A required reading assignment for all chemistry students

Transcription

1 A required reading assignment for all chemistry students After reading and studying the contents of this packet, all students must take a Lab Safety Quiz and score 90% or higher to become certified to work in the chemistry lab. 1

2 Learning Targets Lab Safety Unit Safety First! Unit Vocabulary Students must have a working knowledge of the following terms: safety glasses eye wash station fire extinguisher fume hood safety shower lab apron fire blanket sodium bicarbonate first aid kit corrosive poisonous test tube flask beaker graduated cylinder Bunsen burner electronic balance hotplate riser (section of lab bench) acid base tap water distilled water volatile waft (technique for smelling) stock container closed system vapor solution reactant / reagent spatula chemical prep room 2

3 What students should know after studying this unit Learning Target 1: Students must know common sense safety rules and regulations for working in the chemistry laboratory. Know Partially Know Don t Know a. Students must know the common sense rules for working in the laboratory as detailed in class, provided in handouts, and posted online as mandatory reading (including but not limited to: wearing safety glasses at all times, tying back long hair and loose sleeves, not eating in the lab, not engaging in horseplay, and not wearing open toe shoes in the lab). b. Students must pass a written lab safety quiz with a 90% or higher score before being allowed to work in the lab. This quiz covers basic lab safety rules, safety equipment, and common lab practices/techniques. Learning Target 2: Students must know the location of and how to properly use laboratory personal safety equipment in the chemistry lab. a. Students must know the location of: eyewash, fire extinguisher, fume hood, safety shower, fire blanket, first aid kit, broken glass disposal box, sodium bicarbonate, broom/hand brush and dustpan, safety glasses, aprons. b. Students must know how and when to use the personal safety equipment listed above (in learning target 2a). Learning Target 3: Students must be able to use laboratory equipment properly. a. Students must be able to properly use an electronic balance, hotplate, and Bunsen burner b. Students must be able to identify common glassware by name (test tube, beaker, flask, graduated cylinder, pipet, buret). c. Students must know what the riser part of the lab bench is and what it is used for. Test Questions Learning Target 4: Students must employ proper laboratory techniques when working in the lab. a. Students must know what to do if a chemical gets splashed in their eye. 1 b. Students must know how to properly clean up broken glassware, dirty glassware, spilled chemicals, and spilled acids or bases. c. Students must know three ways to prevent cross contamination of chemicals. d. Students must know what to do with left over chemicals at the end of an experiment. e. Students must know which glassware can be heated with a Bunsen burner as well as the proper technique for doing so and how to safely handle hot glassware. f. Students must understand when and why glassware should be rinsed with distilled water. 26 N/A

4 LAB SAFETY RULES AND REGULATIONS Working in the chemistry laboratory is an exciting and rewarding experience. Throughout the year, you will be working with equipment and materials that can cause serious and permanent injury if they are not handled properly. However, the laboratory is a safe place to work if you are careful and knowledgeable about what you are handling. Accidents do not just happen, they are caused by carelessness, haste, and disregard for safety rules and practices. Some important safety rules to be followed in the lab are listed below. Before beginning any lab work, you must read these rules, learn them, and agree to follow them carefully every time you are in the lab. General Safety Rules 1. Safety glasses are to be worn every time there is heat, glassware or chemicals being used in the room. Safety glasses MUST be worn at all times in the lab including during cleanup and washing of glassware. 2. Students are not allowed in the chemical prep room at any time. 3. Students are not allowed to remove chemicals or equipment from the lab. 4. Always read the experiment and complete the pre-lab activities before starting work in the lab. Being familiar with the lab procedures and important safety issues associated with the lab will allow you to work more safely. 5. Perform only those lab activities assigned by your teacher. Never do anything in the lab that is not called for in the lab procedure or by your teacher. Follow all instructions, both written and verbal, carefully. 6. Work areas should be kept clean at all times. Only lab manuals and notebooks should be brought to the work area. Other books, purses, backpacks, etc. should be left at your desk or placed in a designated storage area. 7. Clothing should be appropriate for working in the lab. Jackets, ties, and other loose garments should be removed. Open shoes should not be worn. 8. Long hair and loose sleeves should be tied back or secured with a rubber band. 9. Jewelry that might present a safety hazard, such as dangling necklaces, chains, medallions, ear rings or bracelets should not be worn in the lab. 10. Do not engage in any horseplay in the lab. 11. Lab aprons are optional but recommended if your legs are exposed. 4

