Excerpts from the curriculum guide

Introduction

The Science Safety Manual for grades 6-12 is intended to be a general guideline for science teachers. The purpose is to minimize accidents and hazards while maximizing safety in the science laboratory and classroom situations. Although Shelby County Schools strives to stay abreast of current safety procedures, it is virtually impossible to anticipate every possible occurrence that may arise in the laboratory or classroom venue. In this document a genuine attempt has been made to cover all major problems that a science teachers might encounter.

Shelby County Schools’ science teachers must read and follow the procedures outlined in this manual, not only for the students’ well being, but for personal safety as well. Careful attention must be given to the chemical management section and other guidelines stipulated by this manual. All teachers are encouraged to remain current on safety developments.

Legal Considerations

One of the most satisfying endeavors that a student can experience occurs when the student is involved in a hands-on or laboratory exercise. While the benefits are prodigious, there are perils. It should be the desire of every teacher to minimize the risks that exist in the science laboratory. The intent of this section is not to itemize every conceivable action that can lead to an injury; rather it is intended to give the teacher an overall understanding of the process that can cause a teacher to end up in court.

Most civil court cases for damages, called torts, require that a teacher be negligent. To be sued, there must be an injury and the teacher must be responsible for the injury through acts of negligence. Negligence is the failure to exercise due cares and could include acts of omission or acts of commission. Acts of omission occur when there is failure to do what would be expected of a reasonable and prudent person. Acts of commission transpire when there is action that a reasonable and prudent person would not be expected to do. Because of the level of expertise that science teachers possess, the standards are higher than for other teachers.

The science teacher, to avoid negligence, must do the following:

Accidents do happen, but if the teacher has followed the recommendations listed above, rarely are suits filed, and if they were, the evidence would refute the charge.

General Laboratory Safety Rules
For Students

Personal Protection

The human eye is most vulnerable to injury. The Tennessee Code Annotated in Section 49-50-501 states:

Prescription glasses are not acceptable as eye protection. Splash-proof safety goggles must be worn over the prescription glasses. It is recommended that contact lenses not be worn in the lab. Prescription glasses should be substituted for the contact lenses or the lenses removed for the duration of the laboratory experiment. For any student for whom there is no possible alternative for contact lenses, the teacher should make written note of this. Those students and parents should be instructed that special problems may result in coping with an eye injury should an accident occur.

If safety glasses must be shared, then careful cleaning and disinfecting should be done. Ultraviolet disinfecting equipment should be utilized or the glasses should be thoroughly cleaned with a suitable detergent and then treated with a disinfecting solution.

Gifts

Occasionally, schools are given materials and supplies to supplement the science laboratory. While this is most often a generous outpouring of affection for the school, it may not be. All gifts must be cleared with the Central Office before acceptance can be made. The materials must always be evaluated for legal and safety reasons because of liability.

First Aid

On occasion, an accident occurs. It is important that everyone knows what to do in the event there is a mishap. A list is provided with appropriate responses for incidents that take place while the students are under the teacher’s jurisdiction. This is by no means a comprehensive list of all possible occurrences; rather, this list is meant to be a point of reference. You should identify the individual in your school that can facilitate CPR and other first aid in case of extreme emergency. Every lab must have fire extinguishers, eyewash, first aid kits and fire blanket readily available. Another point of safety is to have the MSDS sheets posted, and if plants are used, the local poison center number accessible. Make sure an accident report is completed on each occurrence.

In case of severe injury, contact the principal, nurse, or designated first aid personnel IMMEDIATELY!! They are the school’s designees to call 911.

MSDS Information

OSHA, state regulations, and Right to Know laws require that Material Safety Data Sheets (MSDS) for all chemicals present in the building be located in a central location in the building and be available to all employees at all times. Every manufacturer and supplier is required to send a MSDS sheet along with a purchased chemical. An updated, alphabetical list of the MSDS sheet must be maintained.

These MSDS sheets provide a wealth of crucial information on each chemical. The following detailed information is usually provided.

These informational sheets are one of the best guides to use to get safety information on any chemical. The Merck Index and the Flinn catalog are additional useful information sources.

Hazard Labels and Symbols

The standard warning symbol, 704M, that is explained in the NFPA book Fire Protection Guide on Hazardous Materials should be in place on all stored chemicals. A generic 704M label is illustrated as follows.

Please note that the numeral ratings are 0, 1, 2, 3, and 4, with the 0 representing no significant hazard and the 4 representing the most serious hazard. The bigger the number, the bigger the hazard. In addition the color-coding differentiates the type of hazard. The blue background represents health hazard, the red represents flammability, the yellow represents stability, and white gives any special precautions.

Safety Equipment

Standard laboratory equipment is used to make the laboratory a safer place. In order to make sure this is achieved, this equipment should be properly used and maintained.

FIRE EXTINGUISHERS
All labs should have Tri-Class (A,B,C) fire extinguishers located near an exit, not a dead end route. At least one large back up extinguisher of dry-chemical powder type should be located outside each lab. Every student and teacher should be aware of the location of the fire extinguishers and trained in the proper manner of operating them.

FIRST AID KITS
First aid equipment should be available in each lab. If a severe injury occurs someone knowledgeable about the accident should accompany the injured person to the medical facility. The location and phone numbers of the local physicians qualified to handle chemical emergency cases and local medical facilities should be posted in the laboratory.

EYE WASH
Eyewashes should be checked and flushed once a month. The eyewash should deliver a gentle flow of tempered, clean, aerated water for an extended period of time, at least 15 minutes. The eye wash should be located near the safety shower if possible so the eyes can be washed while the rest of the body is showered if necessary. All students should know the location and the proper method for using eyewash.

