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)
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 protected]for assistance in obtaining special cap systems suitable for your instrument.
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.
The unnatural amino acid azidophenylalanine is used for modifying and labeling proteins in biological and biochemical research. The azido group, though, is often a bad actor, leading to “energetic events,” (i.e., explosions).
A recent article in J. Org. Chem. (doi:10.1021/acs.joc.8b00270) by Mark Richardson, Gregory Weiss, and other University of California researchers describes an inexpensive synthesis of this amino acid. In the course of the research, the researchers studied the intermediates and final product using differential scanning calorimetry and discovered that azidophenylalanine “behaved like an explosive compound,” an unexpected result. The authors recommend that crystalline samples of azidophenylalanine not be stored for long periods and that all stocks of the material be kept in dilute aqueous solution.
Further details can be found in a Safety Note in Chemical & Engineering News.
Having an up-to-date chemical inventory is important for efficient laboratory operations, but it is essential for emergency responders. By agreement with the Baltimore City Fire Department, each JHU laboratory containing chemicals must post an up-to-date chemical inventory on the entry door. It is the lab’s responsibility to maintain its inventory.
In practice, the inventory need include only the full English common name of the chemical (or the IUPAC name if there is no common name) and maximum quantities stored or used in the lab. The inventory must be updated before the annual Health, Safety, and Environment inspection in the Fall, but best practices would be to update quarterly or monthly, depending on the rate of chemical transfer in and out of the lab.
Please make an effort to ensure that your laboratories meet JHU’s commitment to the Fire Department. Accurate information on a lab’s contents allows the Fire Department to protect themselves more effectively and to minimize damage to a lab experiencing an emergency.
There is often a need to move chemicals from room to room or between buildings. Hand-carrying hazardous chemicals can introduce a variety of ways that you, others, or the environment can be exposed. It is essential to transport chemicals properly in order to transport them safely. Tips for safe transport include:
- Carry bottles or jars in trays or bottle carriers instead of by hand—they are less likely to become broken, and the tray/carrier provides secondary containment.
- If using trays, push the tray on a laboratory cart instead of carrying it. Suppose you trip while executing the carry? A carried tray would fall and the contents would leak out.
- According to the National Academy of Sciences, carts used to transport chemicals should have at least a 2-inch lip to provide adequate containment.
- Do not crowd the bottle carrier or tray—trying to put two bottles in a single-bottle carrier or overloading the tray. This makes it more likely something will fall out.
- Line the bottom of the tray or carrier with vermiculite or a spill-absorbent pad to help absorb minor leaks.
- Bear in mind that some chemicals rapidly degrade or even explode in the presence of strong temperature changes or bright sunlight. Peroxide-forming chemicals are notorious for this if they have built up sufficient hazardous peroxides.
- Do not transport incompatible chemicals (e.g., acids and bases) together in the same tray or carrier.
- If moving chemicals further than the next lab, bring spill-management supplies along—the same spill kit you would use in your lab. Your quick action to clean up a spill can prevent a complex and expensive response by the JHU hazardous materials team or by the Baltimore Fire Department.
- When moving chemicals, it is a good time to verify that they have proper labeling: full chemical name, in English, is required (e.g., “isopropyl alcohol” instead of “IPA”). If there is not sufficient space to do this, use abbreviations and carry a key to the abbreviations with you to give to the new lab. Common chemical names are sufficient; full IUPAC nomenclature is not necessary.
- If the chemicals you are moving are heat-sensitive, package them in a box with a cold pack to maintain quality. If the chemicals may become shock-sensitive, consult with the Department of Health, Safety, and Environment before the move.
The American Chemical Society has revised the commonly-used Safety in Academic Chemistry Laboratories for its eighth edition. All those who handle chemicals should be familiar with the information in this small booklet, although it is aimed particularly at first- and second-year chemistry students. Hardcopies can be ordered from the American Chemical Society (http://www.acs.org) or a free PDF can be downloaded from here.
Some experiments take time: hours, days, even weeks. This means that the experiment will be set up and running in the lab while you are not there. You have an ethical obligation to prevent harm to others in the lab by ensuring that they are aware of your experiment and its hazards. Make sure they know:
- What the purpose of the experiment is;
- To whom it belongs;
- What behavior indicates that something has gone wrong; and
- What to do if something does go wrong.
You could tell the members of the lab all that information, but some lab members might not be present and others will promptly forget. Depending on the lab’s occupants to “know what’s going on” is foolish—your colleagues may know the general type of research you do but they are not familiar with the details of all your experiments. Far better is to post the information so that anyone in the lab can easily see what your experiment is, how to identify abnormal situations, and what to do in that event.
A sample form is available for you to use directly or adapt to your lab’s needs. (The file is in Word format for easy modification.) The form is written to allow use in teaching as well as research labs. You should prepare two copies of the form: one to post near the experimental apparatus and one to post in a safe place (like on the door). In an emergency, no one may be willing to approach the apparatus to read the information sheet!
Equipment being relocated must move through public corridors and outside areas; equipment being repaired or disposed is being transferred to service or disposal personnel unfamiliar with your lab and its hazards. In all cases, you are responsible for protecting others from unknown contamination. Learn more in Equipment Transfer Safety Note.