Teachers understandably want to make learning about science fun and exciting, and chemistry teachers in particular have perpetuated a long tradition of wow-factor demonstrations involving fire. When such demonstrations are performed, students, being naturally curious, want to see what’s happening up close, and they gather around the bench to see the changes that are occurring. In most incidents where students are injured, there is no barrier to protect them. Teachers often do not require that students wear personal protective equipment (PPE) such as goggles and aprons during these demonstrations, even though such equipment might be required during student lab work. Many teachers are also inadequately trained in lab safety procedures.
There is often a large amount of flammable alcohol present. Many of these events have been related to the use of methyl alcohol (methanol), a highly flammable liquid that burns with little visible flame, and many of the demonstrations have involved one-gallon bottles of methanol. Accidents occur when the demonstration isn’t working as the teacher planned, or when the students want to see the demonstration again. A bottle of methanol is opened to pour more of the liquid into a dish or beaker that contains an active flame; the flame ignites the methanol vapor and the fire flashes back into the bottle, spraying the burning methanol out of the bottle and onto the nearby students. While other types of science lab incidents result in burns, chemical inhalation exposures, and other injuries for students and teachers, the proximity of unprotected students to fire demonstrations often results in some of the worst incidents in terms of the numbers of students involved and the severity of their injuries.
Tattoo on Weber's foot of the molecular structure of methanol. Photograph: United States Chemical Safety Board.
The new requirements in Chapter 12 of NFPA 45 are retroactive to all schools and apply to the performance of science demonstrations using hazardous materials. The requirements include instructor responsibilities, chemical handling and storage requirements, and controls for the performance of demonstrations. The requirements below are similar to the requirements that the CSB recommended last October.
» Teachers are required to perform a hazard risk assessment prior to performing each demonstration. The assessment will identify the hazards associated with the demonstration, the prudent practices needed to minimize the risk, the PPE needed for the instructor and the students, safety equipment needed for the demonstration, and emergency procedures. Teachers need to be trained and knowledgeable in fire safety procedures, school emergency procedures, appropriate use of PPE, and how to conduct hazard risk assessments. Teachers need to train their students annually on the school’s emergency and fire prevention plans, including procedures for extinguishing clothing fires.
» The requirements for handling and storing chemicals in school labs include storing and handling bulk quantities of chemicals in a separate room outside of the classroom. Chemicals that will be used in the classroom will be prepared before the students arrive and pre-apportioned in sealed containers or eye-dropper bottles in the amount that is needed for each demonstration. Chemicals that are not in use need to be locked in appropriate storage cabinets.
» Demonstrations that involve open flames, fire, or the use of flammable, reactive, toxic, or corrosive chemicals must be performed with a barrier or adequate separation between the students and the demonstration. Demonstrations that produce hazardous amounts of gas, vapor, fumes, or particulates must be performed in a chemical fume hood or with other types of ventilation that will protect the students from the hazard. Many laboratory vendors provide demonstration-type chemical fume hoods and demonstration enclosures that allow the students to watch the demonstration without being exposed to the hazard. Other demonstrations performed on benchtops need to be performed behind a transparent barrier or with at least 10 feet of separation between the students and the demonstration. Lower-cost demonstration hoods/enclosures and benchtop shields are available that allow students to watch the chemical reactions without being exposed to the hazard if something goes wrong.
» So that students will be able to get out of the lab quickly, demonstrations must be performed in a location that will not block access to the exit(s) from the laboratory.
It is widely understood that many school districts around the country operate with very limited budgets and cannot afford to buy new equipment for their labs and provide the necessary training for their teachers. While it is important to acknowledge those limitations, we cannot afford to burn any more students in science demonstrations. These accidents are preventable. There are many organizations that provide low-cost training materials and safety programs for school science programs, including the Laboratory Safety Institute (LSI), an international nonprofit education organization for laboratory safety that provides low-cost laboratory safety training and reference materials for schools. The Laboratories Using Chemicals committee has worked with the LSI to review the new requirements to NFPA 45.
The new requirements in NFPA 45 will only be effective if the standard is adopted by the state and local fire departments. If NFPA 45 is not adopted in its entirety, at a minimum the operational requirements in Chapters 6, 11, and 12 of NFPA 45 need to be adopted to provide safe practices in all laboratories, especially for K–12 magic shows, demonstrations, and laboratory activities. After adopting NFPA 45, the fire marshals, fire inspectors, and science teachers need to be trained on the new requirements to improve the safety of laboratory demonstrations.
By working together to implement these safety controls, we will be able to protect our students from being seriously injured in the event of an accident involving flammable liquids or hazardous chemicals. There is no reason for students to be burned while watching science demonstrations.