By Ken Roy
Posted on 2021-04-06
On November 13, 2020, a troubling article by the Sinclair Broadcast Group was published. It was titled “More than 160 students, teachers nationwide hurt in science experiments gone wrong.” The article mentions one critical experiment/demonstration known as The Rainbow Experiment that is designed to show how burning different salts results in different characteristic colors. The article notes how dozens of students nationwide have actually seen flame jetting in action, with tragic consequences. The Rainbow Experiment usually incorporates the use of methanol (a.k.a. methyl alcohol). Numerous students and teachers over the past several decades have been seriously injured as a result of doing this demonstration/lab activity in school science laboratories.
Methanol is an extremely hazardous chemical. Its Safety Data Sheet (SDS) notes the following hazards:
Section 2: Hazards Identification
Highly flammable liquid and vapor
Toxic if swallowed
Toxic in contact with skin
Toxic if inhaled
Causes damage to organs
Keep away from heat/sparks/open flames/hot surfaces.
Section 5: Firefighting Measures
Risk of ignition
Vapors may form explosive mixtures with air.
Vapors may travel to source of ignition and flash back.
(See the SDS for Methanol.)
Unfortunately, the specific hazards and firefighting measures information noted in the SDS are indicative and reflective of The Rainbow Experiment. To make things worse, teachers have been known to actually pour methanol from a stock bottle onto their demonstration table while an active flame is present. This is usually a recipe for disaster! As the SDS Section 5 warns, "Vapors may travel to source of ignition and flash back." The flames have been known to jet out several meters into the student audience, causing extreme injuries including setting clothes and hair on fire, melting skin, causing blindness, and more, for starters.
Numerous warnings have been issued in the past few years concerning the use of methanol and The Rainbow Demonstration. For example, the American Chemical Society (ACS) has a website titled Safer Experiments and Demonstrations that focuses on areas such as these:
In addition to providing critical information for science teachers on how to conduct safer experiments and demonstrations, the ACS also has a video titled A Safer "Rainbow Flame" Demo for the Classroom.
The National Science Teaching Association (NSTA) also has a safety portal with a variety of professional position statements and safety issue papers about appropriate criteria for experiments and demonstrations. NSTA also has a safety alert notice specifically about methanol titled Do Not Use Methanol-Based Flame Tests on Open Laboratory Desks.
Science teachers have a professional and legal responsibility to address preparation safety protocols before doing any lab activity or demonstration. The NSTA Safety Blog post titled Science Activity Safety Checklist, published on March 2, 2018, notes the following three steps to prepare for lab activities and/or demonstrations:
1. Hazard Analysis. Complete a Hazard analysis, and review SDSs. A hazard analysis is the first of three steps (hazard analysis, risk assessment, safety action) to determine the appropriate safety action. The SDS lists chemical hazards. Other sources for learning more about hazards include the NSTA E-Mail List Server (for NSTA members), the NSTA Safety Blog, and the NSTA Safety Portal.
2. Risk Assessment. Complete a risk assessment to determine what risks result from the hazards. If the hazard is a corrosive chemical such as an acid, for example, the risk is the acid’s potential to burn the skin or eyes.
3. Safety Action. Review and apply appropriate safety controls to address risks (elimination, substitution, engineering controls, standard operating safety procedures, class size, special-needs students, and personal protective equipment). Based on the risk assessment, take the appropriate safety action. For example, an acid would require students and teachers to wear indirectly vented chemical splash goggles, aprons, and nitrile gloves.
Teachers have not only a professional responsibility, but also a legal responsibility under duty or standard of care. There is a history of science teachers and their school districts being sued by parents of students injured in school lab demonstrations, including The Rainbow Experiment. Teachers, along with their school districts, have been found negligent, and in some cases, reckless, because they did not research the hazards and risks, nor did they provide the appropriate safety actions as required by legal safety standards (Occupational Safety and Health Administration [OSHA], NFPA, etc.) and better professional safety practices (NSTA, National Science Education Leadership Association [NSELA], ACS, etc.).
The internet has an abundance of information for science teachers and their supervisors relative to these required protocols, including those for The Rainbow Experiment. In some instances, teachers didn’t bother determining the hazards or risks; knew about the safety issues, but ignored them; though school boards have safety policies specific for science labs, the administration did not enforce them via the supervision process; and more.
These are just some instances of how duty or standard of care is not addressed, thereby placing teachers and their school districts in serious legal jeopardy, in addition to the physical and emotional harm done to students—and sometimes employees—resulting from extremely serious but preventable lab safety accidents.
Before considering doing any lab activity or demonstration, carry out the AAA approach to safer science: Hazard Analysis, Risk Assessment, and Safety Action. Don’t you or your students become injured by exposure to unsafe lab activities/demonstrations! Remember to "drive home safety" using the AAA approach.