5 12. Set up every apparatus as described in the lab manual or by your teacher. Never use makeshift arrangements. 13. Always use the prescribed instrument (tongs, test tube holder, forceps, etc.) for handling apparatus or equipment. 14. Keep all combustible materials away from open flames. 15. Never touch, taste, or directly smell any substance in the lab unless specifically instructed to do so by your teacher. Use a wafting motion to direct the odors to your nose if necessary. 16. Never put your face near the mouth of a container that is holding chemicals. Never look directly into a test tube within which a reaction is occurring. 17. Any activity involving poisonous vapors should be conducted in the fume hood. 18. Dispose of waste materials as instructed by your teacher. Soluble substances go down the sink. Insoluble substances go in the trash. Broken glass goes in the broken glass box. Any exceptions to the above will be written in the lab. 19. Clean up all spills immediately. Use sodium bicarbonate to neutralize acid or base spills before cleaning them up with water and paper towels. 20. Keep your work area clean, and help keep the common areas of the laboratory clean. If you spill something in a common area, remember that this substance may injure someone else. Clean and wipe dry all work surfaces at the end of class. Wash your hands thoroughly after every lab. 21. Know the location of personal safety equipment (eyewash, fire extinguisher, safety shower, fire blanket, fume hood, first aid kit, glass disposal box, etc.) and how to use each one. 22. Report all accidents, spills, and broken equipment to the teacher immediately. 23. Never leave Bunsen burners unattended when lit. 24. Never heat solutions to dryness unless this is done in an evaporating dish, on a hotplate or over a boiling water bath. 25. Never heat a closed system such as a stoppered flask. 26. Never smoke, chew gum, eat, or drink in the laboratory, since you may inadvertently ingest some chemical substance. 5

6 Rules Concerning the Safe Handling of Chemicals 27. Always use a weighing boat when weighing chemicals. Never put chemicals directly on the pan of the electronic balance. 28. Read and double check labels on reagent bottles before removing any reagent. 29. Take only as much reagent as you need. 30. Always use the smallest amount of substance required for an experiment, more is never better in chemistry. Never return unused portions of a reagent to their original bottle...this may contaminate the stock solution. 31. When transferring chemical reagents from one container to another, hold the containers out away from your body. 32. When diluting a concentrated acid: Always add the acid to the water. If water is added to a concentrated acid, it may heat up enough to cause the chemicals to splash on you. Remember the saying, Do as you oughta, add the acid to the water! 33. Avoid touching chemicals with your hands. If chemicals do come in contact with your hands, wash them immediately with soap and water. 34. Notify your teacher if you have any medical problems that might relate to lab work, such as allergies or asthma. 35. If you wear contact lenses, notify the teacher. 36. Use a clean spatula when dispensing each chemical. Do not use the same spatula to dispense different chemicals because this will cross-contaminate the stock solution. 37. When making measurements, the last digit you record should be estimated one decimal place past the scale indicated on the instrument. 38. Put lids back on the container immediately after usage. Some chemicals gain or lose moisture from or to the air resulting in a change in their reactivity. 39. If you need to set the lid of a container down while you are retrieving its contents, set the lid face up to prevent contamination. If you can hold the lid during this process, do so. 40. Never place anything that is hot on an electronic balance. Heated glassware must cool for at least 10 minutes before placing on an electronic balance. 6

