exhaustive):

• Do not use the compound near sources of ignition.• Do not use compressed air for filling, discharging, or

handling.• In case of fire, keep drums cool by spraying with

water• Fire fighters should use self-contained breathing

apparatus

vi. Well-known accidents involving Acrylonitrile include the 2001 accident in Thailand where a truck had an accident on an express way in Bangkok releasing Acrylonitrile onto the road and drainage

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• Dimethyl sulfate (DMS)

iii. DMS is a versatile chemical that can be used for a variety of processes in the production of many household and commercial chemicals. It is a strong methylating agent that reacts with active hydrogen and alkali metal salts to form substituted oxygen, nitrogen, and sulfur compounds

iv. Dimethyl sulfate is used:– as a reagent for the methylation of phenols, amines, and thiols

– particularly in the dye industry and in the manufacture of organic chemicals, such as fabric softeners, and of pharmaceuticals

v. Very toxic, and may be fatal, if inhaled. DMS is likely carcinogenic and mutagenic, poisonous, corrosive, environmentally hazardous and volatile (inhalation hazard). May act as a sensitizer. May cause reproductive damage. Considered a potential chemical weapon.

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• Dimethyl sulfate (DMS)

iv.DMS is absorbed through the skin, mucous membranes, and gastrointestinal tract. Lachrymator. Very destructive of mucous membranes. Toxicity is manifested initially by mucosal inflammation of eyes, nose, oropharynx, and airways

v. Well known accidents involving Dimethyl sulfate include a gas leak that followed an eight-car crash on an expressway in central China that resulted in the rupture of a gas tank, leaving five dead and more than 50 sick. The chain of collisions ruptured a tanker carrying 27 tonnes of toxic dimethyl sulfate gas. The gas leak irritated the eyes, throat and skin of police, firemen and nearby villagers as well as the motorists.

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• Toluene Diisocyanate (TDI)

iii. TDI is a synthetic organic chemical used in the production of polyurethanes for flexible foam applications. TDI-based polyurethane foams are widely used in the automotive and furniture industries, and in packaging and insulation

iv. TDI is a toxic compound, and it should be treated as both a potential human carcinogen and as a known animal carcinogen. Exposure can lead to adverse effects on the respiratory tract, skin, eyes, and gastrointestinal tract.

v. Well known accidents involving TDI include the Hebei Chemical Factory Blast in China in 2007. The company is one of the major TDI producers in China. Following an explosion in a nitration workshop that lead to the death of five workers, more than 2,000 residents in the village were evacuated for fear of possible toxic gas leak.

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• Organic solvents (benzene, toluene, trichloroethylene, ethyl

alcohol, methyl alcohol, acetone, dichloromethane, chloroform, etc)

iii. Solvents are substances which are used to dissolve or dilute other substances. Industrial solvents are often mixtures of several individual substances and they can be found under a variety of trade names.

iv. Some of the short-term health effects of exposure to solvents include:

– irritation of eyes, lungs and skin;

– headache;

– nausea;

– dizziness; and

– light-headedness.

v. Unconsciousness and even death can result from exposure to very high concentrations of solvent vapours.

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• Organic solvents (continued)

iv. Amongst the most hazardous solvents are benzene, carbon disulphide and carbon tetrachloride

v. Most organic solvents are flammable or highly flammable, depending on their volatility. Exceptions are some chlorinated solvents like dichloromethane and chloroform. Mixtures of solvent vapors and air can explode.

vi. Some solvents produce vapors which are heavier than air. These may move on the floor or ground to a distant ignition source, such as a spark from welding or caused by static electricity.

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• Organic solvents (continued)

vii. Some good practices in the use of solvents (not exhaustive):– The solvents which pose the most serious risk to health should

be substituted by less hazardous ones.

– If this is not possible, at least the conditions during handling should be adjusted so that there is no risk of skin contact and that the concentration of vapor in the air is kept low.

– Ventilation is important and it should be considered carefully when using solvents.

– Equipment (fire extinguishers, absorbent material, etc.) should be considered and provided for situations such as spillage or emergency.

– Personal protective equipment such as aprons, gloves and masks with filters should be available where needed, and they should be used according to the recommendations.

– Storage of this equipment should be in a clean place away from possible contact with solvent vapors.

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• Organic powders

iii. Organic powders are often present in the manufacturing of plastics, rubber, pesticides, pharmaceuticals, dyes, etc.

iv. Most organic powders are toxic (breathing exposure)

v. Dust explosions can occur when fine materials are disbursed to a certain concentration and an effective ignition source is present. If dust deposits around premises form a cloud an initial small explosion is often followed by a much larger one

vi. Some ignition control measures:– Use appropriate electrical equipment and wiring methods;

– Control static electricity, including bonding of equipment to ground;

– Control smoking, open flames, and sparks;

– Control mechanical sparks and friction;

– Use separator devices to remove foreign materials capable of igniting combustibles from process materials;

– Separate heated surfaces and heating systems from dusts.

