Chemical Safety PDF

CHEMISTRY FOR ENGINEERS Module 4 Chemical Safety Hi, you are almost at the end of your Chemistry for Engineers journey! For this module, you will be introduced with a very essential mindset of an engineer: Safety. Here, you will learn a...

CHEMISTRY FOR ENGINEERS Module 4 Chemical Safety Hi, you are almost at the end of your Chemistry for Engineers journey! For this module, you will be introduced with a very essential mindset of an engineer: Safety. Here, you will learn about chemical safety and the different methods in assuring a safe working environment when dealing with chemical hazards. Upon completion of this module, you are expected to be able to: Recognize the hazards of different chemicals and assess risks of exposure. Identify different measures in controlling chemical exposures. To ensure the achievement of the learning outcomes, this module is organized into two lessons listed as follows: Lesson 1: Chemical Hazards and Risks Lesson 2: Controlling Exposure and Emergency Preparedness 1|Page MODULE 4  CHEMISTRY FOR ENGINEERS Lesson 1: Chemical Hazards and Risks Learning Outcomes: Having successfully completed this lesson, you will be able to: ✓ define chemical safety ✓ recognize chemical hazards and its risk; and ✓ identify routes of exposure of toxic chemicals and exposure toxicity Time Frame: 3 hours Introduction Chemicals are everywhere. Every manufactured product involves the use of chemicals. Even in your homes, you encounter chemicals while cleaning your house, in dealing with your personal hygiene and even in cooking. So, how will you know that a certain chemical is safe to use or not? In this lesson, you will learn what chemical safety is and the hazards and risk in dealing with chemicals, especially hazardous chemicals. Let’s Get Started! 2|Page MODULE 4  CHEMISTRY FOR ENGINEERS Activity #1: Instructions: Lists down household chemicals that you have encountered before and specify on how you handled them and its possible harmful effect to you if you haven’t handled them properly.. YOU CAN DO THIS! List of household Ways of handling the Harmful effects if not chemicals or substances materials handled properly Some of you may not be aware that you constantly handled chemicals in your daily living. For example, in simply taking a bath, you use soap to clean your body. What happens when the soap goes into your eyes? You may feel a stinging pain in your eyes which is actually caused by the surfactants common in soaps, even in shampoos. Rubbing your eyes might worsen the situation and all you can do is to flush your eyes with cool clean water. However, are all chemicals harmful? When can it be considered as safe or harmful? How can it get to you? Is the chance of getting you harm high or low? Let’s Explore! 3|Page MODULE 4  CHEMISTRY FOR ENGINEERS What is Chemical Safety? 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 (WHO, 2020). The first principle of chemical safety is to recognize the hazards of chemicals, equipment, and procedures of handling them. (ACS, 2016) What is hazard and risk? ACS (2016) states that Hazard is any source of potential damage or harm to an individual’s health or life under certain conditions, whether at work or in the home. Risk is the chance or probability of a person being harmed or experiencing an adverse health effect if exposed to a hazard. Risk assessment is the process of estimating the probability of harm from a hazard (the severity of the hazard multiplied by the probability of exposure to the hazard). Table 4.1 shows the four types of hazards and its possible effects. (Source: ACS (2016). Guidelines for Chemical Laboratory Safety in Secondary Schools. Washington DC: American Chemical Society) In our previous example, when soap goes into your eyes while taking a bath, the type of hazard is a substance which is the soap. The potential harm is the stinging pain in the eyes. What is the risk of this from happening? Since we take a bath everyday, chances would be high but the risk could be reduced if we are already careful not to put it in near into our eyes or use a tear-free soap. What type of hazards can chemicals present? In school, mostly we may encounter these inside the chemistry laboratory. ACS (2016) states the following are common laboratory hazards: a. Chemical Hazards Corrosive chemicals - typically, strong acids and bases, solutions with a pH < 2 or a pH > 12 Flammable chemicals - chemicals that are easily ignited or explode under usual laboratory working conditions, such as aldehydes, ketones, and hydrocarbons. 