An article in the American Chemical Society’s Chemical & Engineering News newsmagazine draws attention to the hazard posed by sodium hydride when used in certain polar aprotic solvents such as dimethylsulfoxide (DMSO) and dimethylformamide (DMF). Although these hazards have been known for fifty years, it appears that use of NaH with these solvents is common, judging from the large number of published syntheses that use them together. It is recommended that NaH not be used with polar aprotic solvents at all. See https://cen.acs.org/safety/lab-safety/Chemists-continue-forget-safety-concerns-about-sodium-hydride/97/web/2019/08 for more detail.
Sometimes while we are in the lab, unanticipated safety issues arise: you find an uncapped bottle of chemical waste in the fume hood, notice that a machine was not cleaned and locked out after use, or see that someone isn’t wearing the personal protective equipment specified by the principal investigator or by the Department of Health, Safety & Environment. Instead of just proceeding with your work, this is an appropriate time to “hit the Pause Button” on your work and perhaps that of others.
By “hit the Pause Button,” I mean to stop working temporarily and ask anyone else affected to do so as well. You have the right and the responsibility not to work unsafely or under unsafe conditions. While Johns Hopkins can be fined for providing a workplace not “free from recognized hazards,” [language from the OSH Act of 1970] employees (and that may include graduate students) can also be fined by Maryland Occupational Safety and Health for not complying with occupational safety and health regulations. [Maryland Code 5-104(b)(2)] Such a fine is unusual, but not unknown.
If the safety issue relates just to you, you may be able to resolve it easily by yourself—capping the chemical waste bottle mentioned above, for example. If not, consult with your principal investigator to determine how best to handle the situation. If the PI is not available, you are not permitted to continue work—the workplace must be free from recognized hazards before you begin work and while the work continues. (Alternatives to contacting the PI include contacting your department’s faculty safety officer, the Lab Safety Advocate, or the Department of Health, Safety & Environment.) Note that if you resolve an unsafe situation yourself, you must still report the occurrence to your PI; the PI needs to know to prevent the condition from occurring again.
More complicated is if the safety issue involves someone else. A colleague who fails to put on a lab coat and eye protection because “I’m just going to do this one little thing” is taking unnecessary chances. If you observe that individual doing something you know is wrong, and he or she becomes injured, part of the fault is ethically yours. In addition, someone who takes shortcuts like skipping personal protective equipment may take more shortcuts—some of which could endanger you!
Politely point out the at-risk behavior and request that your colleague rectify the situation. If you’re not certain the behavior is risky, ask your colleague to explain the situation to you. Many people, particularly those who have just forgotten (as opposed to deliberately avoided a safety measure) will be grateful for the reminder. If the person refuses to work safely, contact your principal investigator or the Department of Health, Safety & Environment (410-516-8798) for assistance. The Laboratory Safety Advocate, Dr. Dan Kuespert, CSP (firstname.lastname@example.org) is also available to PIs for consultation on handling personnel exhibiting repeated at-risk behaviors.
The safety of what goes on in your lab is your responsibility—whether or not you’re the one conducting the work. Be willing to speak up and “hit the Pause Button” when necessary to protect yourself and your colleagues.
The JHU Department of Health, Safety, and Environment (HSE) is now offering training in the use of portable fire extinguishers to extinguish “incipient” (early-stage) fires in offices. JHU does not normally permit employees or students to use extinguishers (they are present because of fire code requirements, not so that they can be used by untrained persons). Passing this training renders the learner qualified to use fire extinguishers for a period of one year. (Training at annual intervals is legally required.)
The course is a blended live-online offering provided through myLearning. Those wishing to take the course should first take the myLearning online course titled “Using Fire Extinguishers at JHU Homewood.” This course imparts all the information necessary to know in order to use extinguishers safely. Learners should then sign up for the course titled “Using Fire Extinguishers at JHU Homewood (Instructor-Led).” This course provides live hands-on experience with a real fire extinguisher on a simulated fire.
Both courses are necessary for a learner to be considered “qualified” to use fire extinguishers in offices.The courses are quite short and will not take up excessive amounts of time. As mentioned above, qualification lasts one year and may be repeated annually. Those who have not taken this course in the past year shall NOT use fire extinguishers under any circumstances.
