L03 Chemical Hazards PDF

Before we start Non-Ionizing radiation: It includes: ultraviolet (UV), visible light (include laser),...

Before we start Non-Ionizing radiation: It includes: ultraviolet (UV), visible light (include laser), Chemical Hazards infrared, microwave, radio frequency, and extremely low frequency L03 introduction to OHS Generally, it has no health effect beside tissue heating Dr Abdullah Alzhrani (thermal effects) Ultraviolet (UV): the man source is sunlight (prevent exposure to direct sunlight: clothes) Exposure to Ultraviolet can cause skin cancer. It can also harm the eyes (eye protection, e.g. sunglasses) Objectives Introduction Review related chemical and physical properties A chemical hazard is a chemical substance that could potentially Learn common routes of exposure for chemical hazards cause harm to the human body or environment. understand the importance of safety data sheet Chemicals can be: understand the types of chemical hazards Chemical elements chemical molecules chemical compound Mention international chemical classification Identify chemical risk factors and adverse health effect Physical state of matter Chemical hazard Chemicals can be: Not all chemicals considered dangerous. Gas Liquid The majority of occupational health hazards arise from: Solid OR something else inhaling chemical agents in the form of vapors, gases, dusts, Vapor fumes, and mists, or by Mist skin contact with these materials Fumes Smoke dust Route of exposure (Routes of entry) Chemical hazard Inhalation Thousands chemicals used in workplaces and most of these have Skin contact (dermal absorption or dermal contact) toxic effect Ear Eye It is important to identify the used chemicals and determine weather its is dangerous. Injection This include all used raw materials, manufactured products and by-products. Ingestion Not common in workplace in general, the manufacturer of chemical substance issue a Safety Data Sheet (SDS). Safety Data Sheet (SDS) Safety Data Sheet (SDS) Example of SDS The SDS is a summary of the important health, safety, and toxicological information on the chemical or the mixture ingredients. Such as: Name, chemical composition and dates (production and expiry) Toxicity Use, storage and transportation Required control (e.g. PPE) First aid and response to emergency Chemical Hazards – types of chemicals Types of Airborne Contaminants Air contaminants DUSTS: Hazardous chemicals  Dust is airborne solid particles that range in size from 0.1–25 µm in Dangerous goods diameter (1 µm = 0.0001 cm).  Generated by handling, crushing, grinding, rapid impact, detonation, and decrepitation (breaking apart by heating) of organic or inorganic materials, such as rock, ore, metal, coal, wood, and grain. Size in the most important factor:  Dusts more than 5 µm in size usually do not remain airborne long enough to present an inhalation problem  Dust particles must usually be smaller than 5 µm in order to penetrate to the alveoli or inner recess of the lungs.  Types of Airborne Contaminants Dust Dust 14 Types of Airborne Contaminants Chemical Hazards -Types of Airborne Contaminants Fumes Fumes  formed when the material from a volatilized solid condenses in cool air.  Fumes are extremely fine solid particles (usually less than 1.0 µm in Welding diameter. Metalising  In most cases, the hot vapor reacts with the air to form an oxide.  Welding, metalizing  fumes formed when welding structures that have been painted with lead- based paints or when welding galvanized metal, can produce severe symptoms of toxicity  Gases and vapors are not fumes, although the terms are often mistakenly used interchangeably. 16  Types of Airborne Contaminants Types of Airborne Contaminants Smoke Mists  This consists of carbon or soot particles less than 0.1 µm in size, and  These are suspended liquid droplets generated by condensation of results from the incomplete combustion of carbonaceous materials liquids from the vapor back to the liquid state or by breaking up a liquid such as coal or oil. into a dispersed state, such as by splashing, foaming, or atomizing.  Smoke generally contains droplets as well as dry particles. Tobacco, for  The term mist is applied to a finely divided liquid suspended in the instance, produces a wet smoke composed of minute tarry droplets. atmosphere.  Examples are: Smoke  the oil mist produced during cutting and grinding operations,  paint spray mist in painting operations, and  the condensation of water vapor to form a fog or rain. Types of Airborne Contaminants Types of Airborne Contaminants Mists Aerosols  are liquid droplets or solid particles of fine enough particle size to Mist (1:35) remain dispersed in air for a prolonged period of time. Mist 2 Aerosols 19  Types of Airborne Contaminants Types of Airborne Contaminants Vapor Gases  These are the volatile form of substances that are normally in the solid or liquid state at room temperature and pressure.  