4|Page MODULE 4  CHEMISTRY FOR ENGINEERS b. Physical Hazards Incompatible chemicals for storage or handling - Storing strong oxidizers, such as nitric acid, with reduced compounds, such as hydrocarbons. Reactants that react with air or water, such as alkyl metals or acid halides. Compressed gases and high-pressure systems - This includes both the chemical hazard of the gases and the physical hazard of all parts of the system subjected to greater than 1 bar (>100 kPa). Electrical hazards - Avoid spark sources near solvents. Electrical cords/ cables should not obstruct work or aisles. Extension (“drop”) cords only for short-term use; power strips can be used long-term. Discard and replace damaged cords. c. Reaction hazards Reactive and unstable chemicals - Chemicals that react with air or water require special handling to address their reactive hazards d. Health Hazard Toxic substance - Any substance that has the capacity to produce personal injury or illness to humans through ingestion, inhalation, or absorption through any body surface. classifications such as “highly toxic”, “acutely toxic”, “chronically toxic”, carcinogens, allergens, mutagens, and teratogens. Carcinogens - A substance that is capable of causing cancer. (e.g. Ethylene oxide, Cr(VI) formaldehyde, arsenic) Allergens - A chemical that causes an allergic reaction— that is, evokes an adverse immune response (could be a severe rash or respiratory distress). Mutagens - A substance capable of changing genetic material in a cell and thus increasing the frequency of mutations. (e.g. Mercury, lead, acetone, carbon disulfide) Teratogens - An agent that can cause non-inheritable genetic mutations or malformations of an embryo or fetus. The agent can be a chemical substance, virus, or ionizing radiation. (e.g. Ethanol, ethylene oxide, mercury compounds) Nanomaterials - small size of nanomaterials allows these materials to enter deeply into the respiratory tract or to penetrate unprotected skin. Chemicals that cause physical or health threats to workers in but not limited to clinical, industrial, and academic laboratories are referred to as hazardous chemicals. Hazards caused by these chemicals are those related to the storage, transfer, production or use of chemicals (WSO, 2005). 5|Page MODULE 4  CHEMISTRY FOR ENGINEERS A hazardous material is anything that is: flammable, corrosive, reactive, an oxidizer, toxic/carcinogenic/etc., or breaks down to give species with any of the above categories. Examples: acetone (flammability); hydrochloric acid (corrosive); sodium cyanide (toxicity); chloroform (cancer suspect agent). So how do toxic materials enter the body? The way in which a chemical substance enters the body is called the route of entry/exposure or ROE (ACS, 2016). Fig. 4.1 Routes of exposure (Source: image Retrieved from https://riskmanagement.unt.edu/hcs-ghs-module2) According to UNT Risk Management Services (2020), the four major routes in which chemicals can enter the body are: 1. Inhalation: The taking in of substances through breathing. This is the most common exposure pathway and considered the most since the lungs provide a direct pathway to the bloodstream. 2. Ingestion: The taking in of substances through consumption. This often occurs through poor handwashing practices followed by touching the face or mouth. 3. Absorption: The taking in of substances through the skin or mucous membranes such as the eyes. 4. Injection: The taking in of substances when a sharp object (ex: needle) punctures the skin and transfers the substance into the bloodstream. When these hazardous substances enters into your body, this may lead to toxicity. Toxicity is the ability of a substance to produce an unwanted effect when the chemical reached a sufficient concentration at a certain site of in the body. WSO (2005) stated that chemical toxicity entails both the quantity or amount of chemicals (or dose) and the degree of exposure. Once a military surgeon and alchemist known as Paracelsus wrote, “What is it that is not poison? All things are poison, and nothing is without poison. It is the dose only that makes a thing not a poison.” 6|Page MODULE 4  CHEMISTRY FOR ENGINEERS Exposures to these chemicals may cause acute or chronic effects: Acute toxicity – Short-term exposure to high concentration with an immediate effect. (example: isocyanates, hydrogen sulfide, oxygen deficiency) Chronic toxicity – effect manifests over a period of time. (example: asbestos, arsenic, mercury) Effects of these toxicity to a person may either be local or systemic. Local effects - when a certain chemical harms only a part of a body it contacts with (example: skin burns by acidic chemicals) Systemic effects - when it harms other related organs operating as a system (example: carbon monoxide poisoning which affects the blood and central nervous system). In general, factors affecting the degree of risk from a potential chemical hazards are the dosage, duration of exposure, route of entry and individual susceptibility. Checking your Understanding! Instructions: Fill in the squares with the words described. 