No one at Homewood is required to extinguish or fight fires. Always consider your safety and that of others over the safety of property, data, samples, etc. The preferred action is always to evacuate.
Note that this course does not qualify a learner to extinguish incipient fires in laboratory environments.Development of such a course is in progress, but the appropriate response to a laboratory fire is often to leave the building, not to attempt extinguishment. Lab fires can produce dangerous toxic vapors, explosive conditions, and involve chemicals that react with standard extinguishing agents.
Also note that undergraduate students are forbidden from using fire extinguishers at JHU Homewood. Undergraduate students may sign up for the courses for their own enrichment, but they must understand that they may under no circumstances use extinguishers at Homewood.
Many labs at Homewood use High Performance Liquid Chromatographs (HPLCs); these instruments allow separation and analysis of a wide variety of chemicals in small quantity. HPLCs use carrier solvents, chemicals that carry the compounds being analyzed through the machine. Consequently, HPLCs can produce large amounts of chemical waste. This can lead to several problems.
- Laboratories sometimes place HPLC waste containers on the floor where they can be kicked. Not only can this cause a chemical spill, but it can also result in physical injury to researchers to accidentally kick or trip over the waste bottle. This risk is easily mitigated by placing the waste containers off the floor—on the bench, in a cabinet, etc.
- HPLC waste containers are sometimes stored without secondary containment, that is, a tray or outer bottle to prevent leaks from spreading. Secondary containment must be large enough to contain the entire contents of the leaking waste bottle, and it must be made of a material (usually plastic) resistant to the chemicals it might have to contain.
- Sometimes, laboratories will route HPLC waste lines directly into bottles such as recycled solvent bottles. While there is nothing wrong in principle with this, there are several issues.
- Often, the tubing is routed into the waste bottle without any consideration for overflow. Special purpose valves, often built into specialty bottle caps, are available to shut off flow in the waste line if the waste bottle fills up. Most HPLCs will shut themselves off if the waste line is blocked—check your instrument manual.
- Sometimes, the tubing is secured and “sealed” to the bottle with aluminum foil or Parafilm—this is ineffective in stopping vapor from being released into the lab. The result is that all lab occupants must breathe the vapor from the HPLC waste; this is also an environmental violation. Again, special HPLC collection systems and bottle caps are available to provide a positive seal.
- Using recycled bottles can also be an issue if the original contents of the bottle are not compatible with the HPLC waste. Never use reactive chemical bottles such as those for nitric or perchloric acid for solvent waste, regardless of how well you think you’ve cleaned them.
Secondary containment tubs and overpacks are available from laboratory equipment suppliers such as Fisher Safety. Other suppliers, such as Cole-Parmer, make sealed HPLC cap systems. Contact the Laboratory Safety Advocate, Dr. Daniel Kuespert, CSP, at email@example.com assistance in obtaining special cap systems suitable for your instrument.
Ever wonder how to justify the time it takes to do hazard and risk assessment on your work? The American Chemical Society just posted this short video discussing the why of hazard and risk assessment (and what the difference is between them).
Have a look at the video–and learn how crossing the street relates to lab experimentation.
All experimental protocols have a scope—that is, every experiment has parameters such as pressure, temperature, power, force, chemical identity, etc.
Many people think that performing safety analysis on an experiment is “too much trouble” because they don’t want to have to do it each and every time they change a parameter. This is not true; such people misunderstand how to use safe experimental design methods.
When we plan an experiment, the range of parameters we expect—pressure ranging from 0 to 50 bar, for example, defines a set of safe operating conditions– what I like to call a sandbox. Provided you do an appropriate safety analysis for the range of safe operating conditions you expect to use in your experiment, you can do experiments anywhere within the sandbox you like. Want to move your 5 bar experiment to 15 bar? If your safe operating pressure is defined as 0—50 bar, no additional safety analysis is necessary.
It is only when we leave the sandbox—vary parameters outside the range we’ve already studied—that additional safety analysis is needed. Recognizing when you have a need to vary outside your known safe parameters and doing the appropriate safety analysis—expanding your sandbox—to verify that the variation is safe is called Management of Change.
