How Safe are Rocks & Minerals in the Classroom?
Rock and Mineral Safety in Schools
James Palcik, OCT and Dr. Ken Roy
Every school on the continent has rock and mineral kits of varying ages and sizes that were provided or purchased to help students better understand the geologic world around them locally and across the country. Many of these in activity kit formats were provided by science supply companies as hands-on laboratory activity units for earth/space science and/or geology courses. They often were in concert with publisher science curriculum programs dating back to the 1960s. Other sets were provided by government agencies or as an educational resource from an industrial corporation to schools in a local area or across entire states. As noted, many of these kits have been used for decades and many specimens and samples are jammed into boxes and taken out sporadically as required during the school year to illustrate different types of igneous, metamorphic or sedimentary rocks or minerals. Some of these survey sets have a key that corresponds to the samples and a number or letter on the sample so that you can identify each of them easily. Sadly, many of these inventory keys have been ‘misplaced’ or lost making identification more difficult for many educators. Some of these older samples may actually be potentially hazardous and expose students and teachers to serious health and safety risks due to the fibrous, radioactive, or toxic metallic nature of the specimens making it a priority to know exactly what you have on-hand in these survey sets, kits, or boxes of random geology samples.
The concept of safety or approved standardized operating procedures for handling and examining these rock and mineral samples in science instructional spaces is rare –however there are some fundamental geological safety protocols/rules that you should be mindful of. Most science educators do not consider earth or environmental science to be as ‘hazardous’ as a pure chemistry or biology program, yet there are some substantial safety concerns involving the safer handling and examination or testing of these rock and mineral samples. These are the basic rules that should be followed and added to the Chemical Hygiene Plan (or Environmental Hygiene Plan) in your jurisdiction as standard operating procedures. Please be aware that based on the specific samples you have in your laboratory instructional space or science storeroom related space, there are some very special handling and storage requirements for those samples.
Safety Protocols When Working With Rocks and Minerals
Acid Testing
1. Acid testing with hydrochloric acid or nitric acid should be done using dilute acid with appropriate Personal Protective Equipment (PPE).
2. PPE required includes wearing indirectly vented chemical splash goggles meeting the ANSI/ISEA Z87.1 D3 standard, a nonlatex apron, and nitrile gloves during the setup, hands-on, and takedown segments of the activity.
3. Use only one or two very small drops of acid at the lowest molarity possible for a reaction. With tap water or distilled water, immediately rinse off rocks and minerals in a pail after performing the acid test. Neutralize the water upon completion of the testing with sodium bicarbonate. Blot the specimens dry using paper towels.
4. When diluting acids or bases, the acid or base should be added to water and not water to the acid or base.
5. Know where the eyewash/acid shower stations are located and how to use them in case of emergency. 6. Be certain to wipe up any water or other liquid spilled on the floor to prevent a slip/fall hazard.
7. Never pour chemicals, either used or unused, back into their original container.
8. Only combine substances and amounts as instructed by your teacher.
9. Follow your teacher’s instructions for disposing of waste materials.
10. Wash your hands with soap and water immediately after completing this activity.
Bead tests: When using flame or borax bead tests for identification of rocks and minerals, always use appropriate PPE. PPE requirements include wearing indirectly vented chemical splash goggles meeting the ANSI/ISEA Z87.1 D3 standard, a nonlatex apron, and nitrile gloves during the setup, hands-on, and takedown segments of the activity.
Dust hazards: Clay, rock, mineral, and sand dust all have Threshold Limits Values (the reasonable level to which a worker can be exposed without adverse health effects) and are therefore potential chronic respiratory health hazards. When working with these materials, do so only under the fume hood, spray booth or outdoors. Talc is often used to demonstrate the Moh’s Hardness Scale, and the fine talc powder can be accidentally inhaled causing harm. The fine particle dusts from quartz compounds can cause significant medical harm including silicosis resulting from inhaling the fine dusts. Each rock and mineral sample will have its own unique hazards resulting from the fine dusts created by cutting or cleaving specimens.
