Category: Pointers Resources

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Do You Have Swiss Cheese In Your Lab?

Picture source: Ben Aveling, Wikipedia, CC-BY-SA-4.0.

One of the common models of safety incidents is the Swiss Cheese Model, due to James Reason. Generally, there are multiple different layers of protection between you and exposure to a hazard, and no safety barrier is 100% protective. The model treats hazards as passing through one or more pores in these safety barriers—hence the “Swiss Cheese” name. If the holes in the layers of protection happen to line up, and a hazard challenges them, there is a safety incident.

Things to learn from the Swiss Cheese Model:

  1. No safety barrier is 100% effective.
  2. Using multiple safety barriers generally decreases the incidence of safety incidents.
  3. This is only true if the safety barriers are independent, that is, if the “holes” do not line up.

So when you look at a hazard in your lab, ask: How many independent safety barriers are protecting me? Then consider if you might need additional barriers.

If you have questions about layers of safety protection and the Swiss Cheese model, 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.



Daniel R. Kuespert, PhD, CSP | Laboratory Safety Advocate (he)

Johns Hopkins University
Krieger School of Arts & Sciences/Whiting School of Engineering
Ames Hall 241, Baltimore, MD 21218
P. 410-516-5525 | E. [email protected]


Stanford Chemical Storage System

Proper chemical storage is a critical feature of a safe lab environment. Store only compatible chemicals together so that no unintended and potentially dangerous reactions occur. The Stanford Chemical Storage system is based upon the idea of storage groups: groups of chemicals that will not react violently if mixed together. 

Stanford Chemical Storage Groups are built-in for many chemicals in the BioRAFT inventory system. 

Checkout this PDF to explore the system and each storage group.  

ANSI Z136.5 and Z136.8 Update

The American National Standard Institute’s (ANSI) Z136 series is the leading set of safety standards regarding the usage of lasers. The most important of these standards to JHU are Z136.5 and Z136.8 which cover the safe use of lasers in educational institutions and research, development, or testing, respectively. This year, both standards have been updated, with the following changes: 

  • Demos and teaching experiments should use visible rather than invisible lasers whenever possible. 
  • All current laser warning signs must be brought up to modern standards. 
  • The Laser Safety Advocate must review all laser demonstration safety plans. 
  • Laser project review forms will now include the following topics: 
    • Recorded room interlock checks to ensure that all entry controls work as expected biennially. 
    • On-the-job training to provide information about best practices to help ensure that all researchers are trained to the same level and that experiments will be repeatable. 
    • Barrier testing – includes details on procedures and other recommended information 
    • A structured self-review process. 
    • Improved risk assessment protocols. 

Guidance for safe laser usage can be found here. 

For any questions about this update, please contact Laser Safety Advocate Niel Leon at 913-302-8500 or [email protected].   

Guidance for safe laser usage can be found here. 

For any questions about this update, please contact LSA Mr. Niel Leon at 913-302-8500 or [email protected].   

Quality Data for Safer Experiments

It is well understood that, especially in our digital era, proper collection and distribution of data is paramount for good science. This concept is especially important for data concerning safety analysis such as risk assessments and lessons learned reports.  

The following video released by the American Chemical Society (ACS) provides a fantastic introduction to this topic and contributes to our motto that safe science is good science.  

For further resources, visit the ACS Division of Chemical Health and Safety’s Quality Data for Safer Experiments page.  

Periodic Table of the Elements of Safety

The American Chemical Society (ACS) Division of Chemical Health and Safety has recently partnered with the Princeton University Department of Environmental Health and Safety to publish an updated version of the Periodic Table of the Elements of Safety. 

This interactive table, available to download in various sizes and formats, highlights some of the main hazard categories, risk assessment techniques, PPE, the Hierarchy of Controls, and other interesting information such as Safety Martyrs and Heroes. We encourage you to check out and share this valuable resource. 

Schenk Line Usage

Air and moisture sensitive experiments are a valuable part of inorganic chemistry. Tools such as the Schenk Line, a vacuum manifold connected to a vacuum pump, paired with an inert gas manifold connected to a source of purified and dry inert gas vented through a bubbler, allow for such experiments to be more easily carried out. However, information regarding the usage of this tool can be difficult to locate and access. 

To address this, Andryj Borys has released the Schlenk Line Survival Guide. This comprehensive free guide covers basic operations including setting up the Schenk Line and “cycling” along with some more complex procedures. Any researchers interested in air and moisture experiments, especially those that require usage of the Schenk Line, should check out this resource. 

You Only Get One Pair (of Eyes)

The title says it all: The Hospital is out of stock on replacement eyeballs, so it falls to you to protect the ones you have. Fortunately, you have your last line of defense—your eye protection. Remember which types are for which hazards (links below are examples, not recommendations; contact me if you need help choosing safety eyewear):

  •       Safety glasses protect against impact.
  •       Direct-vent safety goggles also protect against impact. If you wear prescription glasses and don’t have prescription safety glasses, this is your best choice for impact.
  •       Indirect-vent chemical splash goggles protect against impact and chemical splash. These are your only appropriate choice when working with chemicals.

Chemical splash goggles are required when handling corrosive chemicals or any chemical labeled as a hazard to the eye (e.g., irritants). You may be able to use safety glasses with mild chemicals such as buffer solutions, but remember that buffer solutions often have hazardous ingredients. If your eyes will be unhappy if you are hit with a splash, wear chemical splash goggles.

Safety goggles, particularly the indirect-vent kind, are prone to fogging internally, especially in hot, humid conditions (think Baltimore in August). There are three ways to prevent fogging: 1. Wear goggles with a built-in antifog protection. 2. If you have antifog goggles and they’re still fogging up, wash the goggles. Dirt and dust provide places for fog to nucleate on the lenses. 3. Use antifog wipes such as these, which are claimed to extend the fog-free time for antifog goggles by 60X!

If you have questions about eye protection, 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.

Available Laser Training and Self-Study Resources

Lasers are a valuable tool for conducting good science in the lab environment. However, safe science is good science, so it is incredibly important that all researchers using lasers understand their safe operation to avoid any incidents.  

Laser safety is a broad and comprehensive topic that requires proper training and materials to address. For information on laser safety training see here. This link will guide you through finding and taking the correct laser safety training depending on your role and exposure risk.   

Additionally, for more information or self-study materials, check out the Safe Laser Use page on the JHU Lab Safety websiteThis is your place to go for lab safety resources on the Homewood campus. We cover a variety of specific topics that you as a student or researcher must know.   

Finally, further information on general laser usage and safety, including relevant laws and regulation can be found on the Occupational Safety and Health Administration (OSHA) Laser Hazards page and the Laser Institute of America. These two sources provide a large range of additional training and reference materials for anyone interested in maximizing laser safety within their work and research environment.   

Contact Mr. Niel Leon, Laser Safety Advocate, at 913-302-8500 or [email protected] for more information about laser training and self-study resources. 

Lessons Learned Database

Understanding previous incidents, close calls, or potential shortcomings is crucial to not only establishing, but maintaining a safe lab environment. The U.S. Department of Energy’s (DOE) OPEXShare Lessons Learned database is a fantastic resource to find the most up-to-date news regarding safety errors and investigations from labs across the country. 

To access the database, first go to opexshare.doe.govHere you will not only find the Lessons Learned database, but also a collection of recent news stories and other content regarding lab safety. Once on the homepage, click the “Lessons Learned” banner which will redirect you to the database. From here, you can sort through lessons with categories such as type, topic, and site/group.  

Some of the more than 2800 lessons in the database include pressure vessel failure events and improper labeling. There is likely to be a situation or topic relevant to your lab.