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Chemical incompatibility

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• Incompatible chemicals:– Flammables and oxidizers– Flammables and any ignition source– Acids and cyanides– Strong acids and strong alkalines– Concentrated acids and water– Organic solvents and corrosives– Corrosives and other reactive materials

• Some inadvertent chemical reactions which may produce toxic gases:

– Cyanide + acid produces hydrogen cyanide (HCN)– Hypochlorite + acid produces chlorine

– Bifluoride + acid produces hydrogen fluoride (HF)8

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Inherent Safety approaches to hazard control at source

• The Inherently Safer Design concept was firstly presented by Trevor Kletz in the late 1970s as a fundamental approach to hazard/risk management which focused on avoiding or limiting hazards at source, rather than relying on add-on safety features or management systems and procedures to control them

• Inherent safety: a proactive method that can be incorporated at any stage of design and operation of the plant in the chemical process industries. However, its application at the earliest possible design stages yields the best results.

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Inherently Safer Production

• Minimize: lower as much as you can the quantity of the hazardous chemicals being used

• Substitute: replace dangerous chemicals by a less harmful ones, if possible

• Simplify: revise the process / handling / transport to make it simpler

• Moderate: change the process or the form of the chemical product to be less harmful

• Improve logistics and layout: revise the layout of the plant for transport to be less risky. Move hotspots to a greater distance from buildings

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Inherently Safer Production Checklist

• Minimize: lower as much as you can the quantity of the hazardous chemicals being used

– Is there a specific quantity of a dangerous (especially toxic, explosive, flammable, reactive) chemical raw materials, products or intermediates (in storage or process) that could potentially cause a major accident?

– Are there options to reduce that quantity? (e.g. by changes in procurement policy, storage in smaller units, by combining production and use on site, or by process intensification)

• Substitute: replace dangerous chemicals by a less harmful ones, if possible

– Is it possible to replace the most dangerous chemical(s) product by a less dangerous material?

– Can suppliers provide more benign alternatives?

– Are there alternatives for the most dangerous processes? (e.g. can the process be substituted by another process that is less dangerous?)

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• Simplify: revise the process / handling / transport to make it simpler

– Is it possible to redesign the process or the handling or transport of chemical materials to reduce the complexity and foster simplicity?

• Moderate: change the process or the form of the chemical product to be less harmful

– Is it possible to change the process or the form of the chemical products so they are less harmful? (e.g. lower concentration or using pills instead of powders)

– Can a (bio) catalyst help to process chemicals at lower temperatures and pressures, approaching ambient conditions?

– Are there activities whereby chemical products are used in open air?

– Can these activities be changed so that the chemicals are contained?

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• Improve logistics and layout: revise the layout of the plant for transport to be less risky. Move hotspots to a greater distance from buildings

– Can the lay-out of the facility be changed so that transport of chemical products becomes simpler and less risky? (supply, transit, transport of products, removal of wastes)

– Can hot spots of chemical hazards be removed to greater distances from buildings or other places were many people come and go?

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Never eating/drinking/smoking while using hazardous chemicals Using always the appropriate Personal Protective equipment (PPE) Labeling and identification of hazardous chemicals Never smelling or tasting a chemical as a means to identify it Safe storage of hazardous chemicals Containment and drip trays where spills may be expected Availability of Material Safety Data Sheets (MSDS) and chemical

risk information at work Keeping containers closed when not in use Keeping flammable chemicals away from ignition sources Avoiding contact between incompatible materials Earthing/grounding systems Not using improvised containers, hoses, pipes, or vessels Proper management of change Cleaning up spills, proper waste disposal and good housekeeping

Basic measures for safe chemical handling

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Community impacts of accidents with hazardous chemicals

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China, Natural Gas Drilling Blast2003 - 243 deaths, 9,000 injuries

and 64,000 evacuated

Algeria, explosion, Natural Gas Plant

2004 - 38 deaths, 74 injuries

Ammonium Nitrate Train Explosion – North Korea – 2004

- 161 deaths, 1300 injuries

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Topics for discussion…

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• Importance of understanding the properties of hazardous chemicals

• Potential health effects of exposure to hazardous chemicals

• Environmental effects of accidents with hazardous chemicals

• Fire protection and explosion hazards

• First steps that could be taken towards risk reduction at site

• Potential effects of an accident involving hazardous chemicals in the communities located in the vicinity of their companies’ operations

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Contacts

1 Company Training Course Session 3: Chemical Hazards at Work.

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