Safety in the Chemistry Laboratory

Laboratory Safety

Safety measures in the chemistry laboratory. Handling solids and liquids. Chemical spills and clean up. Laboratory fires. Chemical burns and swallowing of chemicals. Personal injury and illness. The OSHA perspective towards lab safety.

SAFETY MANAGEMENT GUIDELINES

• Safety demands an awareness of your surroundings. Be alert to unsafe conditions or actions in the laboratory. Call attention to them and make corrections.
  
• Have an evacuation plan and be familiar with it. Keep passageways clear. Employ exits.
  
• Learn to interpret MSDS info in regard to health hazard, flammability, reactivity, storage and disposal. Check for TLV, IDLH, Flash point and Fire fighting media.
  
• Know how to use laboratory safety equipment and the exact positions of safety shower, eye wash station, respiratory gear, fume hood, fire alarm, fire extinguisher, and spill clean up materials.
  
• Be aware of ignition sources, open flames, heat and electrical equipment.

LABORATORY SAFETY PRECAUTIONS

Laboratory Clothing.
Wear shoes that fully cover the feet. Sandals and clogs are not adequate. Shoes provide a great deal of initial protection in the case of dropped containers, spilled chemicals, and unseen hazards on the floor. Use old clothes, which are not too loose, especially at the sleeves. Laboratory coats or aprons must be worn over clothes. Snaps or fasteners are preferable to buttons for quicker removal in case of an emmergency. Tie back long hair so that it will not fall into flames or chemicals.
Avoid shorts and mini skirts in the lab. Exposed body skin give added risk to irritation and burns by corrosive chemicals and gases.
Aprons
Plastic or Rubber - protects against corrosive and irritating chemicals.
Labcoats
Cotton - good against flying objects, sharp or rough edges (usually treated with a fire retardant)
Wool - protects against molten splashes, small acid spills and small flames.
Synthetic fibres - protects against IR and UV radiation but burns easily and can be ruined by strong solvents.
Safety Glasses.
Wear safety glasses at all times in the laboratory. Goggles are required to be worn at each lab period and should also be worn over prescription glasses. Contact lenses should not be used during the lab. Goggles designed for contact wearers should be made available.
Working Alone in the laboratory
All work must be performed under the supervision of a laboratory instructor/demonstrator. The instructor should be aware of the exact nature of all work being done in the laboratory.
Unauthorized Experiments.
Do only the experiment which has been assigned by the laboratory instructor. Never do any unauthorized experiment in place of the one assigned by the instructor. Do not change the designated procedure without the advice of the instructor.
Read up experiment procedure.
Know exactly what you are to do. Occasionally incomplete directions or a misunderstanding of instruction causes accidents. Whenever you are in doubt, ask your instructor.
Think about what you are doing and why you are doing it at all times.
Do not start any experiment involving the use of an experimental set-up (apparatus) until it has been checked and approved by your laboratory instructor unless otherwise instructed.
Food
Do not eat, drink or smoke in the laboratory.
For safety purposes, assume all chemicals to be poisonous either by themselves or because of impurities. Also avoid direct contact with organic chemicals. Many are absorbed directly through the skin.
Cleanliness
Keep the lab bench clean at all times.
If a solution, a solid, or liquid chemical is spilled on the bench or on the laboratory floor, clean up the spill immediately. Any chemical spilled on your skin or your clothing, should be washed immediately and thoroughly. Notify the laboratory instructor of the spill.
When leaving the laboratory, wipe the bench top thoroughly. Make sure that your work area is clean and free of spilled chemicals or scraps of paper. Wash your hands with detergent or soap and water.
Waste disposal
Dispose of waste and excess materials in the proper manner.
Used matches, paper, broken glass, or porcelain ware should be placed in the appropriate containers but not in the sinks or cup sinks. If you have any questions concerning the waste disposal, ask your instructor for the proper procedure.
Fume Hood
Use fume hood when necessary.
Use the fume hood when you are so directed by the laboratory instructor, or when it is indicated to do so on the experimental procedure. Fume hoods remove toxic vapors and irritating odors from the laboratory. The removal of these materials is essential for protecting the health and safety of those people working in the laboratory.
Burners
Light burners only when needed.Properly extinguish any flame not being used. Any open flame may ignite reagents being used by you or others near you. Many organic liquids are highly flammable and these liquids should be heated only on hot plates or heating mantles.
Reactions
Never look directly into the mouth of an open flask or test tube if it contains a reaction mixture.
Hot Objects
Avoid touching hot objects. When heating a chemical in a container, the clamp holding the container and the burner will also become hot. Place the object on a piece of asbestos board or on wire gauze, which is not directly touching the bench top. Glass objects take a long time to cool, so allow plenty of time to cool before touching them.
Glass rods
Use extreme caution when inserting glass into stoppers. Be very careful when inserting glass tubing, glass rods, thermometers, funnels, or thistle tubes into rubber stoppers or corks. Protect your hands by holding the glass and stopper with a cloth towel or multiple layers of paper towels. Always lubricate the glass surface with water or glycerol.
Glassware
Use only equipment which is in good condition. Defective equipment is an important source of accidents. Some defects to watch for include:
• chipped tips on burets, pipets, and funnels.
• chipped or broken rims on beakers, flasks, funnels, graduated cylinders and test tubes.
• cracks in beakers, flasks, graduated cylinders, test tubes and crucibles.
• star-shaped breaks in the bottom of test tubes or near the bottom edges of beakers and flasks.
• severe scratches in the bottom of beakers, flasks, and test tubes.
• sharp edges on glass tubing and glass rods.
These defects may be repaired by a glass blower or have them replaced.
Also look for
• inflexibility in rubber stoppers - (replace)
• separations in the mercury column of thermometers - (replace)
• non-working parts of screw clamps, buret clamps or rings. - (clean off corrosion, lubricate or replace)
• Replace all old and worn electrical cords.