7|Page MODULE 4  CHEMISTRY FOR ENGINEERS Down Across 2. taking in of substances through 1. chance or probability of a person being consumption harmed 3. strong acids and bases 4. source of potential damage or harm 5. concentration of chemicals 8. cause malformations of an embryo or fetus 6. chemicals that has the capacity to 9. effect manifests over a period of time produce personal injury or illness 7. capable of changing genetic material in 10. most common pathway of exposure a cell Well done! As the saying goes, “The chemicals don’t know what laboratory they are in.” Learning to recognize the hazards and assess the risk of these chemicals will help you minimize its harmful effects. In the next lesson, we will discuss the different ways of controlling exposures so we may ensure our safety when dealing with chemicals. Let’s be safe, okay? 8|Page MODULE 4  CHEMISTRY FOR ENGINEERS Lesson 2: Controlling Exposures and Emergency Preparedness Learning Outcomes: Having successfully completed this lesson, you will be able to: ✓ Identify the different types of hierarchy of controls in controlling exposures to hazards. ✓ Recognize the chemical hazards and its risk by identifying the GHS pictograms and use of Safety data sheets; and ✓ Know how to respond in case of emergencies involving chemicals Time Frame: 3 hours Introduction Chemicals by nature are mostly harmful especially when you are exposed into it beyond its permissible exposure limit. Even if you may want to avoid it, you can never will. Chemicals are an integral part of life, and the most you can do about it is to manage it properly and provide necessary control measures to minimize if not eliminate its harmful effect. Let’s Get Started! 9|Page MODULE 4  CHEMISTRY FOR ENGINEERS Activity #2: Laboratory safety gone wrong! Instructions: Look at the picture below and answer the following questions: Fig, 4.2. Laboratory safety. (Source: Smith, B. (2018). Lab Safety [image]. Retrieved from https://smithb7science.weebly.com/biology-class/lab-safety) 1. Identify the good and bad practices you can see in the scenario above. 2. What can be done to correct the unsafe activities? Let’s Think About it! Activity # 2: Insight In addressing safety in any workplace, here are the five key questions that you might ask and answer: (Sigmann, S.; Stuart, R. (2016) 1. What specific chemical or physical reactivity hazards are associated with the way I’m using these chemicals? 2. What type of ventilation do I need? 3. What personal protective equipment do I need? 4. What emergency response protocols will be needed if something goes wrong? 5. What will I do with the waste? Although most chemicals itself is harmful by nature, we can still ensure its safe use by controlling exposure. How can we do this? 10 | P a g e MODULE 4  CHEMISTRY FOR ENGINEERS Controlling Exposure A hierarchy of controls is used as a means of determining how to implement feasible and effective controls. Figure 4.3 Hierarchy of Controls (Source: ACS (2017). Safety in Academic Chemistry Laboratories, 8th ed. Washington DC: American Chemical Society) Elimination/Substitution The most desired method of control is the elimination or substitution but is the hardest to do and most expensive way. In Fig. 4.4, safer choice is to have pellets or paste instead of powdered substances which readily produce high levels of dangerous dusts. Fig. 4.4. Chemical substitution. (Source: image retrieved from https://www.ilo.org/legacy/english/protection/safework/cis/products/safetytm/intro duc.htm) 11 | P a g e MODULE 4  CHEMISTRY FOR ENGINEERS Engineering Controls Engineering controls must be the primary means to reduce the exposure of chemicals. This includes certain modifications in the equipment being used or providing control measures. Fig. 4.5 Use sealed pipes to transfer solvents and other liquids instead of pouring them in the open air. (Source: image retrieved from https://www.ilo.org/legacy/english/protection/safework/cis/products/safetytm/intro duc.htm) Figure 4.6 Use of fumehoods in the laboratory. (Source: image retrieved from https://blushzila.com/2019/03/09/quick-tips-for-working-with-the-fume-hoods/) 12 | P a g e MODULE 4  CHEMISTRY FOR ENGINEERS Fig. 4.7 Straps and closed storage for gas cylinders. (Source: image retrieved from https://www.globalindustrial.com/p/stora ge/flammable-osha- cabinets/cylinder/durham-vertical-gas- cylinder-storage-cabinet-holds-nine- vertical-cylinders-up-to-5975-tall) https://inside.ewu.edu/ehs/laborator Administrative and Work Practice ies-and-shops/laboratory- Controls safety/chemical-safety/. This may be appropriate in some cases where engineering controls cannot be implemented. This may involve the use of standard operating procedures and proper labeling of chemicals. Chemical Hygiene Plan A Chemical Hygiene Plan (CHP) is a set of documents describing the types of hazards present in a department or laboratory and what procedures and precautions are used to promote safety while working with the hazards (EWU EHS, 2020). Always read laboratory rules and regulations, operating procedures or safety manual first before starting work. Perform chemical inventory regularly. Engage persons handling chemicals with proper trainings. Fig. 4.8 Chemical Hygiene Plan. (Source: EWU EHS (2020). Chemical Safety [image]. Retrieved from https://inside.ewu.edu/ehs/laboratories-and-shops/laboratory- safety/chemical-safety/) 13 | P a g e