Chemical Safety Lecture Materials PDF

CHEMICAL SAFETY Overview Accidents with hazardous chemicals can happen quickly and may be quite severe. To prevent this accidents to happen, when using any chemical, even if it is something that you have worked with at home or in other situations, it is important to understand what the hazards may...

CHEMICAL SAFETY Overview Accidents with hazardous chemicals can happen quickly and may be quite severe. To prevent this accidents to happen, when using any chemical, even if it is something that you have worked with at home or in other situations, it is important to understand what the hazards may be and how to work with it safely. In order to assess the hazards of a particular chemical, both the physical and health hazards of the chemical must be considered. The container label and other appropriate sources should be reviewed to determine what conditions of use may pose a hazard. 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. Chemical safety has many scientific and technical components. Among these are toxicology, ecotoxicology and the process of chemical risk assessment which requires a detailed knowledge of exposure and of biological effects. Learning Outcomes: After completion of this unit, students should be able to: 1. Discuss physical and health hazards. 2. Identify the possible routes of entry of hazardous chemicals and enumerate safety precautions and first aids. 3. Identify to stay away as much as possible from some hazardous chemicals. 4. Discuss GHS and their goals. 5. Design a safe and efficient storage of chemicals. 6. Enumerate classes, sources and prevention of unnecessary fire. 7. Deal with chemicals and fire sources safely to avoid accidents and unnecessary fire. Course Materials LESSON 27 Physical and Health Hazards of Chemicals Physical Hazards The physical hazards of a chemical include its flammability and reactivity. Flammability is the tendency of a chemical to burn. The flashpoint, auto ignition temperature and flammable limits of the material may be found in the Safety Data Sheets or SDS, and are helpful in assessing the potential for a fire hazard under specified conditions. Reactivity is the potential of the material to explode or react violently with air, water or other substances upon contact. The SDS furnishes this information in the Stability and Reactivity Data section Possible Routes of Entry 1 Skin and Eye Contact The simplest way for chemicals to enter the body is through direct contact with the skin or eyes. Skin contact with a chemical may result in a local reaction, such as a burn or rash, or absorption into the bloodstream. Absorption into the bloodstream may then allow the chemical to cause toxic effects on other parts of the body. The absorption of a chemical through intact skin is influenced by the health of the skin and the properties of the chemical. Skin that is dry or cracked or has lacerations offers less resistance. Wear gloves and other protective clothing to minimize skin exposure. Symptoms of skin exposure include dry, whitened skin, redness and swelling, rashes or blisters, and itching. In the event of chemical contact on skin, rinse the affected area with water for at least 15 minutes, removing clothing while rinsing, if necessary. Seek medical attention if symptoms persist. Chemical contact with eyes can be particularly dangerous, resulting in painful injury or blindness. Wearing safety goggles or a face shield can reduce the risk of eye contact. Eyes that have been in contact with chemicals should be rinsed immediately with water continuously, for at least 15 minutes. Contact lenses should be removed while rinsing— do not delay rinsing to remove the lenses—seconds count. Medical attention is necessary if symptoms persist. Inhalation The lungs are the most common route of entry for gases, vapors and particles. Such materials may harm tissue in the lungs or enter into the bloodstream. Most chemicals have an odor that is perceptible at a certain concentration, referred to as the odor threshold. Olfactory fatigue may occur when exposed to high concentrations or after prolonged exposure to some substances. This may cause the odor to seem to diminish or disappear, while the danger of over-exposure may remain. Symptoms of over-exposure may include headaches, increased mucus production, and eye, nose and throat irritation. Narcotic effects, including confusion, dizziness, drowsiness, or collapse, may result from exposure to some substances, including many common hydrocarbon solvents. In the event of exposure, close containers, open windows or otherwise increase ventilation, and move to fresh air. If symptoms persist, seek medical attention. Chemicals that produce vapors should be used in a well ventilated area or with local exhaust ventilation. Occasionally, general ventilation may not be adequate and local exhaust ventilation may not be feasible, making it necessary to use a respirator. Ingestion 2  The gastrointestinal tract is another possible route of entry for toxic substances. Although it is unlikely that anyone would accidentally eat a chemical, exposure may occur as a result of eating or drinking contaminated