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8 Introduction You can t have a college preparatory chemistry course without doing experiments in the chemistry laboratory. You just can't do it! You wouldn't expect someone to be able to drive a car very well just by telling them how it's done. They need to actually practice driving the car, right? Learning chemistry is the same way. We don't expect students to learn chemistry without actually doing chemistry. Even though chemicals can be dangerous, working in the chemistry lab can be quite safe if you are careful, knowledgeable and follow all the safety rules and procedures you have been taught. This guide covers some basic safety information and use of lab safety equipment, but it is not meant to be a complete guide to lab safety. There is no substitute for common sense, so if you re not sure about something in the lab, ask your instructor. Consequences for Lab Safety Violations Failure to follow safe lab practices will result in the issuing of a written lab safety violation. Upon receiving a second violation, a parent conference will be required. For the third safety violation and every subsequent violation, you will be removed from the laboratory for that day, and you will receive an office referral. Chemical Splash Protection It is a federal law that you cannot be in a chemistry lab, work with chemicals, or be near anyone working with chemicals unless you are wearing safety glasses that comply with OSHA ANSI regulation Z87.1. We will supply you with OSHA approved safety glasses free of charge. However, you'll be required to sign an agreement stating that you will wear your safety glasses at all times while you are in the chemistry lab and every time heat, glassware, or chemicals are present in the room. You must wear safety glasses even when you're just cleaning glassware, because when your hands are slippery from soap it is even more likely that glass breakage may occur. safety glasses In the unlikely event that a chemical or solid material gets splashed into your eye, you will need to use the emergency eye wash. To use the eyewash, remove your safety glasses (and contact lenses if you wear them), pull the panic lever toward you and flush your eyes continuously for 15 minutes. It is alright if your eyelids are closed, but try to blink and move your eyes during the flushing to enhance the process. It is absolutely critical that you get contact lenses removed because they can trap chemicals against your eye and prevent the water emergency eye from flushing the chemicals away from your eye. wash station You will encounter many substances in the chemistry lab that are classified as acids, bases, solvents, oxidizing agents, or reducing agents. These substances are particularly dangerous because they are corrosive. Corrosive materials will react with living tissue (your skin) to cause 8

9 cell death more commonly referred to as a "chemical burn". Once this process has started, it is difficult or impossible to stop by rinsing with water. That is why it is so important to wash your hands thoroughly with soap and water after every lab. If a chemical is spilled on your skin, stop whatever you are doing and wash the area immediately with soap and water. If you act quickly, you can usually wash the chemical off the surface of your skin before it has time to penetrate deeper layers of skin. If a chemical gets in your mouth, spit it out immediately and rinse your mouth with water. Note the name of the chemical and notify your instructor so they can contact the school nurse immediately. If you somehow swallow a chemical, note the name of the chemical and notify the nurse immediately. If necessary, the nurse will contact the Poison Control Center, a hospital emergency room, or a physician for instructions. Being careful, working slowly, and holding bottles of corrosive materials with a paper towel wrapped around them are all good techniques for preventing chemical spills and burns. Be sure to report all chemical spills to your instructor immediately, and don't forget about the safety shower for extreme cases of chemical spills on skin or clothing. The lab safety shower is to be used only in the event of large scale chemical spills that occur on a person or a person s clothing. To use the safety shower, simply pull the triangle shaped lever downward. The shower has no off setting so it will continue to run generally delivering about gallons of water. In the event of a major chemical spill, persons using the safety shower should also remove contaminated clothing immediately as they are being flooded with water. Removing clothing will help get the chemicals away from the skin and allow the water to rinse more thoroughly. It may be temporarily embarrassing to remove clothing, but it is much better than suffering permanent scarring from a chemical burn. safety shower Simply being aware of the substances around you and moving carefully can prevent most chemical spills and splashes from ever happening. It is also good practice to tie back loose sleeves and long hair with rubber bands, remove any hanging jewelry, and wear a rubber protective apron over your clothing when handling corrosive chemicals. apron 9

10 Fire Protection There is a very real danger of fire in chemistry laboratories. There are often many flammable substances (solids, liquids, and gases) and open flame burners present in the lab at the same time. This is alright as long as you pay careful attention to the substances around you and keep flammable substances away from open flames. Always check the area around you before lighting a gas burner. Never light or use a burner around flammable liquids. You can always tell a flammable substance by reading its label. Also be aware that many alcohols, acids, and organic substances are volatile. This means the liquids readily turn into gases. These substances put off invisible vapors that are also very flammable. In addition, the burner itself uses flammable methane gas. If you are not able to light your burner within 15 seconds of turning on the gas, turn off the gas and wait 1 minute for the methane to dissipate before continuing to attempt to light the burner. In the unlikely event that a material or chemical fire occurs, the lab is equipped with class ABC fire extinguishers. This means the red fire extinguisher mounted on the wall can be used to put out : Class A Fires : ordinary materials like burning paper, lumber, cardboard, plastics, etc. Class B fires: flammable or combustible liquids such as gasoline, kerosene, and common organic solvents used in the laboratory Class C fires: energized electrical equipment such as appliances, power tools, hot plates, balances and stirrers. Water is a particularly dangerous extinguishing medium for class C fires because of the risk of electrical shock. To use the fire extinguisher, remember the P.A.S.S. method: Pull the safety pin (kind of like a grenade type pin) Aim at the base of the fire Squeeze the trigger to dispense the fire suppressing material Sweep with a side to side motion using short blasts of the trigger 10

