Chapter 2 Chemical Safety PDF

CHAPTER 2 Chemical Safety LEARNING OBJECTIVES At the end of this lesson, the student should be able to: 1. understand the fundamentals of chemical safety as well as the safety in the laboratory; 2. identify...

CHAPTER 2 Chemical Safety LEARNING OBJECTIVES At the end of this lesson, the student should be able to: 1. understand the fundamentals of chemical safety as well as the safety in the laboratory; 2. identify and illustrate the Globally Harmonized System (GHS) and pictograms; and 3. appreciate the importance of chemical safety in day-to-day life. INTRODUCTION Nowadays, a wide range of chemicals are being used in the different field, most especially in the field of research, medicine, product manufacturing and even in our daily living. We utilize chemicals since it enables us to formulate substances important for disease treatment, fertilize plants and provide fuel for transportation. According to the International Labour Organization (ILO) that chemicals have become part of our life, sustaining many of our activities, preventing and controlling many diseases and increasing agricultural productivity. However, one cannot ignore that many of these chemicals may, especially if not properly used, endanger our health and poison our environment. Moreover, it has been estimated that approximately one thousand new chemicals come onto the market every year, and about 100,000 chemical substances are used on a global scale. With this topic, that talks about chemical safety we can be able to view the physical and health hazards of chemicals, that requires implementation of safety precautions and hazard control that can reduce the risk of exposure. WHAT IS CHEMICAL SAFETY? It is the application of the best practices for handling chemicals and chemistry processes to minimize risk, whether to a person, facility, or community. It involves understanding the physical, chemical and toxicological hazards of chemicals, (Kemsley, 2013). Chemical safety provides information about the practice of handling chemicals in a safe manner, thus minimizing the hazard to public and personal health. According to the World Health Organization (WHO), chemical safety is achieved by undertaking all activities involving chemicals in such a way as to ensure the safety of human health and the environment. It covers all chemicals, natural and manufactured, and the full range of exposure situations from the natural presence of chemicals in the environment to their extraction or synthesis, industrial production, transport use and disposal. Focus of Chemical Safety 1. Identify the hazard: This involves identifying the chemicals you have in your workplace and the hazards associated with them.  2. Assess the risk: This involves assessing the risk from chemicals or processes in your workplace. 3. Control the exposure: This involves considering the various recognized control measures to eliminate or reduce the risk. CHEMICAL HAZARD A chemical hazard is a type of occupational hazard caused by exposure to chemicals in the workplace. Chemical hazards will give an idea to the user on what are the things that needs to be observe, what are the preventive measures that needs to be done, and what are the things needed and not needed in order to handle chemicals safely. (Indian Standard (IS) 4209-1987 Code of Safety in Chemical Laboratories.) Types of Chemical Hazard 1. Corrosives Corrosives are chemicals which cause burns on the skin, mucous membrane and eyes. Chemical burns are also caused when tissues come in contact with corrosive solids, corrosive liquids dispersed in the air as mists. This kind of chemicals are highly reactive substances it can cause obvious damage to living tissue. Examples of corrosives are: a. Sulfuric acid b. Nitric acid c. Potassium hydroxide (caustic potash) d. Sodium hydroxide (caustic soda) e. Bromine and phenol 2. Oxidizers Oxidizers are solid, liquids or gases that react readily with most organic material or reducing agents with no energy input. Oxidizers are severe fire hazards. They must be stored away from flammables, since they can start a fire if they come in contact with each other. Thus, oxidizing chemicals can cause fire and can burn violently. Examples of oxidizers are: a. Hydrogen Peroxide b. Nitric Acid c. Perchloric Acid d. Sulphuric Acid e. Chlorates f. Chromates 3. Flammable Flammable substance are those gases, liquids and solids that will ignite and continue to burn in air if exposed to a source of ignition. Flammable chemicals are a fire hazard. The lower the flashpoint (the lowest temperature at which a liquid fuel will give off enough vapour to form a momentarily ignitable mixture with air.) of the chemical, the greater the hazard. Examples of flammable chemicals are: a. Acetone b. Toluene  c. Methyl alcohol 4. Water reactive Water reactive chemicals are dangerous when wet because they will undergo a chemical reaction with water. This reaction may release a gas that is either flammable or present a toxic health hazard. Examples of water reactive chemicals are: a. Sodium b. Lithium c. Potassium 5. Pyrophorics Pyrophoric chemicals are substances that ignite instantly upon exposure to oxygen, they can also be water reactive, where heat and hydrogen (a flammable gas) are produced. These are liquids, solids and gases that will ignite spontaneously in air at or below 130 degrees Fahrenheit, handling and usage of pyrophoric require fire resistant lab coat, fire resistant hand gloves, safety glasses and face shield. Examples of these chemicals include: a. Butyl Lithium b. Diisobutylaluminium Hydride 6. Toxic Toxic chemicals are substance that can cause harmful effect to the environment and hazardous to human health if inhaled, ingested or absorbed through the skin. Toxic chemicals produce injurious or lethal effects upon contact with body cells due to their chemical properties. The extent of exposure is determined by the dose, duration and frequency of exposure and the route of exposure. 5 Types of Toxic Chemicals 1. Neurotoxins- the target organ for this type of toxic chemical is the nervous system. Examples: xylene, carbon-hexane, trichloroethylene. 2. Hematotoxins – the target part is the blood. Examples: carbon monoxide, nitrates 3. Hepatotoxins – the target part is the liver. Examples: chloroform, dinitrobenzene 4. Nephrotoxins – the target part is the kidney. Examples: cadmium, mercury, carbon 5. Dermatotoxins – the target part is the skin. Examples: organic solvents 7. Potentially Explosive Chemicals An explosive chemical is a solid or liquid chemical which is in itself capable by chemical reaction of producing gas at such a temperature and pressure and at such a speed to cause damage to the surroundings. This are chemicals that when subjected to heat, impact, or friction, undergoes rapid chemical change, evolving large volumes of gases which cause sudden increase in pressure. Examples of potentially explosive chemicals: a. Acetylides  b. Azides c. Nitrogen triiodide d. Organic nitrates e. Nitro compounds f. Perchlorate salts PICTOGRAMS According to the Canadian Centre for Occupational Health and Safety (CCOHS), the Hazard Communication Standard (HCS) requires pictograms on labels to alert users of the chemical hazards to which they may be exposed, each pictogram consist of a symbol on a white background framed within a red border and represent a distinct hazard. There are two classification of pictograms the Health Hazard Pictogram and Physical Hazard Pictogram. Classification of Pictograms 1. Health Hazard Pictogram 2. Physical Hazard Pictogram 3. Environment CHEMICAL HEALTH RISK A chemical incident is the unexpected release of a substance that is (potentially) hazardous either to humans, other animals or the environment. Chemical releases arise from technological incidents, impact of natural hazards4, and from conflict and terrorism.5 The International Federation of the Red Cross has estimated that between 1998 and 2007, there were nearly 3 200 technological disasters, including chemical incidents, with approximately 100 000 people killed and nearly 2 million people affected.5 The management of chemical incidents requires a multidisciplinary and multi-sectoral approach - the health sector may play a supporting or a leadership role at various stages of the management. (WHO Human Health Risk Assessment Toolkit: Chemical Hazards. 2010). The following are the identified chemical health risk: 1. FIRE produces injuries through heat and exposure to toxic substances (including combustion products). 2. EXPLOSION produces traumatic (mechanical) injuries through the resulting shockwave (blast), fragments and projectiles. 3. TOXICITY may result when humans come into contact with a chemical released from its containment, be it from storage or transport, or as reaction or combustion products. Toxicity can cause harm by a wide array of toxic mechanisms ranging from chemical burns to asphyxiation and neurotoxicity. 4. MENTAL HEALTH effects are not only determined by exposure to the chemical, fire or explosion but also by “exposure to the event” itself. Routes of Entry of Chemicals to our Body 1. Inhalation into lungs. 2. Absorption through skin membrane/cuts in the skin. 3. Ingestion via mouth into the gastrointestinal system. Common Chemical Groups that cause Health Risks or Specific Chemical Hazards The use of chemicals has increased dramatically due to the economic development in various sectors including industry, agriculture and transport. As a consequence, people are exposed to a large number of chemicals of both natural and man-made origin (World Health Organization). Chemicals come from different sources and also come in different forms. Human exposure to hazardous chemicals can occur at the source or the chemical could move to a place where people can come into contact with it. The chemical getting into our body has had an adverse effect on our health. Thus, creates a greater risk in experiencing different kinds of symptoms and diseases. Health effects depend on the toxicity of a chemical group that entered our body, on the rate of absorption of the body and the response of the body to the chemical (Missouri Department of Health & Senior Services). 