These are formless fluids that expand to occupy the space or enclosure in which they are confined.  Evaporation is the process by which a liquid is changed into the vapor  Gases are a state of matter in which the molecules are unrestricted by state and mixed with the surrounding atmosphere. cohesive forces.  Evaporation process starts before reaching the boiling point (i.e. at room  Examples are arc-welding gases, internal combustion engine exhaust temperature) gases, CO, CO2, and air.  Compressed Gas cylinders has inherent danger in their handling  Volatile organic compounds (VOC) and solvents with low boiling points  Cryogenic liquids (very cold) could cause frostbite and asphyxiation volatilize readily at room temperature.  e.g. Methanol (64.7°C), Ethanol (78.4 °C), Benzene (80.1 °C)  (for reading) (when gas replace oxygen in the air) Types of Airborne Contaminants Particulates matter  Dusts, fumes, fibers, and mists are all particulates.  Particulate matter (PM) is small (less than 100 micrometers in diameter) pieces of solid materials, liquid droplets, or microbiological organisms.  On the other end of the spectrum, particles smaller than about 0.001 µm start to act like gases, and thus are not treated as particulate matter.  Most often, particulate matter is regarded as a hazard when suspended in air (when the size is less than 100 micrometers), which can then be inhaled. https://www.geeksforgeeks.org/evaporation/  https://www.visualcapitalist.com/wp-content/uploads/2020/10/RelativeSizeofParticles-Infographic-1200px_v8.jpg Types of Airborne Contaminants Chemical Hazards Dangerous Chemicals and dangerous goods Particulates matter Chemicals and other substances that can cause injury or illness.  While exposure to particulate matter as an aerosol is the most common route, some types of PM may be hazardous by ingestion or skin contact. this include any chemical that is: Explosive Flammable  Examples: Oxidizing  Sir Percival Pott identified cancer caused by skin contact with soot among Corrosive (strong acids and bases) chimney sweeps as early as 1775. Toxic (to human, animals or environment)  Lead particles that have settled out of the air onto eating surfaces can be Volatile organic compounds absorbed through the gastrointestinal tract to cause systemic poisoning. Radioactive materials  Hazard pictograms (For reading) Chemical Hazards – Classification The Globally Harmonized System (GHS) was developed by the United Nations for international standardization of hazard classification and communication. Hazard pictograms alert us to the presence of a hazardous chemical https://www.hse.gov.uk/chemical-classification/labelling-packaging/hazard- symbols-hazard-pictograms.htm Hazard pictograms (For reading) Hazard pictograms (For reading) https://www.esafetysupplies.com/products/nm-hmc14a-pt Chemical hazard control Chemical hazards – Risk factors It is important to know the type of chemical hazard (dust, gas, mist, etc… ) to choose the best control measure 1. Chemical prosperities Highly water soluble compounds affect the upper respiratory tract (e.g. ammonia and formaldehyde) Low water soluble compounds affect the lunges (e.g. ozone and phosgene) Non-soluble compounds enters deep in the lung and diffuse in the blood (e.g. benzene, chlorinated solvents) 2. Particle size and structure The smaller the size the grater chance of reaching deep in the lungs Crystalline structures likely to cause more damage (e.g. crystalline silica) For air contaminant, Size is the most Chemical hazards – Risk factors important risk factor 3. The extent and rate at which a substance will be absorbed by the body depends on the properties of the chemical, for example: Solubility in lipids – Lipophilic chemicals (e.g. fats and oils) can concentrate in the body fat or any other lipid tissues such as the brain Solubility in water – very water soluble chemicals can be distributed throughout the body water pH 4. Route of exposure (inhalation, skin contact, injection) are important. Chemical hazard – adverse health effects Chemical hazard – adverse health effects The toxicity of chemical can be one or more of the following The toxicity of chemical can be acute or chronic Irritant chemicals: cause irritation to body tissues Corrosive: dissolve body tissue Some chemicals have specific effect organ or system Sensitizers: cause allergy after repeated exposure Lead: affect development (central nerve system) Asphyxiants: cause oxygen deprivation Mercury: Anesthetic and narcotic: those have anesthetic effect or addiction Chronic effect: “Mad hatter disease” Acute exposure: kidney failure and death Systematic poisons: have s target organs or target system. Carcinogens: cause cancer CO: chemical asphyxiation( cause death in short time) Teratogens: causes an abnormality following fetal exposure during pregnancy Mutagens: cause genetic mutation