food or beverages or touching the mouth with contaminated hands. The possibility of exposure by this route may be reduced by not eating, drinking, smoking, or storing food in the areas where chemicals are used or stored and by washing hands thoroughly after working with chemicals, even when gloves are worn. In the event of accidental ingestion, immediately go to hospitals. Do not induce vomiting unless directed to do so by a health care professional. Injection The final possible route of exposure to chemicals is by accidental injection. Injection may occur through mishaps with syringe needles, or through accidents with broken glassware or other sharp objects that have been contaminated with chemicals. If accidental injection has occurred, wash the area with soap and water and seek medical attention, if necessary. Cautious use of any sharp object is always critical. Health Hazards of Chemical Exposure When discussing the health effects of chemicals, two terms are often used interchangeably - toxicity and hazard. However, the actual meanings of these words are quite different. Toxicity is the ability of a chemical substance to cause harm. Hazard is the likelihood that a material will cause harm under the conditions of use. Thus, with proper handling, even highly toxic chemicals can be used safely. Conversely, less toxic chemicals can be extremely hazardous if handled improperly. The actual health risk of a chemical depends on the toxicity and the actual exposure. No matter how toxic the material may be, there is little risk involved unless it enters the body. An assessment of the chemical's toxicity and the possible routes of entry will help determine what protective measures should be taken. The affects of a chemical exposure to a person will vary; depending on the actual amount of the chemical to which a person was exposed and how hazardous the chemical actually is. Toxic Effects of Chemicals The toxic effects of a chemical may be local or systemic. Local injuries involve the area of the body in contact with the chemical. For example, if you spill an acid on your arm, the effect will be on your arm. Systemic injuries involve tissues or organs other than the contact site where toxins have been transported through the bloodstream. For example, methanol that has been swallowed may cause blindness. Certain chemicals may affect a target organ. For example, lead primarily affects the brain, kidney and red blood cells and some solvents may harm the liver and kidneys. 3 It is important to distinguish between acute and chronic exposure and toxicity. Acute toxicity results from a single, short exposure. Effects usually appear quickly and are usually reversible. Chronic toxicity results from repeated exposure over a long period of time. Effects are usually delayed and gradual, and may be irreversible. For example, the acute effect of drinking alcohol is becoming drunk, while the chronic effect from drinking alcohol over a long period of time is cirrhosis of the liver. Susceptibility of Individuals Some people may be more or less sensitive to specific chemicals, depending on several factors including eating habits, physical condition, obesity, medical conditions, drinking and smoking, and pregnancy. Over a period of time, regular exposure to some substances can lead to the development of an allergic rash, breathing difficulty, or other reactions. This phenomenon is referred to as sensitization. Over time, these effects may occur with exposure to smaller and smaller amounts of the chemical, but will disappear soon after the exposure stops. For reasons not fully understood, not everyone exposed to a sensitizer will experience this reaction. Examples of sensitizers include epoxy resins, nickel salts, isocyanates and formaldehyde. Particularly Hazardous Substances Carcinogens Many chemicals have been evaluated for their ability to cause cancer. The latency period for most cancers range from twenty to forty years. The risk of developing cancer from exposure to a chemical increases with the length of exposure and with the exposure concentration. It is important to understand the distinction between human carcinogens and suspected human carcinogens. The term human carcinogen is used when there is clear evidence of the ability to cause cancer in humans. Suspected human carcinogen refers to chemicals that have been shown to cause cancer in two or more animal species and are, therefore, suspect in humans. Anyone who works with, or plans to work with carcinogens or suspected carcinogens must follow strict guidelines to minimize exposure. Reproductive Toxins Reproductive toxins are chemicals which affect the reproductive system, including mutagens (those which cause chromosomal damage), teratogens and embryotoxins. Embryotoxins may be lethal to the fertilized egg, embryo or fetus, may be teratogenic (able to cause fetal malformations), may retard growth or may cause post-natal functional deficits. Other reproductive toxins may cause sterility or may affect sperm motility. Some chemicals may cross the placenta, affecting the fetus. A developing fetus may be more sensitive to some chemicals than its pregnant mother, particularly during the first twelve weeks of pregnancy, when the mother may not know she is pregnant. Proper handling of chemicals and use of protective equipment is especially important to reduce fetal exposure to chemicals. 