Field trips: Geology fieldwork is potentially hazardous given the inherently dangerous locations for trips, such as cliffs, excavations, and quarries. Consult with the “Code for Geological Fieldwork” by the Geologists’ Association (www.geoconservation.com/GCCdocs/field workcode.pdf) prior to planning and taking the trip. Always ensure that you review the expected behaviors with the attendees before and during the field activity and use a safety acknowledgment form to be reviewed and signed by both students and their parents or guardians as a additional layer of the safety program. Make sure Board of Education safety policies are reviewed in advance and followed.
Hand washing: Always wash hands with soap and water after conducting earth/space science or geological studies hands-on activities, especially after handling rock and mineral specimens. This is a non-negotiable aspect of safety in the geological laboratory.
Heat sources: Bunsen burners should never be left unsupervised during use. Make sure gas connections are correct and emergency gas shut-off switches and levers are operational. Natural rubber tubing shall not be used for Bunsen burners because it is susceptible to cracking. Only use tubing meeting the National Gas Association’s standard including fabric-reinforced PVC or fabric-reinforced neoprene (polychloroprene). Inspect electrical cords on hot plates for damage.
Ensure all electrical receptacles are GFCI protected to prevent shock. All heat sources should be turned off when not in use. Never handle hot materials directly with hands; use tongs. Always point liquids being heated away from the users and those nearby. Some mineral compounds when heated may release toxic compounds such as Cinnabar. Like many minerals, Cinnabar can decompose thermally, meaning that if you were to cook it at a sufficiently high heat, it will break down and may release toxic vapors. Grinding these minerals can also cause similar risks, likely because of local heating caused by friction. Do not heat your minerals, as heat may cause reactions with dangerous byproducts unless you are aware of the chemical and thermal reactions of the samples you are using!
Also, work very carefully with open flames and never inhale the vapors emitted from the rock or mineral sample. Never use conventional alcohol lamps as heat sources—they are unsafe and unreliable and pose a serious risk to occupants and users.
Hot rocks: Avoid radioactive minerals (e.g., uranium-type ore), which can be a health risk if direct exposure occurs. Never use these types of samples in the open instructional space —radioactive types of minerals require special protocols and should be used very carefully. You cannot see radiation – yet it is a hazard which may cause significant medical harm to people in proximity. *If a school still has older radioactive isotope samples, a wooden lead-lined lockable box or a Geiger counter, please advise the CHO (Chemical Hygiene Officer) of this discovery and arrange for appropriate safer disposal* Many states also have radiation officers who can be called on to determine if any of the rock samples pose a radioactive hazard/risk to students and their teachers.
Lubricants: Refractive-index oils and rock-saw lubricants are considered low risk chemicals, but still require PPE to be worn properly by the person(s) handling these liquids for investigating rock and mineral samples. If any of this lubricant should spill, use appropriate oil clean up procedures found in your Chemical Hygiene Plan.
Machines: Machines such as rock crushers, splitters, and grinders, as well as power drills and saws, can be potentially hazardous to operate. Make sure guards are in place and users have proven competency to operate the machines independently. Safety work zones outlined on the floor need to be established for the machine operator. Many power tools, such as rock saws, are too dangerous for use in a classroom, and no power tool should be used unless a proper setting and strict safety training can be provided. Appropriate PPE is essential. PPE requirements include wearing safety glasses with side shields or safety goggles meeting the ANSI/ISEA Z87.1 D3 standard during the setup, hands-on, and takedown segments of the power tool use.
Remove all loose jewelry, tie back long hair, and do not wear loose clothing. Only allow students to handle tools or machinery once they have been trained in the safer operation and can demonstrate that to the instructor PRIOR to using this equipment independently under supervision. Many power tools/machines require dust collection systems (e.g., wood dust, metal dust and aluminum dust) to prevent particulate exposure to machine operators, and help prevent fire hazards.