11 There is only about 15 seconds worth of charge in a fire extinguisher so good technique is critical. Always stay between the fire and the exit never let the fire get between you and the exit. Remember to yell for help, and if you're not comfortable fighting the fire, don t.just leave and call for help. The fire blanket is located in the red cylindrical canister mounted on the wall in the lab. All fires must have oxygen to burn, so the fire blanket works by smothering flames and thus cutting off their supply of oxygen. The fire blanket is typically used to suppress fires on a person s clothing or hair. You should never use a fire extinguisher to extinguish flames on a person. If it is safe to do so, a fire blanket could also be used to cover a larger chemical or material fire as you are evacuating the room. This could be done instead of or in conjunction with the use of a fire extinguisher. As shown in the diagram, extinguishing a person with a fire blanket requires the help of others so be prepared to act quickly! Toxic Fume Protection The chemistry lab is full of volatile substances (substances that readily change phase from liquid to gas). Many toxic vapors are invisible, and some have a distinct odor, while others may be odorless. We really don't want to breathe in any vapors so we always keep volatile substances in the fume hood. Fume hoods are enclosed structures connected to a fan that pulls vapors away from us and vents them outside of the building. We can open the glass front of the fume hood to work with the chemicals without being exposed to possible harmful vapors. Very seldom, it is necessary to smell a substance (usually for identification purposes). The proper way to do this is by gently waving your hand above the container to "waft" or "direct" a small portion of the vapor to your nose. Be careful to keep your face and eyes away from the container opening, and maintain a reasonable distance (about 18 inches) from the substance at all times. The idea with "wafting" is to only direct a very small amount of vapor to the nose. If smoke or chemical fumes are present in the laboratory, all persons even those who do not feel ill should leave the laboratory immediately. Make certain that all doors to the laboratory are closed after the last person has left. 11

12 Cut and Burn Protection Minor cuts and burns are the most common types of injuries suffered in lab. The school nurse is responsible for treating injuries, however, for some types of injuries, you must take action immediately, before the nurse takes over. The following information will be helpful to you if an accident occurs. Using common sense is the best protection against these types of injuries. One way cuts can occur is by cleaning up broken glassware. If you break glassware, tell your teacher immediately. Do not clean it up yourself! If the glassware contains corrosive chemicals, you should contain the spill with kitty litter and sand or by using paper towels. Your teacher will use special gloves, brushes, and a dustpan to clean up the broken glass for you. If your teacher allows you to help, remember, NEVER place broken glass in the trash can! Broken glass must always be deposited in the broken glass disposal box. This way, the person cleaning the lab will know to be extra careful with the box, but they won't have to worry about what is in the trash can. The first aid kit in the lab is stocked with medical supplies for treating minor injuries such as small cuts and burns. Should you get cut in chemistry lab, report it to your teacher no matter how small or insignificant you think the cut is. Most cuts happen on the hands in chemistry lab. For minor cuts, rinse the wound with cold water then apply pressure with a sterile gauze. You will be sent to the school nurse who can clean the wound properly, apply an antibiotic ointment and perhaps a band-aid. For more serious cuts try not to panic (it only increases the bloodflow). Apply pressure to the wound with a sterile gauze and elevate your hand while someone summons the school nurse. In all cases, be sure to report the injury to the teacher immediately! Burns occur in the chemistry lab because hot glass looks just like cool glass. Students often fail to realize how hot glassware can get when heating it with a burner or hotplate. Usually it will take about 10 minutes for heated glassware to be cool enough to touch. Be patient...we design the experiments to allow time for proper cooling. If you encounter a burn, immediately hold the burned area under cold water and report it to your teacher. Minor burns can be treated with aloe or burn cream that is kept in the lab. This will help take the "sting" out of minor burns. Severe burns resulting in blistering or peeling of the skin need to be treated by the school nurse immediately. People who are suffering from any severe injury (for example, a bad burn or major loss of blood) may be in a state of shock. A person in shock is usually pale and faint. The person may be sweating with cold, moist skin and a weak, rapid pulse. Shock is a serious medical condition. Do not allow a person in shock to walk anywhere even to the nurse s office. While emergency help is being summoned, place the victim face up in a horizontal position, with the feet raised about 30 centimeters. Loosen any tightly fitting clothing and keep him or her warm. 12