GLOVES

Gloves should be selected on the basis of the material being handled and the particular hazard involved. Glove manufacturers and the Material Safety Data Sheets (MSDSs) accompanying products in use are good sources of specific glove selection information.

PVC protects against mild corrosives and irritants.
Latex provides light protection against irritants and limited protection against infectious agents.
Natural Rubber protects against mild corrosive material and electric shock.
Neoprene for working with solvents, oils, or mild corrosive material.
Cotton absorbs perspiration, keeps objects clean, provides some limited fire retardant properties.
Zetex® when handling small burning objects. These are a good replacement for asbestos gloves.
(Asbestos containing gloves may not be purchased or used in labs since asbestos is a known carcinogen.)
When working with extremely corrosive material, wear thick gloves. Take extra precaution in checking for holes, punctures, and tears. Care should be taken when removing gloves. Peel the glove off the hand, starting at the wrist and working toward the fingers. Keep the working surface of the glove from contacting skin during removal. Contaminated disposable gloves should be discarded in designated containers (e.g., radioactive or biohazardous waste containers).
Wash hands as soon as possible after removing protective gloves.

HANDLING LIQUID CHEMICALS.

Take an appropriate container to the reagent shelf. Avoid measuring volumes of strong acids and alkaline solutions with your graduated cylinder held at eye level. Support your graduated cylinder on your bench. Add hazardous liquids a little at a time, inspecting after each addition.
Reagent in dropper bottle.
If the general supply bottle is equipped with a dropper, use it, but be sure that the dropper never touches your container or the contents in it. Never put it down on the bench top, but return it immediately the right reagent bottle.
Reagent in a stopper bottle.
If the general supply bottle is equipped with a stopper, the stopper should either be held during the transfer or placed on its flat top. Do not lay the stopper on its side on the bench top. Pour chemicals from the general supply bottle into your container. Be sure that the proper stopper is returned to the supply bottle; do not interchange stoppers.
Mixing.
If liquid chemicals are to be mixed with water, always add the concentrated chemical to water rather than water to chemical. This keeps the new solution dilute at all times and avoids many accidents. Usually addition should be done slowly, using small quantities. It is especially important to add acid to water because of the heat generated.
Pipetting.
Liquids are drawn into the pipet by applying a slight vacuum at the top, using a small rubber suction bulb but NEVER THE MOUTH.Use pipette fillers.
Heating.
Liquids in beakers and flasks can be heated by placing them on a ring or tripod stand on wire gauze with the container preferably supported by a clamp. Liquid should never be heated in a graduated cylinder or in other columetric glassware.
Disposal.
Check with your laboratory instructor before disposing of any chemicals down the drain. If the liquid chemical can be disposed of in the sink, dispose of it by rinsing it down the sink with large quantities of water. Avoid unnecessary splashing during this process by pouring the chemical directly down the drain while the water is running vigorously.

HANDLING SOLID CHEMICALS.

Take an appropriate container to the reagent shelf where the general supply is kept. Solids are somewhat more difficult to transfer than are liquids, so a wide-mouthed container such as a beaker is preferable.
During the transfer, hold the stopper or lay it on the bench without contaminating the stopper. Solid chemicals are most easily poured by tipping the general supply bottle and slowly rotating it back and forth. Mere tipping of the bottle alone often causes large chunks to come out very suddenly which leads to spills. If you use your own spatula, be sure that it is absolutely clean. Return the proper stopper to the general supply bottle; do not interchange stoppers.
Mixing.
If the solid is to be mixed with a liquid, add the solid to the liquid. Additions should be made in small quantities except in special circumstances.
Disposal.
If the laboratory instructor directs you to dispose of any solid chemicals in the sink, flush it down the drain with copious amounts of running water. All other solids should be disposed of in special containers provided for this purpose.