1. Dust and Fumes All particles may be harmful; the effect depends on size of particles, amount and nature of substance. Particles less than 10 μm can be breathed deep in the lungs and those less than 2.5 μm is particularly dangerous. Dusts containing crystalline silica or asbestos may cause incurable lung damage leading to cancer, especially in smokers: metal fumes may cause “metal fume fever” (Duffus, J. & Worth, H.,n.d.) 2. Gases Gases such as sulfur oxides, nitrogen oxides, chlorine and ammonia are corrosive and irritating to the lungs and nose (Duffus, J. & Worth, H., n.d.)  a. Phosgene is formed when solvents containing chlorine, such as trichloroethane, trichloroethylene, or carbon tetrachloride come into contact with hot surfaces or flames. b. Carbon monoxide is an odorless and colorless gas formed by incomplete burning of carbon compounds: Carbon monoxide gradually blocks oxygen supply to the nervous system, making your brain function less effectively before it causes death; it reacts with hemoglobin stopping it carrying oxygen in the blood. c. Hydrogen cyanide gas can pass through the skin as well as the lungs and kills by depriving your brain and heart of oxygen; it reacts with the final electron carrier of the cytochrome system to block cell respiration. 3. Solvents Apart from water, most solvents are liquid organic chemicals and many evaporate rapidly at room temperature. Organic solvents are often flammable: organic solvent vapors may be inhaled or the liquid absorbed through the skin. a. Benzene can cause leukemia, a cancer of the white blood cells. b. Carbon tetrachloride can cause severe liver damage. c. Carbon disulfide affects the brain and nervous system causing character change and unpredictable behavior. 4. Acids and Bases Acids and bases have corrosive properties. The amount of harm caused by chemical burns from acids and bases depends on the concentration of the substance and the duration of exposure (Retrieved from https://sciencing.com/acids- basesharmful-6019071.html). a. Strong Acids. Acids with a pH of less than 4 can cause chemical burns. Some common strong acids include hydrochloric, nitric, sulfuric and phosphoric acids. Weak acids such as acetic, citric and carbonic are not corrosive. They can safely be consumed and do not irritate the skin. However, at greater concentrations weak acids can be harmful. b. Strong Bases. Bases with a pH greater than 10 can cause chemical burns. Strong bases include, calcium hydroxide, sodium hydroxide and potassium hydroxide. Some common weak bases are ammonia and sodium bicarbonate. Chemical burns from bases do not cause as much pain as acid burns, but the damage can be more extensive. 5. Metals Metals are substances with high electrical conductivity, malleability, and luster, which voluntarily lose their electrons to form cations. Metals are found naturally in the earth's crust and their compositions vary among different localities, resulting in spatial variations of surrounding concentrations (Anbalagan, N. et.al., 2014). Metals are well known for its adverse benefits and uses. But other sources of metal could have a harmful effect on the environment and living organisms. Heavy Metals Heavy metals are generally referred to as those metals which possess a specific density of more than 5 g/cm3 and adversely affect the environment and living organisms. These metals are quintessential to maintain various biochemical and physiological functions in living organisms when in very low concentrations; however they become noxious when they exceed certain threshold concentrations. Heavy metal toxicity has proven to be a major threat and there are several health risks associated with it. The toxic effects of these metals, even though they do not have any biological role, remain present in some or the other form harmful for the human body and its proper functioning. They sometimes act as a pseudo element of the body while at certain times they may even interfere with metabolic processes (Anbalagan, N. et.al., 2014). It is being said that heavy metal exposure continues and is increasing in many parts of the world. Heavy metals are significant environmental pollutants and their toxicity is a problem of increasing significance for ecological, evolutionary, nutritional and environmental reasons. Various sources of heavy metals include soil erosion, natural weathering of the earth's crust, mining, industrial effluents, urban runoff, sewage discharge, insect or disease control agents applied to crops, and many others. Common Heavy Metals a. Lead Lead is a highly toxic metal whose widespread use has caused extensive environmental contamination and health problems in many parts of the world. Lead is an extremely toxic heavy metal that disturbs various plant physiological processes and unlike other metals, such as zinc, copper and manganese, it does not play any biological functions. Lead metal causes toxicity in living cells by following ionic mechanism and that of oxidative stress. Under the influence of lead in the body system, there will be an imbalance between the production of free radicals and antioxidants to detoxify the reactive intermediates or to repair resulting damage in the body (Anbalagan, N. et.al., 2014). The sources of lead were gasoline and house paint, which has been extended to lead bullets, plumbing pipes, pewter pitchers, storage batteries, toys and faucets. b. Mercury Mercury is very toxic and exceedingly bio accumulative. Its presence adversely affects the marine environment and hence many studies are directed towards the distribution of mercury in water environment. It is well known as a hazardous metal and its toxicity is a common cause of acute heavy metal poisoning. The brain remains the target organ for mercury, yet it can impair any organ and lead to malfunctioning of nerves, kidneys and muscles. It can cause disruption to the membrane potential and interrupt with intracellular calcium homeostasis. Mercury plays a key role in damaging the tertiary and quaternary protein structure and alters the cellular function by attaching to the selenohydryl and sulfhydryl groups which undergo reaction with methyl mercury and hamper the cellular structure. It also intervenes with the process of transcription and translation resulting in the disappearance of  ribosomes and eradication of endoplasmic reticulum and the activity of natural killer cells. Mercury exists mainly in three forms: metallic elements, inorganic salts and organic compounds, each of which possesses different toxicity and bioavailability. These forms of mercury are present widely in water resources such as lakes, rivers and oceans where they are taken up by the microorganisms and get transformed into methyl mercury within the microorganism, eventually undergoing biomagnification causing significant disturbance to aquatic lives (Anbalagan, N. et.al., 2014). Major sources of mercury pollution include anthropogenic activities such as agriculture, municipal waste water discharges, mining, incineration, and discharges of industrial waste water. c. Chromium The most commonly occurring forms of Cr are trivalent- Cr+3 and hexavalent- Cr+6, with both states being toxic to animals, humans and plants. In order to determine the activities of the metal ions in the environment, metal speciation is very important where in case of chromium the oxidative form of Cr(III) is not an essential contaminant of the ground water but Cr(VI) has been found to be toxic for humans. Chromium is extensively used in industries such as metallurgy, electroplating, production of paints and pigments, tanning, wood preservation, chemical production and pulp and paper production. These industries play a major role in chromium pollution with an adverse effect on biological and ecological species. A wide range of industrial and agricultural practices increase the toxic level in the environment causing concern about the pollution caused by chromium. Pollution of the environment by chromium, particularly hexavalent chromium, has been the greatest concern in recent years. The discharge of industrial wastes and ground water contamination has drastically increased the concentration of chromium in soil. During manufacturing of chromate, the deposit of the Cr residues and waste water irrigation posed a serious Cr pollution to farmland. With the implementation of modern agriculture there is continuous release of Cr into the environment by means of Cr residues, Cr dust and Cr waste water irrigation, resulting in soil pollution affecting the soil-vegetable system and disturbing the vegetable yield and its quality to humans (Anbalagan, N. et.al., 2014). d. Arsenic Arsenic is one of the heavy metals causing disquiet from both ecological and individual health standpoints. Arsenic is a protoplastic poison since it affects primarily the sulphydryl group of cells causing malfunctioning of cell respiration, cell enzymes and mitosis. Deliberate consumption of arsenic in case of suicidal attempts or accidental consumption by children may also result in cases of acute poisoning (Anbalagan, N. et.al., 2014). Many common arsenic compounds can dissolve in water, thus arsenic can contaminate lakes, rivers, or underground water by dissolving in rain, snow, or through discarded industrial wastes. Therefore, arsenic contamination in ground water is a serious public health threat worldwide. In addition, the effect of chronic arsenic exposure from ingested arsenic-contaminated food and water or inhaled contaminated air has been investigated in various countries and found to be associated with detrimental health effects such as hyperpigmentation, keratosis, various types of cancer and vascular diseases (Chung, J.Y., Hong, Y.S., & Y, S.D., 2014)  Humans may encounter arsenic by natural means, industrial source, or from unintended sources. Drinking water may get contaminated by use of arsenical pesticides, natural mineral deposits or inappropriate disposal of arsenical chemicals. 