CHEMICAL HAZARDS

Chemical hazards

• Hazard: Any situation that has potential/capability to cause Injury/harm to the worker, damage to the property, Loss/contamination to the environment.

• Risk: Any situation that has probability to cause Injury/harm to the human, damage to the property, Loss/ contamination to the environment.

Chemical hazards

• Accidents: These are unplanned, unwanted and improper occurrence involving injury/harm to the employee, damage to the property, Loss/contamination to the environment.

Chemical hazards

Types of Chemical Hazards

Irritant chemicals

Sensitizers

Toxic Chemicals

Asphyxiates

Anesthetic and Narcotic

Systematic poisons

Chemical hazards

• Respiratory fibro gens

• Carcinogens

Chemical hazards

• Irritant chemical: Primary irritant cause inflammation is one of the body’s defense mechanisms. It is the reaction of tissue to harm which in sufficient to kill the tissue and is typified by construction of the small vessels in the affected area, dilution of the blood vessels, increased permeability of vessel walls, and migration of the white blood cell and defensive cells to the invading harmful chemicals i.e. sulphur dioxide may made a blistering effect on Upper respiratory.

Chemical hazards

• Sensitizers: generally sensitizers may not on first contact result in any ill effects, although cellular changes can be induced and the body’s immune system affected (some chemicals may act as primary irritants as well as sensitizers).

Chemical hazards

• Anesthetic and Narcotic: anesthetic and narcotic e.g. hydrocarbons and certain derivatives such as the various chlorinated solvents or other, exert a depressant action on the central nervous system i.e. Aliphatic alcohols, petroleum etc.

Chemical hazards • Systematic poisons: Systematic poisons attack

organs other than the initial site of contact. The critical organs are the kidneys, liver, blood and bone marrow. Many halogenated hydrocarbons are effects the Visceral organs in Hematopoietic (i.e. blood-forming system) Nervous system.

Chemical hazards

• Respiratory fibro gens: The hazard of particulate matter is influenced by the toxic and size and morphology of the particles. The critical size of dust (and aerosol) particles is 0.5 to 7 µm, since these can become deposited in the respiratory bronchioles and alveoli. i.e. Free crystalline silica.

Chemical hazards

• Carcinogens: Cancer is a disorder of the body’s control of the growth of cells. The diseases may be a genetic or influenced by life style or exposure to certain chemicals, termed carcinogens i.e. Coal tar pitch dust, Asbestos etc.

Chemical hazards

• Toxic Chemicals: Chemicals having following values of acute toxicity and which, owing to their physical and chemical property, are capable of producing major accidents hazards.

Chemical hazards

• TOXICITY: IDLH: the Immediately Dangerous to Life and Health are not occupational exposure limits similar to the TLV. They were developed by National Institute of Occupational Safety and Health to guide respirators selection. It is that maximum level of concentration of an air borne contamination from which one could escape within 30 minutes without any impairing symptoms or any irreversible health effects. It is reported in ppm or mg/m3.

Chemical hazards

• TLV (THRESHOLD LIMIT VALUES): The two or more

hazardous substances are present, their combined effect rather than that of individually, should be given primary consideration. The effects of the different hazards should be consideration as additive.

• Time-Weighted Average: The TLV may be a Time-Weighted Average (TWA) figure that would be acceptable for 8 hours exposure. For some substances such as an extremely irritating one, a Time weighted Average concentration would not be acceptable.

Chemical hazards

• TLV-STEL: Some substances have a Short-Term Exposure Limit. The 8 hours TLV remains within the limit. Such limits were assigned to substances exerting toxic even over a short period of time. STEL exposure should not be more than 4 per day with at least 60 minutes gap between successive exposures.

Chemical hazards

• LTEL (Long-Term Exposure Limit): Long-term exposure limit are concerned with the total intake of contaminants (or contaminants) over a long period.

• LD 50 for acute local Toxicity: It is that dose of the substance administered which is most likely to cause death within in one half of both male and female young adult rats. The result is expressed in mg per kg body weight.

Chemical hazards

• LC 50 for acute toxicity in Inhalation: It is that concentration of vapor, mist, or dust which, administered by continuous inhalation to both male and female young adult rat for one hour causes death within 14 days in one half of the animals tested.

• LC Lo (Lethal Concentration Low): It is the lowest concentration of a substance in air other than LC50 which has been reported to have caused death in humans and animals.

Chemical hazards

• LOWER EXPLOSIVE LIMIT: The maximum concentration of a gas, vapor, mist or dust in air at a given pressure and temperature that will propagate a flame when exposed to an efficient ignition source. Generally expressed as % by volume for gases and vapors, and as mg/m3 for mists or dusts.

• MAXIMUM EXPOSURE LIMIT: The maximum concentration of an airborne sub-stance, averaged over a reference period, to which employees may be exposed by inhalation under any circumstance. Thus, exposure to a chemical assigned an MEL must be low as is reasonable practicable and, in any case, below the MEL.

• UPPER EXPLOSIVE LIMIT(UEL): The maximum concentration of gas, vapor, mist or dust in air at a given pressure and temperature in which a flame can be propagated.

Chemical hazards

• Risk Control: Exposure to chemicals, resulting in toxic effects or oxygen deficient -atmospheres, may arise in a variety of industrial situations. A summary of common sources, clearly this is not exhaustive since exposure may result whenever materials are mixed, machined, heated dispread (or) otherwise processes (or) used. The precautions naturally vary in each case. For example, to avoid improper admixture of chemical will require. Adequate training, instruction and supervision of workers Identification of chemicals by name and code numbers Segregated storage of incompatible substances.

Chemical hazards

• HAZARD RECOGNITION The toxicity of a substance is its capacity to cause injury once inside the body. The main modes of entry into the body by chemicals in industry are inhalation, ingestion and absorption through the skin. Gases, vapors, mists, dusts, fumes and aerosols can be inhaled and they can also affect the skin, eyes and mucous membranes. Ingestion is rare although possible as a result of poor personal hygiene, subconscious hand-to-mouth contact, or accidents. The skin can be affected directly by contact with the chemicals, even when intact, but its permeability to certain substances also offers a route into the body. Chemicals accorded a ‘skin’ notation in the list of Occupational Exposure Limits may also arise via skin lesions.

Chemical hazards

• Other Chemical Hazards:

• Class 1 Explosive

• Class 2 Gases compressed

• Class 3 Flammable Liquids

• Class 4 Flammable Solids

• Class 5 Oxidizing (5.1 Oxidizing substances, 5.2 Organic per Oxides)

• Class 6 Poisonous (toxic) 6.1 poisonous (toxic), 6.2 Infectious substances.

• Class 7 radioactive

• Class 8 corrosive

Chemical hazards

• Flammable: these are the substances which may get ignited by source of ignition i.e. alcohol, acids etc.

• Explosive: These substances may get explode due source of ignition, temperature increase i.e. ammonium nitrite.

Chemical hazards

• Corrosive: These are the chemicals which corrode the substance while contact i.e. Acids.

• Oxidizing: These are the chemicals which may create depression of oxygen in the atmosphere.

• Reactive: These are the substances which react with other substances i.e. Aluminiumborohydride (Al(BH4)3) if mix with water H2o it will get explode.

Chemical hazards

• Radioactive: These are the substances which may generates radiation in the atmosphere i.e. potassium-40, carbon-14

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