CHEMICAL SPILLS IN THE LABORATORY

In all cases, immediately alert your neighbours and laboratory instructor of the spill.
Locate spill cleanup materials. Laboratories should be equipped with spill cleanup kits.
Wear the appropriate personal protective equipment (e.g., gloves, goggles) when cleaning up spills.
Non volatile and non flammable materials
If the material is not particularly volatile, nor toxic, and poses no fire hazard the liquid can be cleaned up by using an absorbent material which neutralizes them, for example, sodium bicarbonate solution or powder for acids, or sodium thiosulfate solution for bromine. Rubber or plastic gloves should be worn while using absorbent materials. A dustpan and brush should be used to remove the absorbent material. Then, the contaminated area should be cleaned with detergent and water and the area mopped dry.
Volatile, flammable and toxic spill materials
Alert everyone in the laboratory to extinguish flames, disconnect spark-producing equipment, shut down all experiments, and evacuate the laboratory. The laboratory instructor and safety personnel will handle the clean up.
Acid Spills
Apply neutralizer (or sodium bicarbonate) to perimeter of spill. Mix thoroughly until fizzing and evolution of gas ceases. NOTE: It may be necessary to add water to the mixture to complete the reaction. Neutralizer has a tendency to absorb acid before fully neutralizing it. Check mixture with pH indicator paper to assure that the acid has been neutralized.
Transfer the mixture to a plastic bag, tie shut, fill out a waste label, and place in the fume hood. Notify supervisor.
Caustic Spills
Apply neutralizer to perimeter of spill. Mix thoroughly until fizzing and evolution of gas ceases. Check mixture with pH indicator paper to assure that the material has been completely neutralized.
Transfer the mixture to a plastic bag, tie shut, fill out a waste label, and place in the fume hood. Notify supervisor.
Solvent Spills
Apply activated charcoal to the perimeter of the spill. Mix thoroughly until material is dry and no evidence of liquid solvent remains.
Transfer absorbed solvent to a plastic bag (if compatible), tie shut, fill out and attach a waste label, and place in the fume hood. Notify supervisor.
Mercury Spills
Using a mercury vacuum, vacuum all areas where mercury was spilled with particular attention to corners, cracks, depressions and creases in flooring or table tops.
To clean up small spills with a mercury spill kit, dampen the mercury sponge with water, then wipe the contaminated area. Do this procedure slowly to allow for complete absorption of all free mercury. A silvery surface will form on the sponge.
Place the contaminated sponge in its plastic bag, tie shut, fill out and attach a waste label, and place in the fume hood.

CHEMICAL SPILLS ON A PERSON.

Over the body
Within seconds, quickly remove all contaminated clothing while person is under safety shower. Flood the affected body area with cold water for at least fifteen minutes. If pain continues or resumes, flood with more water. Wash off chemicals with a mild detergent solution. Do not apply any materials such as neutralizing agents or salves, to the area. Obtain medial assistance immediately.
On small area of body
Immediately flush area thoroughly with cold water. Wash with a mild detergent solution. If there is no visible burn, wash out the area with warm water and soap.
In the eyes
You will need to assist the person who has chemicals spattered in the eyes. Immediately drench the eyes at the nearest emergency eyewash station. Force the eye or eyes open to get water into them. The speed of your response to this emergency is extremely important. Notify the laboratory instructor of the accident immediately.

SWALLOWING CHEMICALS.

The laboratory instructor should determine what specific substance is ingested.
The individual should be forced to drink copious amounts of water while en route to medical assistance. The Health Center or Hospital should be notified while the individual is in transit as to what chemicals are involved.

BURNS.

For burns by hot objects, flames or chemical, flush the affected area with cold water for several minutes. Notify the laboratory instructor of the burn and he will arrange transportation to the infirmary if necessary.

FIRE.

Give assistance to people first. If the person clothes are on fire, guide him/her without running to the fire blanked station or to the safety shower and drench him. Do not hesitate because of such insignificant things as shrinking sweater, ruined hairstyles, or soggy discomfort. While the victims are being cared for, other available people should try to shut off or reduce the fuel supply to the fire. Get a fire extinguisher and direct its spray toward the base of the fire. If the fire is too big to extinguish, have the laboratory instructor call the fire department and sound the fire alarm.When the fire is out, be sure all extinguishers used are tagged as empty and are replaced.

INJURY OR ILLNESS.

Render assistance if necessary. For minor cuts, wash them thoroughly, apply a good antiseptic, and a band-aid. For major cuts, severe bleeding or serious illness, send someone for help and administer first aid. Only a physician is trained to treat serious injury or illness. Notify the instructor immediately.