SAFETY SHOWER
Safety showers should have valve handles instead of pull chains, which are difficult to grasp in an emergency. The valve should open readily in either direction and remain open until turned off. Water must flow sufficiently to drench the person rapidly and to accommodate more than one person. All students should know the location and proper method of using the safety shower. The shower should be flushed once a month.

FUME HOOD
Fume hoods serve to exhaust toxic, offensive or flammable vapors from the laboratory. The hood is not a means for disposing chemicals. Periodically use a velocity meter of a smoke generator to check the airflow in the hood (70-100 linear feet per minutes). When working with materials in the hood, work as far under the hood as is practical and comfortable (six inches inside the hood area is a minimum). When possible avoid working with the hood sash completely open.

MASTER SHUT-OFF VALVES AND SWITCHES
Master shut-off valves and switches for gas, water and electricity should be located where they are accessible to teachers in the event of an emergency. The valves should be shut off when the lab is not in use. No keys should be left in the shut-off valves.

ELECTRICAL OUTLETS
All electrical outlets must have a grounding connection requiring a three-prong plug (OSHA regulation). Ground-fault interrupters must protect all electrical outlets. Eliminate all wiring that is frayed or worn, or stretched across the floor where someone could trip over it. Eliminate unlabeled panel boards; electrical outlets with missing cover plates and excessive use of extension cords. The condition of wiring, plugs, cords, and related equipment should be frequently checked. All personnel should know the location of circuit breakers and how to cut off all electrical service in case of fire or accident. All circuit beakers should be labeled.

FLAMMABLES CABINETS AND SAFETY CANS
Fire-hazard chemicals in quantities greater than 500 mL should be kept in metal safety cans if flammable containers are not available. The cabinet should be well ventilated and locked at all times. Do not overload flammables cabinets or safety cans (limits on quantities depend upon the cabinet and the safety can).

FIRE BLANKETS
A fire blanket should be placed in each lab. Regularly inspect fire blanket for rips and holes. Students should know the location and proper method for using the fire blanket.

EMERGENCY EXIT LIGHTS
All labs should have emergency exit lights, which are activated by power failures. The custodial staff should check the lights several times during the school year.

ACID CABINETS
Acids should be stored in an acid cabinet made of wood. If an acid cabinet, is not available then acids should be stored in safety cubes. Acid cabinets should be checked monthly for excessive odors. A charcoal filter can be used to absorb odors. The acid cabinets should be inside the chemical stockroom.

SPILL KITS
All labs should have equipment used in cleaning up spills. Spill kits can be obtained from various chemical companies. If a spill kit is not available, a 10% soda ash-sand mixture, vermiculite or cat litter can be used. However, always check MSDS sheets for specific methods for handling spills.

Basic Laboratory Procedures

INSERTING GLASS TUBING INTO A RUBBER STOPPER
Be sure that all ends are fire polished. Lubricate the glass and the rubber stopper with glycerol or water. Never force tubing into a stopper. Protect your hands with leather gloves or a cloth. Hold both hands as close together as possible. Ease the glass in with a gentle twisting motion. If the insertion is difficult, discard and start over with a stopper with a larger hole.

USING THERMOMETERS
Mercury thermometers present an ongoing and serious hazard; they are not permitted. Use spirit filled thermometers or substitute metal, digital, or electronic temperature probes. If a spirit filled thermometer is used, have an anti-roll device in place. Securely clamp the thermometer in place when in use. Do not use the thermometer as a stirring device.

USING A GAS BURNER
Always hold your face and body away from the burner. Be certain that the rubber hose is securely attached to the gas and the burner. Light the match first. Hold the match up to the oxidizing zone on the flame and slowly turn on the gas. Adjust the air to get a blue flame and adjust the gas flow to get the desired flame. Do not leave a lit burner unattended.

GLASS BEAKERS, TEST TUBES AND TUBING
The most common accidents in the laboratory involve small cuts and burns from the glassware used. Remember that hot glass looks exactly like cold glass. Place all hot glass on a hot-pad or heat resistant surface and allow plenty of time for it to cool. Use the proper tongs or gloves to handle hot glassware. Purchase only Pyrex or Kimax brand glassware for beakers and test tubes. Exax brand is not heat resistant. Do not heat graduated cylinders or volumetric flasks. Do not heat reagent bottles or storage bottles. Heat only a glass container if it has sufficient liquid in it. Do not evaporate to dryness or heat an empty glass container. Use boiling chips to break up the bumping action during heating of liquids. When heating substances in test tubes be absolutely positive that the mouth of the test tube is pointing away from any and all individuals. Discard promptly any broken, cracked or starred glassware.

BALANCES
Balances are one of the most expensive items used in the laboratory. Any spilled material must be cleaned up and dried off immediately. Materials to be massed must always be placed in a container. Only objects may be massed directly on a balance pan; any substance, chemical or material must be placed in an appropriate container, which may be a weighing paper, a weighing dish or a beaker.

Demonstrations

Safety Contract

Click here for separate file to print out safety contract
or
Click here to download a PDF file of the safety contract

THE PURPOSE OF THIS CONTRACT IS TO MAKE EACH STUDENT AWARE OF HIS/HER OWN RESPONSIBILITY FOR SAFETY IN THE SCIENCE LABORATORY.
I WILL:

Note: Students must realize the implications of improper behavior. Misbehavior will require the immediate removal of any student from the laboratory experience.

I, ______________________________, have read and agree to follow the
safety regulations set forth above as well as other safety regulations given to me by my teacher. I will follow all oral and written instructions provided by the teacher and/or school administration.

Student’s Signature: ________________________ Date: _______________

Parent’s Signature: _________________________ Date: _______________