4 Known human teratogens include organic mercury compounds, lead compounds, ionizing radiation, some drugs, alcohol ingestion, and cigarette smoking. Some substances which may cause adverse reproductive effects in males include 1,2-dibromo-3-chloropropane, cadmium, mercury, boron, lead, some pesticides, and some drugs. More than 800 chemicals have been shown to be teratogenic in animal models - many of these are suspected human teratogens. Individuals who work with teratogens and who are contemplating pregnancy or are pregnant should review the toxicity of the chemicals in their workplace and may consult with the doctor to determine whether any of the materials pose additional risk during pregnancy. LESSON 28 Chemical Accidents Consider the following chemical accidents: In June 26, 1997 in Aachen, Germany A teacher lets his class (13 year old children) clean the classroom. To remove writings on the desks they used Ethanol. They didn’t open the window causing a highly explosive air/Ethanol mixture to form. A boy lit a match and the whole classroom exploded. Here,21 children were injured, and 4 had suffered severe burns. Chemical spill that caused a small explosion forced UP Manila to close down laboratory last May 5, 2007 as reported by Allison Lopez First Posted 02:09am (Mla time) MANILA, Philippines. A seven-month-old baby in General Santos City was hospitalized after her mother mistakenly gave her kerosene to drink, a radio report said Thursday. Radio dzRH reported that the baby felt sick after drinking the kerosene that was placed inside a bottle of mineral water. The child’s mother said she accidentally picked up the container of kerosene, thinking it was water. Accidents do happen whether at home or in the workplace. To avoid such, be mindful of the following discussions. Globally Harmonized System (GHS) Currently many different countries have different systems for classification and labelling of chemical products. In addition, several different systems can exist even within the same country. This situation has been expensive for governments to regulate and enforce, costly for companies who have to comply with many different systems, and confusing for workers who need to understand the hazards of a chemical in order to work safely. GHS stands for the Globally Harmonized System of Classification and Labelling of Chemicals. GHS defines and classifies the hazards of chemical products, and communicates health and safety information on labels and safety data sheets. The goal is that the same set of rules for classifying hazards, and the same format and content for labels and safety data sheets (SDS) will be adopted and used around the world. GHS promises to deliver several distinct benefits. Among them are: 5  Promoting regulatory efficiency. Facilitating trade. Easing compliance. Reducing costs. Providing improved, consistent hazard information. Encouraging the safe transport, handling and use of chemicals. Promoting better emergency response to chemical incidents. Reducing the need for animal testing. Harmonised criteria for the classification for physical, health, and ecological hazards Harmonised communication with regard to ✓ hazardous substances labelling, ✓ material safety data sheets, ✓ transport labelling of dangerous goods, ✓ occupational health and safety, and ✓ consumer protection. The GHS standardized the labelling of chemicals as follow: 6 Storage of Laboratory Chemicals The following general suggestions for safe storage of chemicals in the laboratory should be implemented. Chemicals must be not be stored alphabetically but MUST be based on their hazard categories The quantities of chemicals that are stored within a laboratory should be minimized. Bulk quantities of chemicals (i.e., larger than one-gallon) must be stored in a separate storage area. Transfer of flammable liquid from 5 gallon or larger metal containers may not be done in the laboratory. Chemicals must be stored at an appropriate temperature and humidity level. This can be especially problematic in hot, humid climates. As a rule, chemicals should not be stored near heat sources, such as steam pipes or laboratory ovens. Chemicals should never be stored in direct sunlight. Chemicals should be dated when received and when opened. If the chemical is one that degrades in quality or becomes unsafe after prolonged storage, the shelf-life expiration date should also be included. Visual inspection of the material and its container should be conducted routinely. Indications for disposal include: o cloudiness in liquids o material changing color o evidence of liquids in solids or solids in liquids o "puddling" of material around outside of container o pressure build-up within bottle o obvious deterioration of container Chemicals should not be routinely stored on the benchtops. In such locations they are unprotected from exposure and participation in a fire situation and are also more readily knocked over. Each chemical should