13 NAME HOUR Lab Safety Scavenger Hunt Directions: With your lab partner, go on a scavenger hunt in the laboratory to locate all of the safety items listed in the table below. Write their locations in the appropriate column in the table and describe how and when to use each piece of equipment. Equipment Name Location in the Laboratory How and when is this Equipment Used? Fire Extinguisher Laboratory Apron Safety Shower Broken Glass Disposal Fire Blanket Eye Wash Sodium Bicarbonate (NaHCO 3 ) Fume Hood Safety Glasses Brush and Dustpan First Aid Kit 13

14 Lab Safety Symbols Directions: Match each safety symbol on the right with its meaning. Write the letter on the line. 1. Use fume hood 2. Possible violent explosion 3. Protect your eyes at all times 4. Avoid contact: corrosive material 5. Avoid contact: poisonous material 6. Special disposal instructions 7. Hot object: use tongs 8. Protect your clothing 9. Possible electrical hazard 10. Wash your hands after the lab 11. Danger: radioactive material 12. Protect your hands 13. Protect hair and clothing from open flame 14. Handle with care; guard against glass breakage 14

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16 Glassware you MUST know by name test tube skinny tube with no scale lines on it; used for doing chemical reactions beaker wide like a cup or mug; used for quick transfer of liquid; not very accurate flask cone shape; narrow mouth makes it good for swirling to mix solutions; not very accurate graduated cylinder skinny tube with a pretty accurate scale on it; used to measure liquid volume pipet pie-pet Skinny tube with an accurate scale on it; used to accurately transfer volumes of liquids Buret byur-ett Long, skinny tube with a very accurate scale; has valve at bottom to control dispensing of liquids 16

17 HOW TO USE THE BALANCE, HOTPLATE, and BUNSEN BURNER How to use the electronic balance: 1. Make sure it is plugged in. 2. Turn it on. Wait until screen reads, 0.00 g. 3. Press zero or tare button to reset to 0.00 g if needed. 4. Raise dust cover and place sample to be massed on the balance. Do NOT place chemicals directly on balance (place them in a plastic weigh boat or glassware). 5. Stand still around the balance. Sudden movements cause air movement around the balance that will cause the reading to fluctuate. How to use the hot plate: 1. Make sure it is plugged in. 2. Turn dial to set temperature. Monitor the temperature with a thermometer but don t let it rest on the bottom of the glassware. 3. Place Pyrex glassware containing the liquid to be heated on the white surface. 4. Do NOT touch the white surface, it is HOT! 5. Only use Pyrex brand glassware on the hot plate. Other types of glassware are not made to withstand high temperatures. 17

18 The Bunsen Burner hottest part of flame is the tip of inner cone-shaped flame barrel turn this counterclockwise to raise it and open air inlet for a nice, hot, roaring blue flame; turn this clockwise to lower and close air inlet to make it easier to light at first air inlet allows air from the room to enter burner to enhance combustion gas inlet needle valve adjusts gas flow into burner and therefore changes height of flame How to Light a Bunsen Burner 1. Put on safety glasses, make sure burner is level and stable on the lab bench and that there are no flammable liquids or materials anywhere near you. 2. Connect the hose from the Bunsen burner to the gas jet on the lab bench. (The gas jet is the connection on the lab bench where gas comes out. We use natural gas as our fuel here.) 3. Rotate the barrel clockwise to close air inlet valve on burner (this makes it easier to light). 4. Turn the lever at the gas jet to the on position. If you do not hear gas coming through the burner, adjust the needle valve to allow more gas to flow through burner. 5. Use the striker over the top of burner to generate sparks that will light the burner. 6. Once lit, turn barrel counterclockwise to open air inlet and adjust until you see and hear a blue, roaring flame. Use needle valve to adjust the height of the flame. 18

