LABORATORY SAFETY

 

            Chemistry is an exciting subject!  Each laboratory experiment gives you the opportunity to confront the unknown and to gain a better understanding of how the “real” world works.  Each experiment holds many secrets waiting for you to discover.  Each lab exercise is designed to help you grasp a better understanding of the principles discussed in lecture.

            The laboratory can be, but is not necessarily a dangerous place.  Under most situations the chemistry lab is a safer place to be than the usual kitchen.  However, the sheer number of students working, and the number of lab set-ups necessitates vigilance and care at all times.  Use logical precautions, and read and understand the instructions for each lab exercise before attempting the experiment.  If at any time you have a question as to what is to be done, or how a piece of equipment or how chemicals are to be used and disposed of ASK YOUR INSTRUCTOR.  Most procedures, instructions, and precautions are just common sense practices.

 

SAFETY EQUIPMENT

 

EYE PROTECTIONS/SAFETY GLASSES:  Safety glasses or goggles MUST be worn for each lab session when ANYONE in the lab is working with chemicals or equipment.  The American Chemical Society now approves the wearing of contact lens in the lab as long as safety glasses are worn.  Safety glasses or goggles must be worn over regular prescription glasses, even if they have plastic or shatter proof lenses, because of their small size.  Sunglasses are not allowed because dark lenses limit vision in the lab.  Do not rub your eyes, nose, etc. without washing and drying your hands first.

 

EYE WASH:  The eyewash fountain in your laboratory is located next to the entrance door to the lab.  It resembles a drinking fountain, somewhat, but with two faucets directed to one another.  These flush water over both eyes when the head is held between them.  If chemicals splash your eyes, use the fountain to flush them for 15 minutes, thereby washing the chemicals out of the eyes.  Always report such an accident to your instructor.

 

SAFETY SHOWER:  The safety show is found next to the eyewash fountain.  It showers large quantities of water on an individual using it.  It may be used to put out fires or to douse a person who has suffered a large chemical splash over their body.  Never activate a safety shower except in an emergency.

 

FIRE EXTINGUISHER:  Look around the room to locate the fire extinguisher nearest you in your laboratory.  In M23 and M24 there is one located next to the balance room door.  In M26 there are three fire extinguishers.  One is on the wall between the windows and the hoods, the second is one the wall next to the bulletin board, and the third is on the side of the counter next to the eye wash fountain.  These fire extinguishers contain carbon dioxide under pressure and can be used to smother most fires.  To use it open the door of the cabinet, lift the extinguisher off the hook, pull out the safety pin from the handle, point the nozzle at the fire, and squeeze the handle.

 

FIRE BLANKET:  The fire blanket is in a long, metal box secured to the wall.  A fire blanket may be used to wrap around a victim, who has caught fire, thereby smothering the fire.  In M24 the fire blanket is on the wall next to the balance room door.  In M26 the fire blanket is on the window wall between the windows and the bulletin board.

 

FIRST-AID KIT:  For M23 and M24 there is a first-aid kit in the preparatory room between the two rooms on top of the file cabinets.  For M26 there is a first-aid kit secured to the wall in the preparatory room containing the ice machine.  Always report any injury requiring use of the first-aid kit to your instructor because follow up treatment may be necessary.

 

FUME HOODS:  Six fume hoods are located along one wall in each of the labs.  Each hood consists of a partially enclosed laboratory bench equipped with suction fans that draw fumes out of the area and expel them into the open air above the building.  Any experiments you do that produce toxic fumes should be carried out in a fume hood.  Your instructor or the experiment directions usually tell you which experiments require this, but any time an obnoxious or choking odor is produced, you need not wait to move over to the hood to do your work.  If your nose does not like the smell of your lab work, it is likely that your body will not like it either.  Always use the fume hood in such situations.

 

GLOVES:  When working with caustic chemicals, it is a good idea to wear gloves.  Gloves are provided in all the labs.  If you are in doubt, ask your instructor.

 

MISCELLANEOUS HAZARDS

FIRES:  Minor fires can be extinguished by simple means, such as simply allowing it to burn out, if not much solvent is involved, or immediately dousing with water in your lab sink.  Fire extinguishers should be used without hesitation for more serious fires.  If your clothing catches fire, the safety shower or the fire blanket should be used.  If you see another person’s clothing catch fire, immediately put him/her under the safety shower and douse him/her until the fires is completely extinguished.  Or the fire blanket can be wrapped around the victim to smother the fire.

 

CHEMICAL SPILLS: ACIDS, BASES, AND OTHER CAUSTIC CHEMICALS:

Relatively Small Amounts on person

1.       Flush exposed area immediately with tap water from sink for several minutes.

2.       See instructor for further treatment

a.       acid – use sodium bicarbonate solution (NaHCO3)

b.       base – use boric acid solution (H3BO3)

c.       bromine – use sodium thiosulfate solution (Na2S2O3)

3.       If burning sensation accompanies a spill, report it immediately to your instructor.  He/she may

a.       recommend further action

b.       send your to a doctor if it is serious

Larger Amount on person

      Immediately douse yourself under the safety shower, while removing clothing quickly to minimize the

      time the chemicals are in contact with your skin.

Chemicals on lab benches, etc.

      Small amounts can be wiped up with a paper towel.  Larger amounts may need to be neutralized before

      being removed.  See your instructor for proper removal of large amounts of chemicals.  Any spill should

      be cleaned up immediately.  Even a small amount may harm another student, who inadvertently touches

      it and then does not know how to treat the resulting chemical burn, because he/she does not know what it

      is.