Metal and mineral hazards: Some samples of rock contain lead hazards and others contain the mineral asbestos. These types of rocks should never be handled during a laboratory activity. Additional prohibitions apply to minerals containing ores of arsenic and mercury. Please note that Pyrite is iron sulfide; Chalcopyrite is copper iron sulfide; Galena is lead sulfide; Cinnabar is mercury sulfide; and Sphalerite is zinc sulfide. These compounds do contain recognized heavy metals, however due to the chemical bonding in these samples, these are mostly stable and insoluble in water which reduces the risk of handling these specimens greatly. Through the use of appropriate PPE (especially hand protection) and performing a potential hazard safety analysis and resulting health and safety risk assessment prior to planned activities to reduce the potential for accidental injury or exposure, these earth and space science laboratory activities can proceed under direct supervision when the analysis demonstrates that the educational value exceeds the subsequent resulting risks.
*If you have any ASBESTOS samples, these should NOT be handled in schools, whether these were part of a commercial rock and mineral kit or survey set, due to the inherent risks associated with asbestos fibers. Special care should be taken with Quartz (Silicon dioxide) dusts which can also contribute to chronic medical conditions such as silicosis impacting lung function.*
Microscope use: Be careful when carrying microscopes so as not to drop and cause foot damage; also, the cord can be a trip and fall hazard. Lastly, use only ground fault circuit interrupters (GFCI) protected circuits to prevent accidental shocks.
Mineral hardness test: Use caution in working with a nail or sharp metal probe to determine mineral hardness. These tools can cut the skin allowing for infections, such as Staphylococcus or Clostridium tetani. If a glass plate is used, hold the plate flat against the lab desk to do the test and use caution with sharp edges while ensuring that there is nothing under the glass plate that may cause a breaking point.
Observation of rocks and minerals: When investigating rocks and minerals, remember to use appropriate eye protection (safety glasses or chemical-splash goggles rated with the ANSI/ISEA Z87.1 D3 2020 standard for impact) before using hammers or other tools. Never place any geological specimens in your mouth—this includes tasting minerals for purposes of identification.
Safety Data Sheets: These must be available and reviewed prior to use of any potentially hazardous chemical in the laboratory or classroom instructional space including geological samples.
Stream tables: Make sure eletrical sources for stream tables are protected with a GFCI wall receptacle, which will prevent electric shock in most instances. Immediately wipe up water spilled on the floor, which introduces a slip and fall hazard situation if not addressed immediately.
Soil and hygiene: Obtain soil samples from known sources, due to possibility of industrial contamination of collected soil, pesticides, mold, bacteria, and other pathogens. The use of soil testing kits for lead, arsenic, metals, salts (halogens) and other biological hazards must be considered before allowing students to handle or examine these soil samples out of an abundance of safety. Make sure PPE requirements include wearing safety glasses with side shields or safety goggles meeting the ANSI/ISEA Z87.1 D3 standard during the setup, hands-on, and takedown segments of the power tool use.
Final Thoughts on Rocks and Mineral Safety
Geology can be an exciting study for high school, middle school and elementary students. Performing hands-on investigations and making accurate observations serve to help educate students and help them connect scientific principles to the word around them. Remember that all laboratory instructional space work and field studies should be engaging and safer simultaneously. As the instructor, you must review all necessary laboratory safety procedures with students prior to conducting laboratory work and provide safety updates specific to each activity. Modelling acceptable safer techniques and behaviors is one of the best ways to ensure that your students have a safer and successful experience in the geology laboratory or classroom instructional space. Remember to make a notation of your communicated safety instruction in a lesson plan or daybook as a source of ongoing safety evolution in case of any potential future liability issues.
Stay safer! Safety First, Accidents Last.
Reference
Investigating Safely: A guide for high school teachers. Texley, J., T. Kwan, and J. Summers. 2004. Arlington, VA: NSTA Press.
Geology: Rock Solid Safety (NSTA 2008 Dr. Ken Roy Safety Corner: March 2008)
EPA article Radioactive Material in Science Classrooms, https://www.epa.gov/radtown/radioactive-material-science-classrooms