6. Pesticides According to the Environmental Protection Agency (EPA), a pesticide is any substance or mixture of substances intended for preventing, destroying, repelling or mitigating any pest. The term pesticide also applies to herbicides, fungicides, and various other substances used to control pests. Pesticides also include plant regulators, defoliants and desiccants. Pesticide is actually a pesticide formulation that contains a number of different materials, including active and inert ingredients, as well as contaminants and impurities. In addition, pesticides, when subject to various environmental conditions, break down to other materials known as metabolites, which are sometimes more toxic than the parent material (Beyond Pesticides. ND). Based on FAO (1989) a pesticide is any substance or mixture of substances intended for preventing, destroying, or controlling any pest including vectors of human or animal diseases, unwanted species of plants or animals causing harm during, or otherwise interfering with, the production, processing, storage, or marketing of food, agricultural commodities, wood and wood products, or animal feed stuffs, or which may be administered to animals for the control of insects, arachnids or other pests in or on their bodies. The term, however excludes such chemicals used as fertilizers, plant and animal nutrients, food additives and animal drugs. The term pesticide is also defined by FAO in collaboration with UNEP (1990) as chemicals designed to combat the attacks of various pests and vectors on agricultural crops, domestic animals and human beings. The definitions above imply that, pesticides are toxic chemical agents (mainly organic compounds) that are deliberately released into the environment to combat crop pests and disease vectors (Zacharia, J.T., 2011). Other functions of chemicals in pesticides: a. Plant Regulators Plant growth regulators (also called plant hormones) are numerous chemical substances that profoundly influence the growth and differentiation of plant cells, tissues and organs. Plant growth regulators function as chemical messengers for intercellular communication. There are currently five recognized groups of plant hormones: auxins, gibberellins, cytokinins, abscisic acid (ABA) and ethylene. They work together coordinating the growth and development of cells. Ethylene is mainly involved in abscission and flower secscence in plants and is rarely used in plant tissue culture. b. Defoliants Plant defoliation does not hasten maturity; for maximum yield and crop quality potential, defoliants should not be applied until physiological maturity. Defoliants function in several primary ways, both resulting in more rapid development of abscission layers. The abscission layer is the zone where leaf petioles meet stems. Once adequately formed, leaves drop from the abscission layer. The older materials work by contact—rapid destruction of green tissue, which indirectly favors formation of abscission layers. Several other defoliants do not target green tissue destruction, but promote the formation of the abscission layer directly, resulting in leaf drop. The activity of a defoliant is favored by warm temperatures, particularly greater than 50°F (Fishel, F.M., 2005). c. Desiccants Desiccants are used for purposes similar to the uses of defoliants, but desiccants function differently. Desiccants cause green foliage to lose water—a hastened drying process that results in leaf removal (generally faster than the result of a defoliant). Desiccants have several practical uses in production. They effectively destroy the crop following harvest, quickly eliminating pest harborage sites. In addition to being a useful pest-management tool, desiccants can protect crop quality in other ways. For example, in potato production, the presence of massive green vine material can interfere with the harvest operation. Such interference can result in skinning and bruising of the tubers. Skinned and bruised tubers will readily discolor and are more easily predisposed to soft rot. Lower-quality tubers lower fresh market value, and in some cases such tubers may be rejected entirely (Fishel F.M., 2005). Pesticides are divided into three (3) broad groups based on their chemical composition: a. Organophosphorous Pesticides Over 100 organophosphorus compounds representing a variety of chemical, physical, and biological properties are presently in commercial use. Most are only slightly soluble in water and have a high oil-water partition coefficient and a low vapour pressure. Most, with the exception of dichlorvos, are of comparatively low volatility, and are all degraded by hydrolysis, yielding water-soluble products. Organophosphates (OP) are esters of phosphoric acid. The OP group of pesticides asserts its effects through irreversible inactivation of the enzyme acteylcholinesterase, which is essential for nerve function in humans, insects and many other animals. OP samples degrade rapidly by hydrolysis on exposure to light, air and soil, however small amounts are detected in food and drinking water (Jayaraj, R. et. Al., 2017). These are often acutely poisonous to insects and to humans. They can damage the nervous system and even cause death. They are effective even at low concentrations (International Labour Organization). b. Organochlorine Pesticides Organochlorines pesticides are organic compounds with five or more chlorine atoms. Organochlorines were the first synthetic organic pesticides to be used in agriculture and in public health. Most of them were widely used as insecticides for the control of a wide range of insects, and they have a long-term residual effect in the environment since they are resistant to most chemical and microbial degradations. Organochlorine pesticides act as nervous system disruptors leading to convulsions and paralysis of the insect and its eventual death. Some of the commonly used representative examples of organochlorine pesticides are DDT, lindane, endosulfan, aldrin, dieldrin and chlordane It also acts as endocrine disrupting chemicals (EDCs) by interfering with molecular circuitry and function of the endocrine system. Farm workers, their families and those who pass through a region applied with pesticides can absorb a measurable quantity of pesticides. The presence of pesticide residues has been detected in blood  plasma of workers in agricultural farms. Direct or indirect exposure to pesticides leads to neuromuscular disorders and stimulation of drug and steroid metabolism (Jayaraj, R. et. Al., 2017). c. Carbamates Carbamate pesticides are derived from carbamic acid and kill insects in a similar fashion as organophosphate insecticides. They are widely used in homes, gardens, and agriculture. Like the organophosphates, their mode of action is inhibition of cholinesterase enzymes, affecting nerve impulse transmission (Fishel, F.M., 2005). Toxic exposures to carbamates can occur via dermal, inhalational, and gastrointestinal (GI) exposures. Symptom severity depends on the classification of the pesticide as well as the exposure dose. Carbamate poisoning cases are most often related to intentional oral ingestion or dermal occupational exposure. In the developing world, cases of large outbreaks from contaminated food and crops have been reported (Silberman, J. & Taylor, A. 2018). Unlike organophosphate poisoning, carbamate poisonings tend to be of shorter duration because the inhibition of nervous tissue acetylcholinesterase is reversible, and carbamates are more rapidly metabolized. Muscle weakness, dizziness, sweating, and slight body discomfort are commonly reported early symptoms. Headache, salivation, nausea, vomiting, abdominal pain, and diarrhea are often prominent at higher levels of exposure. Contraction of the pupils with blurred vision, incoordination, muscle twitching, and slurred speech have also been reported (Fishel, F.M., 2005). The World Health Organization (WHO) has classified them into groups according to the danger they might pose to people and the environment: Extremely Hazardous: Aldicarb, Clormephos, Parathion Highly Hazardous: Aldrin, Antu, Warfarin Moderately Hazardous: Cyanophenphos, Cypermethrin, Sulfallate Slightly Hazardous: Allethrin, Kelthane, Malathion MINIMIZING THE RISKS CAUSED BY CHEMICALS IN THE ENTERPRISE Since ancient history, civilizations already used technology which led to further expansion of mankind’s knowledge to the specific branch of science called Chemistry. Chemistry, as defined by Merriam-Webster Dictionary (2018), is the science that deals with the composition, structure, and properties of substances and with the transformations that they undergo. Hence, with its continuous study and implementation, its importance is noted for benefits it give including many valuable social and economic benefits, including better living conditions, improved public health, and enhanced quality of life (American Chemical Society, 2018). The emerging chemistry enterprise since the industrialization era until the present technological era created high-skill and high-wage jobs. Yet, with the concerns about the risks of this industry, people then realized that with the possession of this great power also brought with them great danger. Missouri Department of Health & Senior Services (2018) stressed that human exposure to hazardous chemicals can occur at the source or the chemical could move to a place where people can come into contact with it. Hence, the impending danger leads government leaders, scientists and concern citizens alike to establish standard practices of chemistry from concept through research, development, manufacture, use, and disposal to ensure that it must be done safely and so as to minimize adverse impacts on human health and/or the environment. It is therefore notable that the safety and health of both individuals and the environment is essential for those working with chemicals. Chemists understand that working with chemicals and developing new materials and chemical processes involve some degree of risk. A thoughtful and educated approach to chemical safety must assess the overall life-cycle and risk/benefit analysis for each area of the chemistry enterprise (American Chemical Society, 2018). Minimizing the risks in the enterprise and improving the safe use of chemicals can be achieved at different levels. This process of minimizing risk while optimizing benefits should continue throughout the investigation, development, implementation, use, and appropriate recycling or ultimate disposal of products and by-products. MINIMIZING THE RISKS OF HAZARDS Minimizing the risks of hazards requires an evaluation of an entire experiment and a review of the chemicals used and produced, as well as the equipment, procedures, and PPE. American Chemical Society (2018) pointed out the step-by-step procedure that enables students to discover and collect information for a particular situation while reviewing an experiment. BEFORE AN EXPERIMENT Pre-experiment analysis may be the most important step to take to minimize the risks in any laboratory setting. Incidents can happen even in the best-prepared scenario; however, careful attention to detail can minimize the risks. 