have a specific storage area and be returned there after use. Large quantities of flammable materials should not be stored in the laboratory. Only the amounts needed should be kept on benchtops, the remainder should be kept in flammable storage cabinets. Laboratory shelves should have a raised lip along the outer edge to prevent containers from falling. Never allow the container to hang off the edge of the shelf! Liquid or corrosive chemicals should never be stored on shelves above eye-level. Glass containers should not touch each other on the shelves. Secondary containers or trays should be used for chemical storage whenever possible to minimize the flow of material should a spill or rupture occur. Round bottom flasks should always be supported properly in cork rings or by other means to keep them from tipping. Adequate security must be provided so that unauthorized personnel do not have access to hazardous materials. Chemicals must never be stored on the floor, not even temporarily! Chemicals that are no longer to be used for research purposes should be properly disposed of or given to another research group that has a use for it. 7  Flammable materials must never be stored in domestic-type refrigerators. Only explosion-proof or flammable material refrigerators should be used for storage of these chemicals within a laboratory environment. All containers stored within the refrigerator should be tightly capped to keep vapors from interacting with each other and to alleviate "smell" problems. Flasks with cork, rubber or glass stoppers should be avoided because of the potential for leaking. All containers stored in the refrigerator must be properly labeled. Inventory the materials in your refrigerator frequently to avoid overcrowding with materials that have long since been forgotten. Also make it a point to defrost your refrigerator occasionally so that chemicals do not become trapped in unique ice formations! Before flammable materials are stored in a refrigerator, it should be determined if keeping the material chilled will serve any purpose. No benefit is derived from refrigerating a chemical that has a flash point below the temperature of the refrigerator. Never store peroxide formers (i.e., ether) in a refrigerator! Fume hoods should not be used as general storage areas for chemicals. This may seriously impair the ventilating capacity of the hood. Gas cylinders must be securely strapped to a permanent structure (wall, lab bench, etc.). When they are not in use they should be capped off. On termination, graduation or transfer of any laboratory personnel, all hazardous materials must be properly disposed of, or arrangements made to transfer them to the laboratory supervisor. Segregation Based on Hazard Classes In addition to general safe storage practices, segregated storage of incompatible materials is a must. As a minimum, laboratories should separate chemicals according to similar hazards, such as flammability, corrosivity, sensitivity to water or air, and toxicity. The following major categories of chemicals, are strongly recommended: Flammables Oxidizers Corrosives acids bases Highly Reactives Extreme Toxics/Regulated Materials Low Hazard Most chemicals have multiple hazards and a decision must be made as to which storage area would be most appropriate for each specific chemical. First you have to determine your priorities! When establishing a storage scheme, the number one consideration should be the flammability characteristics of the material. If the material is flammable, it should be stored in a flammable cabinet. If the material will contribute significantly to a fire (i.e., oxidizers), it should be isolated from the flammables. If there were a fire in the lab and response to the fire with water would exaggerate the situation, isolate the water reactive material away from contact with water. Next look at the corrosivity of the material, and store accordingly. Finally, consider the toxicity of the material, with particular attention paid to regulated materials. In 8  some cases, this may mean that certain chemicals will be isolated within a storage area, for instance, a material that is an extreme poison but is also flammable, should be locked away in the flammable storage area to protect it against accidental release. There will always be some chemicals that will not fit neatly in one category or another, but with careful consideration of the hazards involved, most of these cases can be handled in a reasonable fashion. For the safety of all personnel and to protect the integrity of the facilities, hazardous materials must be segregated. All these combinations cause explosions or LESSON 29 FIRE SAFETY Heat can be generated by work processes and is an essential part of some processes such as cooking. This heat must be controlled and kept away from fuel unless carefully controlled. Heat generated as a by-product of a process must be dealt with properly, or else it may bring about unnecessary fire. A fire needs three elements - heat, oxygen and flammable material or fuel. Without heat, oxygen and fuel a fire will not start or spread. A key strategy to prevent fire is to remove one or more of