Author: Dan Kuespert

Laboratory Safety Advocate for the Johns Hopkins University Homewood Campus. I am a Ph.D. chemical engineer and Certified Safety Professional with experience in industrial research, nonprofit management, and chemical safety consulting. My role is to promote a culture of safety at Homewood by working with faculty, staff, and students to bring safety expertise into the laboratory.

Close calls

For every serious safety incident, there are typically several situations where a safety barrier such as a chemical fume hood, a machine guard, or someone’s eye protection is tested, but holds, preventing the incident. These situations are called close calls, and they are extremely valuable to our safety program.

If you experience a close call—a splash intercepted by your chemical splash goggles, a part flying off a machine and missing you, or a chemical fume hood failing during an experiment—please report it to Dr. Daniel Kuespert at [email protected]. Dr. Kuespert or someone he has trained will respond to you promptly and help you investigate the close call. We do this in a blame-free environment; we’re only interested in your safety and that of others.

We sometimes find that apparently-simple close calls show up systemic flaws that could have caused larger numbers of incidents. Whatever the true causes of the close call, we cannot help you correct them if we do not know about it! The [email protected] address goes only to Dr. Kuespert, and you can remain anonymous—just note that in your report.

If you have questions about close-call studies, contact Dr. Daniel Kuespert, Homewood Laboratory Safety Advocate, at [email protected]. See Dr. Kuespert’s website,, for more safety information. As always, emergency response is available from Security at 410-516-7777.

Keep the Safety in your “Health & Safety”

COVID-19 has brought many new challenges to work in our laboratories, and it is only natural that attention focuses on the new risks. Nevertheless, it’s important to remain vigilant about old risks—the “routine” laboratory safety hazards that occur daily in a science or engineering lab.

Because these old hazards—tools & equipment, hazardous chemicals, biological agents other than COVID-19—are still here and still pose the same risks, we need to maintain awareness of those risks. Established safety procedures ( still apply. Some hazards have become enhanced because of the coronavirus—many more people are working alone in the lab, for example.

If you have questions about how to adapt your work and current safety procedures to work well with the COVID-19 precautions, contact Dr. Daniel Kuespert, Homewood Laboratory Safety Advocate, at [email protected] See Dr. Kuespert’s website,, for more safety information. As always, emergency response is available from Security at 410-516-7777.

Serious lab allergies from peptide coupling agents

The Journal of Organic Chemistry is reporting a case of severe allergic reactions (i.e., life-threatening anaphylaxis) developed to reagents used for peptide coupling (assembling short proteins). Any lab worker using HATU, HBTU, or HCTU, three uronium coupling agents, should read this link and speak with his or her PI regarding any necessary changes to use protocols. Also please contact Dan Kuespert, Homewood Laboratory Safety Advocate, for assistance.

(J. Org. Chem. 2019, DOI: 10.1021/acs.joc.9b03280)

Unattended Experiments

Do you leave experiments running after-hours or over the weekend? Are you ready in case an incident might occur? Establishing clear procedures for late or unattended work may help prevent a minor incident from becoming a serious one. See this article by Richard Paluzzi, a noted lab safety expert, for more detail.

The Laboratory Safety Advocates Office has developed an unattended experiment form that you should fill and post on the laboratory door and next to the experiment. If you have questions about filling out this form contact your PI, laboratory manager or the Laboratory Safety Advocates Office.

Sodium hydride decomposes certain solvents-violently.

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 for more detail.

Hitting the “Pause Button”

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 ([email protected]) 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.

Office fire extinguisher training now offered by HSE

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.

HPLC waste handling

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.

  1. 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.
  2. 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.
  3. 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 protected]for assistance in obtaining special cap systems suitable for your instrument.