1. Carefully develop a list of all of the chemicals used and the quantities needed in an experiment. 2. Use appropriate containers for chemical distribution in the laboratory. 3. Consider the physical arrangement and the facilities available in your laboratory. 4. It is possible that one or more of your students have been identified as requiring accommodation because of special needs, either physical or developmental. In planning the experiment, take particular note of these requests for reasonable accommodation and the best and safest way to address any special needs of your students. DURING AN EXPERIMENT Students should be closely and carefully supervised in the laboratory at all times. The teacher must be physically present during the entire experiment, concentrating on the students the entire time. Even a momentary lack of attention or absence could result in the escalation of an incident or emergency situation. Teachers need to have their full attention on all aspects of the laboratory work at all times.  1. During the pre-laboratory instruction, be sure to point out: potential hazards of the chemicals used; safety considerations in the use of chemicals; proper use of PPE; steps in the procedure that are new to the students or that require particular attention; methods of disposal of excess reagent or the products of a reaction; and emergency procedures specific to the experiment and materials. 2. Students and teachers must wear the appropriate personal protective equipment (PPE) and clothing. 3. Be aware of student handling of chemicals, use of equipment, and good housekeeping procedures: make sure that all apparatus is properly set up before students are allowed to proceed with an experiment; no mixing of chemicals should be allowed, other than that specified in an experimental procedure; chemical products should be turned in or disposed of properly. AFTER AN EXPERIMENT The work is, of course, not completed when the students have finished the experimental procedure. 1. Before the students leave the laboratory, they should return any chemicals (excess reagent, product, or waste) to the appropriate location, or dispose of them as instructed; clean any used glassware and return the items to the appropriate location; and wipe down the work surfaces 2. The teacher should also ensure the following: returned glassware and equipment are clean and in usable, undamaged condition; reagent containers are clean, closed, and properly stored; chemicals requiring disposal are correctly handled; unforeseen events are completely documented to prevent repetition; work surfaces are left clean and dry; and all gas outlets are closed, especially (but not only) if burners were used during the experiment. ORGANIZATIONAL MEASURES Occupational risks assessment and taking action to protect workers’ safety and health is an obligation of each employer. Hence, there are numerous measures considered as relevant for accident prevention, e.g. design and use of more safe equipment and technologies or replacing dangerous equipment and products by non-dangerous or less dangerous ones, improvement of working environment, use and maintenance of personal protective equipment, management and staff training, improvement of communication, etc. (Oshwiki.eu, 2018). 1. Assess chemical hazards and set priorities concerning the safety in the organization; 2. Create emergency plans for the assessed hazards; 3. Organize occupational health care and regular surveys as necessary; 4. Organize contacts with authorities/laboratories to create a monitoring system for chemical hazards, and to reliably measure and/or estimate occupational exposures to chemicals when needed; 5. Start collecting case studies of accidents and sickness records in the enterprise to create a basis for priority measures in the control of hazards;  6. Identify chemicals in use; 7. Obtain information of their hazards; 8. Collect this data and make an inventory list of all chemicals used in the factory: create a Register for Workplace Chemicals; and 9. Involve workers in safety organizations, such as the system of Safety Representatives, and Safety Committees. TECHNICAL MEASURES Technical measures can be used to prevent chemical hazards at source, and to prevent the transfer of dangerous chemicals. By technical means it is possible to reduce the exposure of the worker. Chemical Engineering IIT Bombay (2018) pointed some of the technical measures suitable for chemical enterprises. SUBSTITUTION An effective control method for any hazardous chemical is substitution: a hazardous chemical is replaced with a less hazardous one. This is especially important when the chemicals in question can cause cancer, damage to the reproductive functions or create allergic reactions. Choosing a safer process or changing an old and hazardous process to a less dangerous one effectively reduces the risks. An example of safer choice is to have pellets or paste instead of powdered substances which readily produce high levels of dangerous dusts. Water-based paints and adhesives are available to replace harmful products containing solvents. All possible information should be made available when considering the change of a substance or the whole process so that the new choice does not create unexpected new dangers. Thus, in aiming to elaborate the significance of substituting chemicals, a group of scientists in International Chemical Secretariat or ChemSec developed a list called the SIN List. The SIN List is short for “Substitute It Now!” and consists of chemicals that ChemSec has identified as fulfilling the criteria for “Substances of Very High Concern” as defined by the European Union chemicals regulation REACH. The list is based on credible, publicly available information from existing databases and scientific studies, as well as new research. The aim of the SIN List is to spark innovation towards products without hazardous chemicals by speeding up legislative processes and giving guidance to companies and other actors on which chemicals to start substituting. The SIN List is a known and used tool for chemicals management globally (Chemse.org, 2018). ENGINEERING CONTROL The University of Alberta (2018) emphasized that engineering control are built into equipment or processes to minimize hazards. Engineering controls may be implemented at the source of the hazard, along its path, or at the worker. In addition, American Chemical Society (2018) added that if hazardous chemicals cannot be replaced by less dangerous ones, exposure must be prevented by protecting the worker. This method is often called the closed system. Enclosing the hazardous process or chemical is also an effective method.  One example is to use sealed pipes to transfer solvents and other liquids instead of pouring them in the open air. Vapours and gases caused by spray painting or produced in pickling or hardening baths in the metal industry should be controlled, ventilated and not allowed to enter the workplace air. LOCAL EXHAUST VENTILATION Work Safe New Zealand (2018) stressed that many work processes create harmful dusts, vapours and fumes that contaminate the air. Breathing substances hazardous to health and can cause lung diseases such as occupational asthma, bronchitis and silicosis. It may also result in harm to other organs, such as the liver, kidneys and brain. LEV is an engineering system that captures dusts, vapours, and fumes at their source and transports them away from the worker’s breathing zone. This prevents workers from inhaling these substances and reduces contamination of the general workplace air. It is undeniable that it is not always possible to enclose all dangerous operations. Properly designed local exhaust ventilation is the second choice in order to remove the contaminants at the source. A local exhaust ventilation system consists of a hood, ducts or pipes, a system to collect and separate the pollutants from the clean air, and an efficient fan to create enough suction force. The hazardous gases, fumes and dust can be collected from the vented air. They should not go untreated, straight out, to pollute the surroundings of the factory and the environment. Attention should be paid to the clean air inflow which replaces the exhaust. Inspection, proper maintenance, regular cleaning and changing of filters are essential to protect the worker against hazardous contaminants. GENERAL VENTILATION The University of Vermount (2018) stressed that laboratory ventilation involves the use of supply and exhaust ventilation to control lab emissions, potential exposures, and chemical and biological hazards. A general lab ventilation system is designed to dilute and remove contaminants through general exhaust; provide makeup or replacement air, provide heating, cooling, and humidification; and provide local exhaust for specific lab activities. However, general ventilation does not eliminate a potential exposure and the local exhaust is still the preferred method. Still, where it is difficult or impossible to prevent hazardous chemicals, fumes, dusts, mists or particles from entering the workplace air at the source, general dilution ventilation can be installed. This should be designed to meet the needs of the specific work process and workplace. At its best it should consist of an inflow of clean air and an outflow of exhaust forced by fans at right places. It can also be used with other preventive measures. HOUSEKEEPING When working with dangerous chemicals, a proper housekeeping is essential. It is understandable that it must be achieves. Storage areas must be well organized and kept in order. The transport of chemicals within the industrial premises should be planned and the transport routes kept clear. Maintenance of premises and equipment should