MODULE 4  CHEMISTRY FOR ENGINEERS Use of Safety Data Sheets (SDS) Table 4.2 SDS Section Numbers and Headings. (Source: ACS (2016). Guidelines for Chemical Laboratory Safety in Secondary Schools. Washington DC: American Chemical Society) Table 4.2 shows the 16 sections that must be included in SDS.The Safety Data Sheet (SDS), formerly known as the Material Safety Data Sheet (MSDS), is a document for each chemical to give information on its hazards. Before using a certain chemical, read the SDS first to understand the type of chemical you are handling, the exposure controls, disposal considerations, and emergency preparedness you might need with it. Globally Harmonized System on Labeling of Chemicals ACS (2016) states that the Globally Harmonized System (GHS) is an internationally adopted system for the classification and labeling of hazardous chemicals. It includes established criteria for classifying hazards and for further categorizing (or rating) the hazards according to their relative risks. Fig. 4.9 GHS Pictograms. (Source: ACS (2017). Guidelines for Chemical Laboratory Safety in Secondary Schools. Washington DC: American Chemical Society) 14 | P a g e MODULE 4  CHEMISTRY FOR ENGINEERS Proper Labeling of Chemicals Label everything. Don’t allow materials to become unknowns. Fig. 4.10 GHS compliant label. (Source: UNT EHS (2020). Labeling [image]. Retrieved from https://riskmanagement.unt.edu/hcs-ghs-module3) The following explains each of the numbered sections of the GHS label example. 1. Signal Word – This indicates the level of hazard associated with the chemical. “Warning” can also be used which would indicate a less severe hazard. 2. Pictogram – Identifies visually the hazards associated with the chemical. 3. Manufacturer Information – Name, address, phone number. 4. Precautionary Statements/First Aid – Each statement is tied to a hazard statement and gives information regarding preventative measures and basic first aid. 5. Hazard Statements – Phrases that describe the hazards and severity of the chemical. Each of these are assigned an H-code, which can be referenced. Good Practices (Standard Operating Procedures) The following are some good practices that can be done to minimize risk from chemicals. Obtain the minimum amounts of chemicals needed for your work. Never mouth-pipet. Use aspirator or rubber bulb when using pipet. When smelling, use your hand to waft vapors toward your face and sniff gently. Do not left any work or equipment unattended. Always dilute concentrated acids by adding the acid Fig. 4.11 Wafting when to water, never the reverse. smelling chemicals 15 | P a g e MODULE 4  CHEMISTRY FOR ENGINEERS Always leave benches, balances, and other equipment clean & tidy after use. Practice 5S. Good housekeeping is the key to a safe workplace. Never perform work with chemicals without permission or authorization. Behave and observe proper behavior when handling with chemicals. No horseplaying and focus on your work. Fig. 4.12 No It is advisable not to wear jewelries when handling dumping of chemicals chemicals Do not dispose chemicals down the drain after use. down the sink Dispose of used chemicals as instructed. If unsure, ask for guidance. Fig. 4.11 & 4.12. (Source: EWU EHS (2020). Chemical Safety. Image Retrieved from https://inside.ewu.edu/ehs/laboratories-and-shops/laboratory- safety/chemical-safety/) Proper Storage of Chemicals Many chemicals are incompatible with each other. Some may react with each other violently and may release toxic gases. Proper care should be taken when handling, storing and disposing of combination of chemicals. Proper storage of chemicals must be based on its properties, not alphabetical. Use of secondary containment is also recommended. When at home, keep chemicals away from the reach of children. Fig. 4.13 Chemicals compatibility storage groups. (Source: Vanderbilt EHS (2020 July). Managing Chemical Retention and Storage[image]. Retrieved from https://www.vumc.org/ safety/chem/managing- chemical-retention- and-storage) 16 | P a g e MODULE 4  CHEMISTRY FOR ENGINEERS Personal protective equipment (PPE) PPE, though commonly used, is the least desirable but may still be effective. This include but not limited to the use of laboratory coats/gowns, coveralls, goggles, face shields, closed shoes, gloves and face mask. PPE used must be appropriate according to the chemical hazard to be controlled, environment, and must be fit to the person using it. Fig. 4.14 Use of personal protective equipment. (Source: image retrieved from https://www.ilo.org/legacy/english/protection/safework/cis/products/safetytm/intro duc.htm) Emergency Preparedness Even if the chemical hazards are appropriately managed, incidents may still happen. It is important for you to know how to respond to chemicals spills, fires and accidents. Joining emergency drills is an advantage. Evacuation Plan/Route One of the things to consider when entering a new place is to take a look at its evacuation plan. You must learn to know where the entrance and