LABORATORY SAFETY

Proper Laboratory Attire

You must wear safety goggles in the laboratory, even if you wear regular glasses. Safety goggles provide much more protection than prescription glasses do because they form a tight seal around the entire eye area. Wear your safety goggles whenever you are in the laboratory whether you are working or not. Why? Other students around you who are still working might have an accident which could reach your work area or you might have an accident yourself while you are cleaning up. Recently, a student who was cleaning up after an experiment removed her goggles only to splash ammonia in her eyes a few minutes later while she was washing a flask. Fortunately, she got to the eyewash quickly, and her eyes suffered only minor irritation. But there are many other chemicals which can cause permanent damage to the eyes in less time than it would take you to reach the lab eyewash.

Contact lens wearers take note: Chemical splashes or fumes reaching the lens may attack it and/or diffuse beneath the lens and injure the eye. Thus, contact lenses may be worn in the laboratory only if you also wear safety goggles and if you handle any fuming chemicals in a fume hood.

Wear old clothing to cover as much of your skin as possible. No open-toed shoes or sandals, halter tops, gym shorts, etc. Accidents which can ruin clothing and injure bare skin do occasionally occur. While lab aprons are available in lab, they do not protect arms, legs, and feet. If you arrive to lab wearing open-toed shoes or sandals, you will be given disposable plastic boots to wear over them.

Wear disposable gloves when required. Occasionally, we work with substances which are toxic or whose toxicity is unknown. For these experiments, the lab manual will direct you to wear disposable gloves. (You are welcome to wear gloves during any of the other experiments we perform, too.) Gloves are located in a cabinet next to the windows in the laboratory.

Safety During Lab

In case of accident or fire, however minor, notify your laboratory instructor immediately.

No student may work in the laboratory at any time unless an instructor is present. Under no conditions are unauthorized experiments to be performed.

Never smoke, eat, or drink in the laboratory.

Never leave anything unattended while it is being heated or is reacting rapidly. Turn off Bunsen burners if you must step away from your work area even for just a few seconds.

Never taste any chemicals in the laboratory. Be very cautious when testing for odors.

Use hoods whenever any fumes are involved. Ordinarily, the lab manual will make it clear when the hood is to be used. If in doubt, ask your instructor.

Dispose of chemicals in the proper manner. Never return unused reagents to stock bottles. Throw solid wastes into waste jars and liquid wastes into recovery bottles as directed. Flush chemicals which are not to be recovered down the sink with a large excess of water. If you do not know how to safely dispose of a certain chemical, ask your instructor.

If chemicals are spilled on desktops or the floor, they should be promptly cleaned up. Ask your instructor for the best cleanup technique for the particular chemical involved.

All broken glassware should be placed in the glass waste box under the reagent table, not in the regular trash. All thermometers used in general chemistry are spirit thermometers (containing no mercury), so broken thermometers may be placed in the glass waste box as well.

Never point a test tube filled with boiling liquid at your neighbor. Liquids at, or near, the boiling point frequently bump, causing the hot liquid to shoot rapidly from the tube.

Always add acids to water, never water to acids. Certain acids generate so much heat upon dilution that when you add even a small amount of water to the acid, the acid boils and spatters! This can be prevented by adding the (small volume of) acid to the (relatively large volume of) water. The water will act as a "heat sink."

Safety Equipment

Below is a map of the general chemistry laboratory. On the first day of lab, take a minute to locate the fire extinguisher nearest your work area as well as the safety shower and the eyewash. Mark the locations on the map. Familiarize yourself with the operation of these important pieces of safety equipment. It's an especially good idea to try out the eyewash. The safety shower is used in emergencies only (clothing fires or severe chemical spills).

Preventing Cuts

Accidents involving broken glassware are common in the laboratory, but taking the following precautions will help you avoid them entirely. Never try to catch a dropped glass item. The risk of injury to your hand by any flying broken glass far outweighs the cost of the glassware. Never apply force when inserting glass tubing into objects (e.g., glass pipets into pipet pumps or glass tubing into stoppers). Very harmful injuries may result from these simple operations if the tubing snaps and is forced into the skin. Your instructor will demonstrate the proper insertion techniques which include gentle twisting of the tubing into the object. Finally, heat will shatter glassware that is not Pyrex or Kimax (heat resistant). Be sure to check for a Pyrex or Kimax symbol before using glassware for any manipulation that requires heating.