also be planned. These tasks should be dedicated to persons/work groups/departments. Workers using the equipment should know the person responsible for repairing faulty equipment. Perhaps, the most famous role model of this notion is the Japanese’s 5s words: Seiri (Sort), Seiton (Straighten, Set), Seiso (Shine, Sweep), Seiketsu (Standardize), Shitsuke (Sustain) which describes the steps of a workplace organization process (Leansixsigmadefinition.com, 2018). In simple terms, the five S methodology helps a workplace remove items that are no longer needed (sort), organize the items to optimize efficiency and flow (straighten), clean the area in order to more easily identify problems (shine), implement color coding and labels to stay consistent with other areas (standardize) and develop behaviors that keep the workplace organized over the long term (sustain). Monitoring the efficiency of housekeeping and inspections should be carried out regularly; this should involve the workers themselves, who are experts in their own work. PERSONAL PROTECTIVE EQUIPMENT According to Silva (2017) states that Personal Protective Equipment (PPE) it refers to protective clothing, helmets, goggles, or other garments or equipment designed to protect the wearer’s body from injury or infection. These hazards addressed by protective equipment include physical, electrical, heat, chemicals, biohazards, and airborne particulate matter. Also, this protective equipment may be worn for job-related occupational safety and health purposes, as well as for sports and other recreational activities. 1. EYE AND FACE PROTECTION Occupational Safety and Health Administration (2004) states that employees can be exposed to a large number of hazards that pose danger to their eyes and face. They require employers to ensure that employees have appropriate eye or face protection if they are exposed to eye or face hazards from flying particles, molten metal, liquid chemicals, acids or caustic liquids, chemical gases or vapors, potentially infected material or potentially harmful light radiation. The most common types of eye and face protection include the following: a. Safety spectacles. These protective eyeglasses have safety frames constructed of metal or plastic and impact-resistant lenses. Side shields are available on some models (OSHA, 2004). b. Goggles. These are tight-fitting eye protection that completely cover the eyes, eye sockets and the facial area immediately surrounding the eyes and provide protection from impact, dust and splashes. Some goggles will fit over corrective lenses (OSHA, 2004). c. Welding shields. It is constructed of vulcanized fiber or fiberglass and fitted with a filtered lens, welding shields protect eyes from burns caused by infrared or intense radiant light; they also protect both the eyes and face from flying sparks, metal spatter and slag chips produced during welding, brazing, soldering and cutting operations. OSHA requires filter lenses to have a shade number appropriate to protect against the specific hazards of the work being performed in order to protect against harmful light radiation (OSHA, 2004).  d. Laser safety goggles. These specialty goggles protect against intense concentrations of light produced by lasers. The type of laser safety goggles an employer chooses will depend upon the equipment and operating conditions in the workplace (OSHA, 2004). e. Face shields. These transparent sheets of plastic extend from the eyebrows to below the chin and across the entire width of the employee’s head. Face shields protect against nuisance dusts and potential splashes or sprays of hazardous liquids but will not provide adequate protection against impact hazards. Face shields used in combination with goggles or safety spectacles will provide additional protection against impact hazards. Each type of protective eyewear is designed to protect against specific hazards (OSHA, 2004). 2. HEAD PROTECTION Furthermore, protecting employees from potential head injuries is a key element of any safety program. A head injury can impair an employee for life, or it can be fatal. Wearing a safety helmet or hard hat is one of the easiest ways to protect an employee’s head from injury. Hard hats can protect employees from impact and penetration hazards as well as from electrical shock and burn hazards (OSHA, 2004). However, there are many types of hard hats available in the marketplace today. In addition to selecting protective headgear that meets ANSI standard requirements, employers should ensure that employees wear hard hats that provide appropriate protection against potential workplace hazards. It is important for employers to understand all potential hazards when making this selection, including electrical hazards. This can be done through a comprehensive hazard analysis and an awareness of the different types of protective headgear available. Hard hats are divided into three industrial classes: a. Class A Hard Hats. It provides impact and penetration resistance along with limited voltage protection up to 2,200 volts (OSHA, 2004). b. Class B Hard Hats. It provides the highest level of protection against electrical hazards, with high-voltage shock and burn protection (up to 20,000 volts). They also provide protection from impact and penetration hazards by flying/falling objects (OSHA, 2004). c. Class C Hard Hats. It provides lightweight comfort and impact protection but offer no protection from electrical hazards (OSHA, 2004). 3. FOOT AND LEG PROTECTION OSHA (2004) states that employees who face possible foot or leg injuries from falling or rolling objects or from crushing or penetrating materials should wear protective footwear. Also, employees whose work involves exposure to hot substances or corrosive or poisonous materials must have protective gear to cover exposed body parts, including legs and feet. Foot and leg protection choices include the following: a. Leggings. It protects the lower legs and feet from heat hazards such as molten metal or welding sparks. Safety snaps allow leggings to be removed quickly (OSHA, 2004).  b. Metatarsal Guards. It protects the instep area from impact and compression. Made of aluminum, steel, fiber or plastic, these guards may be strapped to the outside of shoes (OSHA, 2004). c. Toe Guards. It fit over the toes of regular shoes to protect the toes from impact and compression hazards. They may be made of steel, aluminum or plastic (OSHA, 2004). d. Combination Foot and Shin Guards. It protects the lower legs and feet and may be used in combination with toe guards when greater protection is needed (OSHA, 2004). e. Safety Shoes. Have impact-resistant toes and heat-resistant soles that protect the feet against hot work surfaces common in roofing, paving and hot metal industries. The metal insoles of some safety shoes protect against puncture wounds. Safety shoes may also be designed to be electrically conductive to prevent the buildup of static electricity in areas with the potential for explosive atmospheres or nonconductive to protect employees from workplace electrical hazards (OSHA, 2004). 4. HAND AND ARM PROTECTION In addition, OSHA (2004) states that there are many types of gloves available today to protect against a wide variety of hazards. The nature of the hazard and the operation involved will affect the selection of gloves. The variety of potential occupational hand injuries makes selecting the right pair of gloves challenging. It is essential that employees use gloves specifically designed for the hazards and tasks found in their workplace because gloves designed for one function may not protect against a different function even though they may appear to be an appropriate protective device. Gloves made from a wide variety of materials are designed for many types of workplace hazards. In general, gloves fall into three groups: a. Leather, Canvas or Metal Mesh Gloves Leather Gloves. It protects against sparks, moderate heat, blows, chips and rough objects (OSHA, 2004). Aluminized Gloves. It provides reflective and insulating protection against heat and require an insert made of synthetic materials to protect against heat and cold (OSHA, 2004). Aramid Fiber Gloves. It protects against heat and cold, are cut- and abrasive resistant and wear well (OSHA, 2004). Synthetic Gloves. It offers protection against heat and cold, are cut- and abrasive-resistant and may withstand some diluted acids. These materials do not stand up against alkalis and solvents (OSHA, 2004). b. Fabric and Coated Fabric Gloves Fabric Gloves. It protects against dirt, slivers, chafing and abrasions. They do not provide sufficient protection for use with rough, sharp or heavy materials. Adding a plastic coating will strengthen some fabric gloves (OSHA, 2004). Coated Fabric Gloves. It is normally made from cotton flannel with napping on one side. By coating the unsnapped side with plastic, fabric gloves are transformed into general-purpose hand protection offering slip-resistant  qualities. These gloves are used for tasks ranging from handling bricks and wire to chemical laboratory containers. When selecting gloves to protect against chemical exposure hazards, always check with the manufacturer or review the manufacturer’s product literature to determine the gloves’ effectiveness against specific workplace chemicals and conditions (OSHA, 2004). c. Chemical- and Liquid-Resistant Gloves Butyl Gloves. It is made of a synthetic rubber and protect against a wide variety of chemicals, such as peroxide, rocket fuels, highly corrosive acids (nitric acid, sulfuric acid, hydrofluoric acid and red-fuming nitric acid), strong bases, alcohols, aldehydes, ketones, esters and nitro compounds. Butyl gloves also resist oxidation, ozone corrosion and abrasion, and remain flexible at low temperatures. Butyl rubber does not perform well with aliphatic and aromatic hydrocarbons and halogenated solvents (OSHA, 2004). Natural (latex) Rubber Gloves. It is comfortable to wear, which makes them a popular general-purpose glove. They feature outstanding tensile strength, elasticity and temperature resistance. In addition to resisting abrasions caused by grinding and polishing, these gloves protect employees’ hands from most water solutions of acids, alkalis, salts and ketones (OSHA, 2004). Neoprene Gloves. It is made of synthetic rubber and offer good pliability, finger dexterity, and high density and tear resistance. They protect against hydraulic fluids, gasoline, alcohols, organic acids and alkalis. They generally have chemical and wear resistance properties superior to those made of natural rubber (OSHA, 2004). Nitrile Gloves. These are made of a copolymer and provide protection from chlorinated solvents such as trichloroethylene and perchloroethylene. Although intended for jobs requiring dexterity and sensitivity, nitrile gloves stand up to heavy use even after prolonged exposure to substances that cause other gloves to deteriorate. They offer protection when working with oils, greases, acids, caustics and alcohols but are generally not recommended for use with strong oxidizing agents, aromatic solvents, ketones and acetates (OSHA, 2004). 