19 Proper Lab Safety Techniques What to do if chemicals get splashed in your eyes 1. Stop working immediately, inform the teacher and use the eyewash. 2. Your lab partner will help you get to the eyewash and turn it on. 3. At the eyewash, remove glasses and contact lenses, put face near eyewash, pull lever back toward you, allow water to flush your eyes for 15 minutes. 4. Seek immediate medical assistance. What to do if you break a piece of glassware: 1. Inform your teacher immediately, and they will help you clean it up properly and safely. 2. Do not let anyone enter the area, especially if chemicals and pieces of glass are on the floor. 3. Do not touch broken glass pieces with bare hands. Your teacher will use a brush and dustpan to collect the pieces. 4. Always place broken glass in the broken glass disposal box. Never place broken glass in the trash. 5. Inspect the counter and floor to make sure all glass pieces are found and disposed of properly. 6. Clean up spilled chemicals. See instructions for that process. 7. If glassware is broken in the sink, turn off the water and block the drain to prevent pieces of glass from becoming lodged in the drain. What to do if you spill a chemical 1. Stop working immediately, inform the teacher and a. use the eyewash if chemicals splashed in your eyes b. wash with soap and water if chemicals splashed on your skin c. use safety shower and remove clothing if you are covered with a large spill of a very corrosive chemical 2. Secure the area so others are aware of the spill. 3. Prevent the spread of the chemical by making a dam around it with paper towels or absorbant material like vermiculite, sand or cloth towels. 4. Because each chemical has different safety precautions, your teacher will instruct you on how to clean up the spill. Acids and bases must first be neutralized by adding sodium bicarbonate before wiping them up. 5. If a spill is accompanied by broken glass, remove the broken glass before cleaning the spill. 6. Always be conscious of touching the towels/cloths while cleaning and how they are disposed of afterward. Remember, chemicals can still be hazardous even on a paper towel or cloth. 19

20 How to prevent cross-contamination of chemicals: 1. Never return excess or "left over" chemicals to the stock container. A stock container is the original, labeled container used by the manufacturer of the chemical. 2. Never use the same spatula, weigh boat, pipet, etc. to dispense different chemicals. 3. Put lids on containers immediately after each use. If you must set the lid down, place it "face up" on the counter. 4. Always read the container label to make sure you know what chemical it contains. (For example, 3M hydrochloric acid and 6M hydrochloric acid are NOT the same thing.) How to properly heat and cool glassware 1. Always wear your safety glasses when using and heating glassware. 2. When using Bunsen burners and hotplates, only heat test tubes, beakers and flasks. Even these must be labeled as Pyrex glassware. Other types of glassware may break under high temperatures. 3. Never heat a closed system (a container with a lid on it). It can build up pressure and result in an explosion. 4. Never heat glassware that is chipped or cracked. 5. Always heat and cool slowly and steadily to prevent breakage. 6. Never use water to cool hot glassware. Cooling too quickly will cause breakage. 7. Always handle hot glassware with the appropriate equipment. Use heat resistant gloves, test tube clamps, tongs, etc. where applicable. Remember: hot glassware looks just like cold glassware so be careful. If you re not sure if glassware is hot, carefully place the back of your hand near the glassware to see if you sense any heat coming off it. 8. Never place hot glassware on an electronic balance because it will damage it. You must allow heated glassware to cool for 10 minutes before attempting to measure its mass. How to properly clean glassware 1. Always wear your safety glasses when handling and cleaning glassware. 2. Use soap and water to wash glassware as soon as possible after each use. 3. Use distilled water sparingly for your final rinse. Just use a little to coat the inside of the glassware (do not fill it completely up with distilled water). Distilled water will remove any unwanted contaminants from the tap (faucet) water used during washing. 4. Allow glassware to air dry on racks or lab bench. Do not place glassware near edge of lab bench where it can easily be knocked off. What is the riser part of the lab bench? 1. The riser is the raised part in the middle of the lab countertop. 2. Chemicals that are to be shared among all four groups at that bench are placed there during labs. 3. Never lend or borrow shared chemicals from other risers. riser 20

21 Make Lab Safety a Priority The chemistry lab is a safe place to work when everyone is cautious, alert, and focused on the tasks at hand. Constant attention is required when working in the laboratory. Everyone must make a conscious effort to be aware of their surroundings and the materials that are present in the lab. While most accidents can be avoided by careful planning and preparation, knowing the rules of the lab, the location and proper use of personal safety equipment, and the proper use of lab equipment and techniques will help ensure a safe and positive work environment for everyone in the lab. 21