 

TO PREVENT SPATTERING:

1.       When diluting concentrated acids

        always add the ACID TO WATER, never the reverse

2.       When heating in a test tube

        hold the test tube with a wire holder

        hold the test tube at an angle, (be sure it is not pointed at someone),

        heat near the surface of the liquid while gently agitating the contents.

3.       When shaking a test tube to mix its contents, do not use your finger as a stopper. 

      Use a rubber stopper.

 

HOT EQUIPMENT:  Use a wire gauze or heat resistant pad under the object.  Do not place directly on the bench.  The object may stick, become contaminated with the bench surface, or cause damage to the bench surface.

GLASSWARE:

1.       Broken glassware should be immediately cleaned up using the dustpan and brush in the tall cabinet near the entrance door.

2.       To  help prevent breaking glassware, never try to dry graduated cylinders, burets, or volumetric flasks with your burner.  They are not made of heat resistant glass as are beakers, test tubes, and Erlenmeyer flasks.

3.       To help prevent burns remember hot glass looks the same a cold glass.

 

SMELLING CHEMICALS:  If directed to detect odors in an experiment, never inhale the fumed directly.  Instead, cup your hand and gently fan the fumes toward your nose and sniff only tiny amounts.

 

FOOD AND DRINK:  Any and all foods and drinks are prohibited in a chemistry lab.  Never taste any chemical and consider all chemicals hazardous unless instructed otherwise.  Always wash your hands with soap and water before eating after working in the chemistry lab.

 

ORGANIC CHEMICALS:  Many commonly used organic compounds turn to vapor easily and also tend to burn easily or explode, if used around flames.  When organic solvents are used, we normally do not use open flames (Bunsen burners).  We use hot plates or sand baths.

Be sure you know where the fire extinguishers are located in the lab just in case.

 

HORSEPLAY:  The laboratory is no place for horseplay, because there is always a danger of breaking or spilling something.  Fooling around in the laboratory is an invitation for serious accident.

 

OOPS:  Always report ANY injury, accident, or spill to your instructor immediately!

 

HANDLING REAGENTS

1.       Never carry a reagent bottle to your desk.  (Other students can’t find it.)

Carry liquids in clean glass containers and solids in weighing boats or on weighing paper.

 

2.       Read label twice before taking any chemical.

 

3.       Take only the amount of chemical from the reagent bottles needed for an experiment.

Do not return unused chemicals to reagent bottles.  This will prevent contamination.

 

4.       Dispose of excess hazardous chemicals in designated containers.  Dispose of nonhazardous solids

in wastepaper baskets, not in the sink.  Nonhazardous liquids can go in the sink.  If in doubt, ask your instructor or stockroom personnel.

 

5.       When pouring liquids hold the palm of your hand over the label to prevent possible drops from

running down the bottle and defacing the label.  This also helps to protect you hand from chemicals on the side of the bottle.

 

6.       When obtaining chemicals, use the spatula or dropper provided and taped in a test tube to the side of

the bottle.  Be sure to replace the spatula or dropper in the holder on the bottle from which it came, so the contents is not accidentally contaminated by someone using the wrong spatula or dropper.

 

7.       Do not lay stoppers down.  This allows them to become contaminated.  Always replace caps and

stoppers to the original bottle.  Always recap tightly immediately after use, since moisture in the air can affect many of the chemicals.

 

8.       Be economical in the use of reagents, diionized water, and detergent.

 

WORKING IN THE LAB:

1.       Arrive on time. 

      Laboratory direction and procedures are given at the beginning of the laboratory period.

 

2.       READ the lab experiment procedures before coming to lab.

 

3.       An INSTRUCTOR must always be present, whenever you work in the lab.  If it is not a lab in which you are scheduled, you must get the instructor’s permission.

 

4.       Do not bring unnecessary items to the laboratory, if possible.  Do not place any personal items

      (pocketbooks, bookbags, coats, umbrellas, etc.) on the laboratory bench or at your feet.  These items

      should be placed in the cabinet under the sink or in the closet next to the door coming into the lab.

 

5.       Students who are pregnant assume all responsibility for the risk that chemicals may impose on the

      unborn child.

 

6.       Avoid wearing loose clothing and tie back long hair, as these are laboratory fire hazards.

 

7.       Wear closed shoes and garments that cover as much skin as possible, such as long sleeve shirts and

pants, for best protection.

 

8.       WORK independently, unless instructed to do otherwise.

 

9.       RECORD DATA directly into your report sheet or notebook in ink.

Do not recopy from another piece of paper.  If you make an error, neatly cross the data out with a single line, so it may still be legible, and write in the corrected data nearby.  Do not use white out.

 

10.   BALANCE:  A balance is a fragile, expensive, and accurate piece of equipment. 

      Never place chemicals directly on the balance pan.  Use a clean glass container, weighing boat, or

      weighing paper between the chemical and the balance pan.  Weigh objects at room temperature. 

      Do not weigh hot or warm objects.

 

11.   EQUIPMENT AND DRAWER:  You are responsible for keeping your equipment and drawer clean

      during the semester, as well as when your turn it in at the end of the semester.

 

CLEANLINESS:

1.       Clean off the lab bench and sink nearest you before you leave the lab.  The janitors do not clean the

lab benches or sinks, only the floors during the semester.

 

2.       Keep balances clean.  If you spill chemicals on a balance, immediately clean them off to prevent

      corrosion.

 

3.       Clean each piece of equipment as soon as you finish using it, because it is easier to clean

immediately after use.

a.       Use detergent, tap water, brush, and “elbow grease”.

b.       Rinse thoroughly with tap water, to get rid of detergent.

c.       If equipment is still dirty, get help from instructor.

d.       Rinse with diionized water from a wash bottle.

e.       Dry outside (and inside if possible).