emergency exits are located just in case an emergency happens. Be familiar with the place where you are at. Fig. 4.15 Evacuation Route 17 | P a g e MODULE 4  CHEMISTRY FOR ENGINEERS Fire Extinguishers Some chemicals are flammable and some chemicals when combined together may cause an explosion. You better know the location of fire extinguishers and learn how to use them, just in case of small fires. But in case of a larger fire, do not attempt to extinguish the fire by fire extinguisher, it will be totally useless. Immediately evacuate the area, do not play superhero. Fig. 4.16 How to use a fire extinguisher. In case your clothes are on fire, do not run but instead do the this: Fig. 4.17 When you are on fire. Fig. 4.15-19. (Source: ACS (2017). Guidelines for Chemical Laboratory Safety in Secondary Schools. Washington DC: American Chemical Society) Emergency Showers and Eyewash In case of chemical contamination on skin, clothing and eyes, immediately flush the contaminated area with water for at least 15 minutes. Except the eyes, you may wash the area with soap and water. Seek medical attention after for further check-up. Fig. 4.18 Eyewash Emergency Alarm In case of emergency, if you are trained or familiar with it, you may activate the emergency alarm to inform others. Chemical Spills In case of chemical spills, control the spill of liquid with special absorbent material. For solids, collect and contain residues and place them in a plastic bag or bucket. For acids, neutralize with base and vice versa. Dispose of chemicals accordingly (ACS, 2016). However, when Fig. 4.19 Chemical chemical spills happen in school laboratory, inform your Spill teacher. Let those laboratory in-charge handle the spill, do not do it yourself. 18 | P a g e MODULE 4  CHEMISTRY FOR ENGINEERS Broken Glassware Handle broken glassware with gloves. If it occurs in the school, students are not allowed to clean it up, let your teacher do it. If a dangerous chemical is on the glassware, treat the glassware as contaminated and dispose of it accordingly. Checking your understanding: Chemical Safety Scenarios Exercise 4.2 Chemical Safety Scenarios 1. Read the following laboratory scenarios and write down the safe and unsafe practices. Specify the type of controls that can be done to prevent the unsafe acts or conditions. a. Jon broke a test tube. Carefully he picked up pieces with one hand and placed them in her other hand. Then he dumped the glass pieces into the wastebasket. b. The teacher was not in the room yet. Rhea began weighing chemicals, touching them with her hands. Her nose itched so she rubbed it. c. Vincent was heating a test tube. He didn’t put on safety goggles since he was wearing glasses. He slanted the tube away from his work area, but toward students on the opposite side of his lab table. 2. Read the scenario below, in case of emergency, what will you do? a. Your lab experiment involves heating a certain substance in a beaker. Since the electric heater is defective, you opt to use the bunsen burner for heating. After a while, you smell a distinct odor of gas. You decide to tell your teacher but remembered that she was called out to the office by the dean. It will took atleast 10 minutes for her to reach the laboratory. What will you do? b. Upon performing an experiment, two of your groupmates make fun of each other. One of them picked-up the thermometer and accidentally bump it in the table. The thermometer broke and mercury were spilled on the table and on the floor. What will you do? Controlling exposures is a preventive measure and as they say “prevention is better than cure”. But preparing how to respond in case of emergency is just as important. We must remember that safety is everyone’s responsibility. When in doubt, ask. Do not guess. And always carry a lot of common sense with you, especially when dealing with chemicals. 19 | P a g e MODULE 4  CHEMISTRY FOR ENGINEERS References: American Chemical Society (2016). Guidelines for Chemical Laboratory Safety in Academic Institution. Washington DC: American Chemical Society. American Chemical Society (2016). Guidelines for Chemical Laboratory Safety in Secondary Schools. Washington DC: American Chemical Society. American Chemical Society (2017). Safety in Academic Chemistry Laboratories, 8th ed. Washington DC: American Chemical Society. UNT Risk Management Services (2020, July 17). HCS and GHS Training Module 2. Retrieved from https://riskmanagement.unt.edu/hcs-ghs-module2. World Health Organization (2020, July 17). Chemical Safety. Retrieved from https://www.who.int/health-topics/chemical-safety#tab=tab_1. World Safety Organization (2005). Basic Occupational Safety and Health Course. Philippines: World Safety Organization, International Office for Philippines. Smith, B. (2018, Aug 18). Lab Safety. Retrieved from https://smithb7science.weebly.com/biology-class/lab-safety. Sigmann, S.; Stuart, R. (2016). Assessing Risk: Five Key Questions for Safe Research and Demos. inChemistry Magazine, pp 6-9. 20 | P a g e MODULE 4