Category: Blog post

Managing experimental scope changes

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 dkuespert@jhu.edu.

Got nanomaterials?

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

Warning: Graphite oxide explosions

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.

Warning: Azidophenylalanine

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.

Keep an accurate chemical inventory

 

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.

Learn the fundamentals of toxicology in your spare time

The National Library of Medicine makes available an online short course on toxicology available at https://toxtutor.nlm.nih.gov/index.html. ToxTutor even offers a certificate of completion if you sign up for the Library’s free learning management system.

Another good nonspecialist introduction to toxicology is The Dose Makes the Poison: A Plain-Language Guide to Toxicology (Frank, P., Ottoboni, M.A.; Wiley, 2011). This book provides an excellent introduction to toxic chemical hazards and is recommended for those who handle a variety of chemicals.

How to test an eyewash or drench hose station

Most of our labs have eyewashes or drench hoses (pull-out eye/face/body washes) for emergency use. These must be tested periodically. Drench hoses (which are part of the sink) or eyewashes with plumbed drains (most do not) are the responsibility of the laboratory. Here’s how to test a drench hose or eyewash:

Run the spray for 3 minutes or until the water runs clear, whichever is longer. If the water does not run clear immediately, the sprayer does not immediately actuate, pressure is too high or low, or if the water is not a tepid temperature, contact Facilities Management at x6-8063 as soon as possible to have the sprayer repaired. After testing the eyewash, clean the sprayer and any covers with alcohol wipes.

Log the test date, result, and any corrective actions taken. Logbook sheets must be retained until 2 years have passed from the last test recorded on them. A PDF form to use for logbooks is contained in the university policy on emergency equipment at  https://hpo.johnshopkins.edu/hse/policies/156/10941/policy_10941.pdf?_=0.719595961086. Keep the logbook near the drench hose/eyewash station or place a small sign nearby stating the location of the log.

It is fine to use a single logbook for multiple drench hoses in a large lab, but use separate pages for each drench hose and label the hoses so you can tell which is which.

Transporting chemicals

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:

  1. 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.
  2. 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.
  3. According to the National Academy of Sciences, carts used to transport chemicals should have at least a 2-inch lip to provide adequate containment.
  4. 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.
  5. Line the bottom of the tray or carrier with vermiculite or a spill-absorbent pad to help absorb minor leaks.
  6. 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.
  7. Do not transport incompatible chemicals (e.g., acids and bases) together in the same tray or carrier.
  8. 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.
  9. 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.
  10. 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.

Situational awareness

Situational awareness is having a “feel” for what’s going on around you—both the current state and how it might or will change in the near future. It’s a complicated topic (refer to Wikipedia for an introduction), but not having it can easily lead to incidents. I had a close call last year that occurred because I lost situational awareness.

I was photographing a worksite for a charity that recruits teams from disparate Howard County organizations varying from the County Police to church groups to employees of a well-known think tank to perform necessary repairs at the homes of the elderly and needy. It was at the latter’s “project house” that I almost got my brains knocked out.

The workers had removed a wheelbarrow full of soil from the yard while installing a new walkway, and they had procured a trailer to haul the soil and other debris away to the county landfill. I was standing at the front of the trailer taking pictures when the team hoisted the heavy wheelbarrow onto the trailer—setting it behind the axle. The resultant forces flipped the front of the trailer upward, and the trailer tongue (the metal bit that attaches to the tow vehicle) missed me by inches.

I had lost situational awareness—I failed to predict exactly what state my surroundings were in and in particular failed to predict how they were about to change. One can attribute part of this close call to “photographer’s hubris,” that is, the feeling that when one is behind the lens, one is indestructible. The major thing I failed to note, though, is that “charity home improvements” really means “construction site operated by amateurs,” and that I should be on my guard for dangerous conditions.

How often have you lost situational awareness—in the lab or on the road, perhaps? What was the result—did you have a close call, were there no consequences, or was there some sort of incident? What was the deciding factor in what the consequences were—chance?

Remember that in the lab we are all amateurs—so keep an eye on what you and your labmates are doing at all times.