So an efficient and safe experimental design takes into account the widest anticipated variation in parameters—it makes the sandbox as big as possible. This requires a little thought at the beginning of an experimental series: exactly how hot might you need to operate? Exactly which chemical solvents might you need to use? It takes far less time to do safety checks on a broad scope of experimentation than to do smaller ones piecemeal during lab work—and it is far more likely to be done properly because you won’t be in a hurry to get back to the bench.
If you would like assistance in safe, efficient, broad-scope experimental design, contact the Laboratory Safety Advocate, Dr. Daniel Kuespert, CSP, at firstname.lastname@example.org.
Nanomaterials pose challenging health & safety issues, because the toxicity and other biological effects of many nanomaterials are unknown. It is entirely possible that nanomaterials can be much more dangerous than the base materials. For example, a lump of coal or a diamond is relatively nonhazardous, but carbon nanotubes have long been suspected of asbestos-like action on the lungs, leading to lung and pleural lining cancers. [https://blogs.cdc.gov/niosh-science-blog/2008/05/20/nano/]
The Centers for Disease Control and Prevention’s National Institute of Occupational Safety and Health recently issued four documents describing best practices for working with nanomaterials, including [items from CDC press release cited below]
• Handling and weighing of nanomaterials when scooping, pouring, and dumping;
• Harvesting nanomaterials and cleaning out reactors after materials are produced;
• Processing of nanomaterials after production;
• Working with nanomaterials of different forms, including dry powders or liquids.
The last item, working with nanomaterials, comes in a poster format suitable for hanging in the lab; the others are guidance documents.
It is strongly advised that researchers and principal investigators working with nanomaterials familiarize themselves with these documents, since they represent known best health & safety practice for their work.
The documents may be found on the CDC website at https://www.cdc.gov/niosh/updates/upd-03-12-18.html
Graphite oxide (GO; also known as graphene oxide) is an intermediate compound used in its own right and as a route to graphene. Several papers over the last few years have indicated that bulk GO, when heated, can explode; samples of a few milligrams created energy releases that damaged laboratory equipment. (Qiu, Y., et.al. Explosive thermal reduction of graphene-oxide based materials: Mechanism and safety implications. Carbon 72, 2014, pp215-223. Doi: https://doi.org/10.1016/j.carbon.2014.02.005)
Self-heating is also possible, particularly with addition of dopants such as hydroxyl ions (-OH), which drop the temperature for thermal runaway by as much as 50˚C. Such a reduction can overlap with common processing temperatures for GO.
Results presented at the recent American Chemical Society meeting in New Orleans (Green, M.J., et.al. Study of safer storage of graphene oxide. Paper number CHAS 3.) indicate that the temperature at which thermal runaway/explosion occurs drops as the amount of material increases due to mass and thermal transfer effects.
Storage of substantial quantities of GO therefore may pose both a laboratory and a process hazard. It is recommended that researchers working with this material minimize storage, perform a thorough literature search before heating GO, and take appropriate precautions to protect against mishaps.
Laser eye protection is normally rated using continuous-wave, narrow-bandwidth lasers. Nevertheless, some labs use pulsed lasers, which have wider bandwidths and higher peak powers; in the case of pico- and femtosecond pulses, this is taken to extremes.
Recent work at NIST and Hood College in Frederick, MD, has shown that much laser protective eyewear is not capable of withstanding fast laser pulses. (J. Laser Appl. 2017, DOI: 10.2351/1.5004090) 22 different pairs of eye protection were tested against a 40-80 fs pulsed laser, and more than half failed to perform as rated. All plastic protective lenses failed.
It is strongly recommended that when selecting laser protective eyewear, you test the eyewear against your particular use condition to ensure that they provide adequate protection. The Laser Safety Advocate, Niel Leon, is available to assist with testing of this sort.
Further information can be found in the cited paper and in this article in Chemical & Engineering News.
Hazard assessment is an important part of the overall process of controlling hazards in the laboratory. The American Chemical Society recently developed a website that gives detailed information and tools for doing hazard assessments–tools that apply not only to chemistry but to all laboratory research.
I encourage all researchers to look at the ACS’s site to see what lessons can be learned. If you would like an introduction to the resources available or a “teach-in” on a particular part (e.g., standard operating procedures–what we call “experimental protocols” in academia), please contact me at email@example.com.