heat, oxygen or fuel. The risk assessment should include detail on all three elements to minimize the risk of a fire starting/ spreading. Common causes of fire Examples of fuel sources in the workplace Paper Textiles (curtains, carpets etc) Rubbish and waste Flammable substances (paint, cleaning materials, solvents) Safety measures to prevent fire Flammable substances should be safely stored away from anything that can cause fire to spread, preferably in a locked cupboard According to Fire and Rescue statistics, the four most common causes of accidental fires in non-dwelling properties were: 1. Faulty appliances and leads Examples of this most common cause of fire include: Frayed wiring Overloaded sockets Old appliances Damaged plugs Faulty appliances Sources of Fire 9 Prevention tips Damaged wiring can overheat and cause sparks. If you spot frayed wiring or overloaded sockets, these need to be replaced/removed. It’s important that appliances are regularly checked by an electrician. Annual portable appliance testing (PAT) needs to be done. Replace any faulty equipment and keep an eye out for any product recalls. 2. Faulty fuel supply Examples include: Gas leaks Electrical supply problem Defective fuel supply to an electrical appliance Leaking fuel e.g. petrol in a garage Prevention tips Regular servicing of all electricity and gas appliances is essential. Make sure everything works correctly, and if not you’ll need to replace with new and safe appliances. Make sure any repair work is carried out by a qualified heating engineer or electrician. Any spills must be cleaned thoroughly, particularly if hot work takes place in your workplace. 3. Misuse of equipment or appliances Examples of this include: Spills on electrical equipment Phones left to charge too long Portable heaters left on Dirty ovens and microwaves Lint tray in tumble dryer Prevention tips Switch off electrical equipment when not in use, at the wall if possible. Unplug if you can. Don’t put something hot near something that can catch fire and keep drinks away from electrical equipment to avoid dangerous spills. In the kitchen, make sure cooking is never left unattended. Keep ovens and microwaves clean, as grease and dirt can cause fires. Toasters often set off the fire alarm unnecessarily so keep these on a low browning setting and regularly empty the crumb tray. Make sure appliances are regularly checked and serviced. Tumble dryers are a common source of fire, so clean the lint tray daily. Keep areas tidy, as dirt and dust on electrical equipment can cause it to overheat. Make sure your building is cleaned regularly 10 4. Placing articles too close to heat Examples include: Tea towel near cooking appliances Candles knocked over Tin foil at bottom of oven Clothes on heater Prevention tips Keep in mind that It’s not just heaters and ovens that generate heat, electrical equipment does too. Ensure paper is placed or stored away from anything that generates heat. Don’t put clothes on heating devices. Avoid using tin foil on or near the bottom of the oven as this can ignite. Common sense is all you need for this one, if it’s something that gets hot, store anything flammable away from it. It’s also important to consider the possibility of arson. Install sprinkler systems where possible, and have CCTV as a deterrent. Don’t give intruders anything they can set fire to; keep rubbish locked away and inaccessible. Before leaving for the day, make sure your building is securely locked, and that all windows are closed. Don’t forget about the dangers of smoking. Keep the smoking area well away from the main building and provide a place for cigarettes to be thoroughly extinguished. Make sure your business has an up-to-date fire risk assessment. This includes a written record of potential sources of ignition, fuel and oxygen and how you can reduce or remove any risks. Fire Extinguishers User’s Guide Familiarize oneself with the location, function and utilization of up to date extinguishers. By keeping your risk assessment up-to-date, and running regular fire safety training, you can keep everyone informed and safe. First Aid during Burns Light burnt: Wash with cold water for 10 min Severe burnt: Put antiseptic & go to the doctor Burnt by acid: Put polyethylene glycol 400 (article no 817003)/calcium gluconate Light wound: Wrap with band-aid 11  Severe wound: Put antiseptic and wrap with band-aid to avoid bleeding Evacuation procedures Go out to a place of safety! Help the handicapped! Don´t run or panic Don´t use elevators because it might get stuck. Go to ground level into the open air! Go to your assembly point! Don’t return to the building unless it’s safe already. Emergency Exits The sign must be clear. Show the way to the closest exit Equipped with emergency lighting. Never locked Free from bags and other equipment. Directly connected to emergency stairs. References: https://ehs.princeton.edu/workplace-construction/occupational-health/chemical-safetyhazard- communication/chemical-safety-concerns https://www.hsa.ie/eng/Topics/Fire/Fire_Prevention/ https://ehs.iupui.edu/lab/guidance/storage/index.html https://www.ccohs.ca/oshanswers/chemicals/ghs.html 12 13