5. BODY PROTECTION However, employees who face possible bodily injury of any kind that cannot be eliminated through engineering, work practice or administrative controls, must wear appropriate body protection while performing their jobs. In addition to cuts and radiation, the following are examples of workplace hazards that could cause bodily injury; temperature extremes, hot splashes from molten metals and other hot liquids, potential impacts from tools, machinery and materials, hazardous chemicals. In addition, there are many varieties of protective clothing available for specific hazards. Students/employers are required to assure that their employees wear personal protective equipment only for the parts of the body exposed to possible injury. Examples of body protection include laboratory coats,  coveralls, vests, jackets, aprons, surgical gowns and full body suits. Protective clothing comes in a variety of materials, each effective against particular hazards, such as: a. Paper-like Fiber. It is used for disposable suits provide protection against dust and splashes (OSHA, 2004). b. Treated wool and Cotton. It adapts well to changing temperatures, is comfortable, and fire-resistant and protects against dust, abrasions and rough and irritating surfaces (OSHA, 2004). c. Duck. It is a closely woven cotton fabric that protects against cuts and bruises when handling heavy, sharp or rough materials (OSHA, 2004). d. Leather. It is often used to protect against dry heat and flames (OSHA, 2004). e. Rubber, Rubberized Fabrics, Neoprene and Plastics. It protect against certain chemicals and physical hazards. When chemical or physical hazards are present, check with the clothing manufacturer to ensure that the material selected will provide protection against the specific hazard (OSHA, 2004). 6. HEARING PROTECTION OSHA (2004) presents some types of hearing protection include: a. Single-Use Earplugs. It is made of waxed cotton, foam, silicone rubber or fiberglass wool. They are self-forming and, when properly inserted, they work as well as most molded earplugs. b. Pre-formed or Molded Earplugs. It must be individually fitted by a professional and can be disposable or reusable. Reusable plugs should be cleaned after using it. c. Earmuffs. It requires a perfect seal around the ear. The glasses, facial hair, long hair or facial movements such as chewing may decrease the protective value of earmuffs. MINIMIZING THE RISKS CAUSED BY CHEMICALS IN THE LABORATORY A research center or laboratory can be a risky place; working with synthetic concoctions, bunsen burners, glass and other possibly unsafe hardware raises numerous wellbeing and security concerns not to be trifled with (Edulab, 2017). The availability and use of numerous types of safety equipment is fundamental to the exercise of safe science. Safety equipment must be present in well-marked, extraordinary visible, and easily reachable places in or near all laboratories that use hazardous chemicals (Indiana University, 2018). In any case, there are precautionary measures we can take by utilizing safety equipment, and in this document, we expect to list the basics that each research facility/ laboratory should be sheltered. LABORATORY SAFETY EQUIPMENT The following are the safety equipment that each laboratory should contain: 1. Chemical Fume Hoods Chemical fume hoods are one of the most essential things utilized for the assurance of specialists in the laboratory. A chemical fume hood is a compound and  fireproof walled in area with a portable window (band) at the front to permit the client access to the inside. Chemical fume hoods catch, contain, and remove substance emanations. Moreover, chemical fume hoods (with the band down) give a defensive obstruction between laboratory personnel and synthetic concoctions or substance form compounds (Indiana University, 2018). 2. Eye Wash Station and Safety/Emergency shower Eye wash stations and safety showers are utilized to manage substance spills. On the off chance that synthetic compounds interact with the skin or e yes, the influenced body parts ought to be washed altogether with a lot of clean water, and your educator ought to be told. Any defiled pieces of attire are ought to be removed (Texas Education Agency, 2018). 3. Fire extinguisher and Fire Blankets Laboratory personnel have to recognize the places of all fire extinguishers in the laboratory, the type of fires for which they are appropriate, and be trained on how to operate them correctly (Indiana University, 2018). There are different types of fire extinguishers according to Texas Education Agency (2018) which are utilized to smother various types of flames. Utilizing the wrong kind of fire extinguisher might worsen things. TYPES OF FIRE EXTINGUISHER: a. Class A - ordinary combustible materials (paper, wood, cardboard, most plastics) b. Class B - flammable or combustible liquids (gasoline, kerosene, grease, and oil) c. Class C – electrical equipment (appliances, wirings, circuit breakers, outlets) d. Class D - combustible materials often found in chemical laboratories (magnesium, titanium, potassium, sodium) The second type of flame security hardware is the fire blanket. Fire blankets are utilized to cover fires on individuals. To utilize a fire blanket, first expel the blanket from its divider holder. Next, wrap the blanket over the flares on the individual. The fire blanket will obstruct the stream of air to the fire which causes the flame to die (Texas Education Agency, 2018). 4. Flammable Liquid Storage Cabinets “Flammable storage cabinets” are type of safety cabinets which are built and designed for the storage of flammable liquids. To prevent flammable liquids from instantly igniting in the event of a workplace fire, flammable liquids must be stored in flammable storage cabinets (Ingles, 2018). 5. Safety cans A safety can is an approved, closed container, of not more than 5 gallons capacity, having a flash arresting screen, spring closing lid and spout cover and so designed that it will safely relieve internal pressure when subjected to fire exposure (Simplified safety, 2018). The essentials behind a safety can or gas can is to control combustible vapors while giving an advantageous methods for conveying,  apportioning, and putting away to five gallons of combustible fluid or fuel (CP Lab Safety, 2018). 6. Explosion-proof and laboratory-safe refrigeration equipment For our laboratory refrigerators, we have refrigerators for storing flammable, hazardous and volatile materials within explosion proof environments. Flammable material storage refrigerators are designed to reduce the risk of explosion within the cabinet while storing flammable and volatile materials whereas explosion proof refrigerators are designed to reduce the risk of explosion inside and outside of the cabinet while storing hazardous and volatile materials within an explosive environment (Labrepco, 2018). 7. First Aid Kits Apparently, according to Edulab (2018), a basic bit of security gear for any condition; a great medical aid pack ought to contain everything expected to treat nonserious accidents: Bandages; Plasters of varying shapes and sizes; Sterile eye pads; Wound dressing; Disposable gloves; Safety pins; and Antiseptic Wipes As the lab is such a perilous place, we suggest checking the date and load of everything in your first aid packs week by week, renewing any utilized things or any past its utilization date. The guidelines on laboratory safety and chemical use are formulated on the basis of past happenings in the laboratory and the laboratory workers are expected to adhere to safety guidelines and maintain safety standard. THREE CATEGORIES OF LABORATORY HAZARDS 1. Equipment A wide variety of equipment is used for different activities. Most of the equipment is delicate, sensitive and expensive. 2. Gases A variety of compressed gases are used, some of which may be corrosive, flammable, or explosive. 3. Chemicals Acids, bases, etching solutions and solvents are commonly used in materials chemistry and device fabrication. Also called as “hands on” hazards which are hard to control. In order to minimize the risks there are safety precautions that must be implemented. GENERAL SAFETY MEASURE 1. Familiarize yourself with all aspects of safety before using any equipment. 2. Be alert to unsafe conditions of the equipment, procedure and actions, call attention to them so that corrections can be made as soon as possible. 3. Label all storage areas, appropriately and keep all chemicals in properly labeled containers. 4. Date all chemical bottles when received and when opened. 5. Note expiry dates on chemicals. 6. Note storage conditions and adhere to them. 7. Familiarize with the appropriate protective measures when exposed to the following kinds of hazardous materials. Flammable Corrosive Toxic Carcinogen Compressed gases Poisons 8. Post warning signs for unusual hazards such as flammable materials no naked flames or other special problems. 9. Pour more concentrated solutions into less concentrated solutions to avoid violent reactions (add acid to water, not water to acid). 10. Avoid distracting other worker. 11. Use equipment for its designated purpose. PERSONAL SAFETY 1. Always use extracted wet benches for chemical work. 2. Always wear safety glasses at all times in the laboratory. 3. Always wear laboratory coat in the laboratory. 4. Appropriate shoes should be worn in the laboratory. 5. Wear breathing mask as when appropriate. 6. Only trained personnel may use the breathing apparatus. 7. Always use extracted wet benches for chemical work. 8. Always wear safety glasses at all times in the laboratory. 9. Always wear laboratory coat in the laboratory. 10. Appropriate shoes should be worn in the laboratory. 11. Wear breathing mask as when appropriate. 12. Only trained personnel may use the breathing apparatus. PERSONAL HYGIENE 1. Wash hands before leaving the laboratory. 2. Never mouth suck anything in a pipette in the laboratory. 3. No food or drink is allowed in laboratories areas where chemicals are used or stored. 4. Never eat or drink from the laboratory glassware. 5. Keep skin covered in the laboratory. FIRE PREVENTION 1. Aware yourself of ignition sources in the laboratory and service areas. 2. Purchase chemicals in quantities that will be used in not distant future. 3. Always store flammable liquids in appropriate cabinets. 4. Do not store incompatible reagents together. 5. Make sure that all electrical cords and all electrical outlet are in good conditions. 6. Remain out of the area of a fire or incident if you are not in position to help. 7. Familiarize with the setting and condition of fire extinguishers. Broken seals mean its already used. 8. Do not use fire extinguishers unless you are trained and feel confident to do so. HOUSEKEEPING 1. Eliminate safety hazards by maintaining the laboratory work areas in a good state of order. 2. Maintain clear passages to the laboratory exit. 3. Wipe down bench tops and other laboratory surfaces after each use. 4. All equipment should be inspected before use. 5. Keep the laboratory floor dry at all times. Attend to spills immediately and notify other lab workers of slipping hazards. 6. Only authorized personnel should do maintenance work on laboratory equipment. EMERGENCY PROCEDURES 1. Please familiarize with the location, use and limitations of the following safety device: Eye wash station Breathing apparatus Spill cleanup materials First aid kit Fire alarm Fire extinguisher 2. If volatile, flammable, or toxic material spill, shut off flames and spark-producing equipment at once. 3. In the event of explosion, call for help CHEMICAL STORAGE AND CHEMICAL WASTE We had recently tackled many topics about chemistry dealing with different distinct branches that emphasize subsets of chemical concepts, determining variety of chemical compositions of substances, and the chemicals around us that we lived with. We need to emphasize the essence of storing chemicals and how its wastes are disposed. Nearly all industries, including the agri-food industry and the service industry, use chemicals in variable amounts and must therefore store them, as well as the produced chemical waste before disposal. Acting as a warehouse, the storage facility also shelters the chemicals: it protects the personnel and the environment from the effects of a spill, or an aerosol or gas emission. While designing a chemical storage facility, regardless of its size, it is thus essential to take into account all hazardous properties of chemicals, intrinsic or arising from interactions (OSHwiki, 2017). 1. Chemical Storage Proper chemical storage is as important to safety as proper chemical handling. Often, seemingly logical storage ideas, such as placing chemicals in alphabetical order, may cause incompatible chemicals to be stored together. The primary purpose of this plan is to control health or physical hazards posed by chemical compounds during storage in the lab (TSU, 2014). 2. Inventory and Inspection Each laboratory is to maintain an inventory of the chemicals stored in the laboratory as part of the lab safety plan. Designate a storage place for each chemical and return it to that place after each use. Store chemicals by hazard class, not the alphabet, and post storage areas to show the exact location of the chemical groups. Inspect chemical storage areas at least annually for outdated or unneeded items, illegible labels, leaking containers, etc. Examples of chemicals in poor condition, that you should NOT keep stored in your lab: Expired/outdated chemicals Illegible/removed labels Degraded containers Leaking lids Proper sealing of Chemical containers To prevent leakage, odors, or reaction with air, tightly seal all containers of highly toxic, highly volatile, malodorous, carcinogenic or reactive chemicals. Make sure that caps and other closures are tight on all hazardous chemicals. A limited exception is freshly-generated mixtures such as acids and organics that may generate gas pressure sufficient to burst a tightly sealed bottle. Use commercially available vent caps or keep the lids loose until sufficient time passes to complete the reactions, and then tightly close the lids. Until all reactions are completed, the contents of the bottle are not waste, but are instead the last step of the chemical procedure. The best seal is the screw cap with a conical polyethylene or Teflon insert. Seal the caps with tape or Parafilm “M” as a further precaution. Additional protection can include wrapping the container in an absorbent paper, sealing it inside a plastic bag, and storing the bag inside a metal can with a friction fitting lid. Smaller Container size The real, or “life-cycle”, cost of a chemical includes its initial purchase price plus the ultimate disposal costs. Keep the quantity of accumulated chemicals in the laboratory at a minimum to reduce the risk of exposures, fires, and waste disposal problems. Smaller package sizes provide the following advantages: Reduced storage hazards Reduced storage space Safety in handling smaller quantities  Reduced losses due to out-of-date chemicals Minimized cost of disposal of “leftovers” Frequently, it costs many times more than the original purchase price to dispose of leftover chemicals. Chemical storerooms on campus keep supplies of the most frequently used solvents and chemicals to lessen the need for laboratory stockpiles. Storage Symbols Most chemical manufacturers include chemical storage symbols on their labels. Many manufacturers use symbols that include a hazard ranking system, such as the National Fire Protection Association (NFPA 704) diamond symbol or the Hazardous Materials Identification System (HMIS) colored rectangle. Picture glyphs are another common label element. Color Codes Some chemical manufacturers also use color codes on labels and/or caps to indicate health, physical, and chemical hazards. These colors can be used as a guide for storage groups store same colors together, segregate from other colors. Unfortunately, the color schemes are not always consistent among manufacturers. Under most schemes, colors convey the following message: Red Fire Hazard and/or Flammables White Contact Hazard and/or Corrosive (acids or bases) Blue Health Hazard and/or Toxic or Poisonous Yellow Reactivity Hazard and/or Oxidizers Green, Gray or Orange Moderate or slight hazard (general chemical storage) Striped or “Stop” Exceptions within the same color code labels (example – yellow label chemicals are stored apart from striped yellow label chemicals) Chemical Storage Locations Optimally, incompatible chemicals such as acids and alkalis should be stored completely separate from one another to prevent mixing in the event of an accidental spill or release of the materials. Limited storage space within the laboratories, however, sometimes prevents such prudent practice of chemical segregation and storage. If space is limited, you can store incompatible chemicals in the same storage cabinet if you segregate the chemicals according to their hazard class and you store them in tubs, trays, or buckets while in the cabinet. These secondary containers reduce the chance that incompatible chemicals will inadvertently contact each other.  a. Laboratory Hoods. Do not store chemicals in laboratory hoods because the containers may impede airflow and thereby reduce the effectiveness of the hood. b. Refrigerated Storage. Store flammable solvents that require storage at reduced temperature (such as isopentane) in refrigerators or freezers designed for storage of flammable liquids. “Safety” refrigerators for flammable liquid storage and “explosion proof” refrigerators are both acceptable. Ordinary household refrigerators are not appropriate for storage of flammable liquids because of interior arcing contacts. Because refrigerators and freezers have no interior space venting, all chemicals should have tightly sealed caps. Apply signage to the doors of chemical refrigerators stating: NO FOOD, BEVERAGE, OR ICE FOR HUMAN CONSUMPTION. Cold rooms have closed air circulation systems that re-circulate escaped vapors within the chamber. The refrigeration coils in cold rooms are aluminum and subject to damage from corrosive atmospheres. The electrical systems normally have vapor proof lights and duplex outlets, but added-on extension cords and plug strips compromise these safety features. Cold rooms are not acceptable for storage of flammables, dry ice, highly toxic liquid chemicals, or compressed gases. If you must refrigerate these chemicals, store them in an approved refrigerator or freezer, rather than a cold room. Post a hazard information sign on the cold room door as illustrated. Storage by Compatibility Group Store chemicals in the laboratory according to their compatibility groups. Do not store chemicals in alphabetical order, as this might place incompatible chemicals next to each other (examples include acetic acid and acetaldehyde, sodium cyanide and sulfuric acid, sodium borohydride and sodium chlorate), increasing the potential for accidental mixing of incompatible chemicals. The diagram entitled “Suggested Shelf Storage Pattern” indicates a recommended arrangement of chemicals according to compatibility. These compatibility groups should be stored separately, especially chemicals with an NFPA 704 or HMIS reactive rating of 3 or higher, (see Section IV) and in dedicated and labeled cabinets. Within any compatibility group, you can arrange chemicals alphabetically to facilitate ease of retrieval. The following are recommended compatibility groupings: 1. Group A – Acids, Inorganics Store large bottles of acid in special acid cabinets, cabinets under lab benches, or on low shelves. Place acids in plastic trays for secondary containment in case of breakage. Segregate inorganic and oxidizing acids from organic compounds including organic acids (e.g., acetic acid) and other combustible materials. Segregate nitric acid (>40%) from organic chemicals, including organic acids. Store acids separate from bases and other reducing agents. Inorganic salts, except those of heavy metals, may be stored in this group. Glacial acetic acid should be stored with flammable and combustible materials since it is combustible. 2. Group B – Bases Segregate bases from acids and oxidizers on shelves near the floor. The preferred storage container for inorganic hydroxides is polyethylene instead of glass. Place containers in trays for secondary containment in the event of leakage or breaks. 3. Group C – Organic chemicals  Segregate organic compounds from inorganics. Organics and inorganics with NFPA 704 or HMIS reactive hazard rating of two (2) or less may be stored together. Chemicals with a reactive hazard rating of three (3) or four (4) are to be stored separately. 4. Group D – Flammable and Combustible Organic Liquids Flammable and combustible liquid storage per room is limited to 10 gallons (37.9 liters) in open storage and use, 25 gallons (94.7 liters) in safety cans, and 60 gallons (227.3 liters) in flammable storage cabinets. Remember that only 30 gallons (113.6 liters) of Class I liquids are permitted per room, and International Fire Code restrictions might limit this even further if your lab is located on an upper floor in a new or renovated building. Store flammable and combustible materials away from sources of ignition such as heat, sparks, or open flames, and segregated from oxidizers. 5. Group E – Inorganic Oxidizers and Salts Store inorganic oxidizers in a cool, dry place away from combustible materials such as zinc, alkaline metals, formic acid, and other reducing agents. Inorganic salts may also be stored in this group. Store ammonium nitrate separately. 6. Group F – Organic Peroxides and Explosives Peroxides contain a double-oxygen bond (R1-O-O-R2) in their molecular structure. They are shock and heat sensitive (e.g. benzoyl peroxide), and readily decompose in storage. Store shock and heat-sensitive chemicals in a dedicated cabinet. Some non-peroxide chemicals can readily form shock-sensitive, explosive peroxides when stored in the presence of oxygen. Examples include ethyl ether, tetrahydrofuran, and cumene. Dispose of, or use, these by their expiration date. Common explosive compounds include 2,4,6-trinitrotoluene (TNT), nitroglycerin, and several metal fulminates and azides. 2,4,6-trinitrophenol, also known as picric acid, is normally sold as a saturated solution containing at least 40% water, and classified as a flammable solid. If allowed to dry to less than 10% water, picric acid becomes a DOT Class 1.1 explosive. Nitroglycerin in research is usually sold as a tincture mixed with alcohol, but if the alcohol evaporates, the result is explosive nitroglycerin. Please contact EHS if you use or handle compounds that are explosive or can become explosive with age or evaporation. 7. Group G – Reactives a. Water Reactives Store water reactives in a cool dry place protected from water sources. Alkali metals (lithium, sodium, potassium, rubidium, and cesium) should be stored under mineral oil, or in waterproof enclosures such as glove boxes. A Class D fire extinguisher should be available in case of fire. Contact EHS if one is not available in your laboratory. As an added precaution, store containers in trays or other secondary containers filled with sand. b. Pyrophorics (Air Reactives) Store pyrophorics in a cool, dry place, and provide for an air tight seal. Store white or yellow phosphorous under water in glass stoppered bottles inside a metal can for added protection. 8. Group H – Cyanides and Sulfides Cyanides and sulfides react with acids to release highly toxic gases. They must be isolated from acids and other oxidizers.  9. Group I – Carcinogens, Highly Toxic Chemicals, and Reproductive Toxins A dedicated lockable storage cabinet in a “designated area” for carcinogens and highly toxic chemicals is the preferred storage method. Stock quantities of reproductive toxins are to be stored in designated storage areas. Use unbreakable, chemically resistant secondary containers. Post the storage cabinet with a sign stating “CANCER SUSPECT AGENT”, “HIGHLY TOXIC CHEMICALS”, or “REPRODUCTIVE TOXINS”. These signs are available at the EHS Safety Labels Page. Maintain a separate inventory of all highly acute toxics, carcinogens, and reproductive toxins (UNC, 2018). CHEMICAL WASTE Chemical waste comes in many different forms and can cause costly damage to structures and the health of those using a contaminated site. Chemical waste is extremely dangerous and can be safely managed by experts. Types of Chemical Waste: Toxic Waste Radioactive Waste Acid Disposal Plastic Disposal Sewage Disposal Waste Sludge KEYWORDS: 1. Accident is defined as an unplanned event leading to undesired consequences. 2. Acute toxicity describes the adverse effects of a substance that result either from a single exposure or from multiple exposures in a short period of time (usually less than 24 hours). 3. Biohazard is a biological substance that poses a threat to the health of living organisms, primarily humans. This could include a sample of a microorganism, virus or toxin that can adversely affect human health. 4. Carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis, the formation of cancer. 5. Chemical laboratory safety is the control of exposure to potentially hazardous substances to attain an acceptably low risk of exposure. 6. Chronic toxicity is the development of adverse effects as the result of long term exposure to a toxicant or other stressor. 7. Corrosives are chemicals which cause burns on the skin, mucous membrane and eyes. 8. Dermatotoxin is a toxic chemical that damages skin, mucous membranes, or both, often leading to tissue necrosis. 9. Explosive is a solid or liquid chemical which is in itself capable by chemical reaction of producing gas at such a temperature and pressure and at such a speed to cause damage to the surroundings. 10. Flammable are gases, liquids and solids that will ignite and continue to burn in air if exposed to a source of ignition. 11. Flash point is the minimum temperature at which a liquid gives off enough vapor to form an ignitable mixture. 12. Fume Hood is a ventilated enclosure in which gases, vapors and fumes are contained. An exhaust fan situated on the top of the laboratory building pulls air and airborne contaminants through connected ductwork and exhausts them to the atmosphere. 13. GHS stands for Globally Harmonized System. It is a system for standardizing and harmonizing the classification and labeling of chemicals. 14. Hazard is defined as a chemical or physical condition that has the potential for causing damage to people, property, or the environment. 15. Hematotoxins are toxins that destroy red blood cells, disrupt blood clotting, and/or cause organ degeneration and generalized tissue damage. 16. Hepatotoxin is a toxic chemical substance that damages the liver. 17. Incident is the unexpected release of a substance that is (potentially) hazardous either to humans, other animals or the environment. 18. LC50 stands for "Lethal Concentration". LC values usually refer to the concentration of a chemical in air but in environmental studies it can also mean the concentration of a chemical in water. The concentrations of the chemical in air that kills 50% of the test animals during the observation period is the LC 50 value. 19. LD50 stands for "Lethal Dose". LD50 is the amount of a material, given all at once, which causes the death of 50% (one half) of a group of test animals. The LD 50 is one way to measure the short-term poisoning potential (acute toxicity) of a material. 20. Nephrotoxin is a toxic agent or substance that inhibits, damages or destroys the cells and/or tissues of the kidneys. 21. Neurotoxins are toxins that are destructive to nerve tissue (causing neurotoxicity). 22. Oxidizers are solid, liquids or gases that react readily with most organic material or reducing agents with no energy input. 23. PPE stands for Personal Protective Equipment. It refers to any equipment worn to minimize exposure to hazards that cause serious workplace injuries and illnesses. 24. Pyrophoric are substances that ignite instantly upon exposure to oxygen, they can also be water reactive, where heat and hydrogen (a flammable gas) are produced. 25. Risk is defined as a measure of human injury, environmental damage, or economic loss in terms of both the incident likelihood (probability) and the magnitude of the loss or injury (consequence). 26. Safety Data Sheet is a document produced in alignment with the UN’s Globally Harmonized System of Classification and Labelling of Chemicals (GHS) that the manufacturer, importer, or distributor of a chemical product is required to provide to downstream users. An SDS needs to have a specific 16- section format, and the process of creating a properly formatted SDS is known as SDS authoring. 27. Toxic are substances that can cause harmful effect to the environment and hazardous to human health if inhaled, ingested, or absorbed through the skin. REFERENCES 1. Geiser, K. (2015). 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Retrieved October 11, 2018, from Uvm.edu: http://www.uvm.edu/safety/lab/general-laboratory-ventilation 47. WHO Human Health Risk Assessment Toolkit: Chemical Hazards. 2010. Available at Work, Geneva 1993 http://www.who.int/ipcs/methods/harmonization/areas/ra_toolkit/en/index.html 48. Work Safe New Zealand (2018). Retrieved October 11, 2018, from WorkSafe: https://worksafe.govt.nz/topic-and-industry/dust-andfumes/fumes/localexhaust- ventilation-quick-guide/ 49. World Health Organization (ND). Chemical hazards. Retrieved from http://www.who.int/ceh/risks/cehchemicals/en/ 50. Zacharia, J.T. (2011). Identity, physical and chemical properties of pesticides. Retrieved from http://cdn.intechopen.com/pdfs/20983/InTechIdentity_physical_and_chemical_prop erties_of_pesticides.pdf Prepared by: ENGR. ARNEL N. BEN Assistant Professor College of Engineering Sultan Kudarat State University