Evolution of an Hazmat Acronym

A new acronym was complete; "4H MEDIC ANNA" was born.


The last letters I had were two A's and two N's. I found that they easily formed "ANNA" and now the medic at the 4H fair had a name. The new acronym was complete! "4H MEDIC ANNA" was born and could now easily be remembered as the 13 gases that were lighter than air. That bolt of enlightenment, that new paradigm, came several years ago and a few years later I even wrote about the acronym for Firehouse.com in December 2001.

Since that initial article from over six years ago, several authors have used the acronym in their books, training manuals, Powerpoint programs, public presentations, and articles. My humble little acronym is now published in such books as Managing the Incident by Mike Hildebrand and Greg Noll, the International Association of Fire Fighter's First Responder Operations Course student manual, Michael Callan's presentations on Pipeline Emergencies, Frank Docimo's presentations on metering devices and many, many others. You can also find it in a search on the net. It is even defined at Wikipedia, and the merits of the acronym can be found discussed at numerous websites, blogs, and chat rooms.

What is this about? It is not about vanity, nor is it about compensation. It is not about being singled-out or to proudly strut around proclaiming to be the "be-all, end-all". It is merely to encourage others to freely and openly give of their research and knowledge. By doing so, it makes us all better, and safer, and more efficient. You see no one has the market cornered and has all of the wisdom, knowledge, experience, and courage. In fact, it takes courage to step forward and put your words and thoughts out there because there are plenty of critics who will try to shoot you down. So, like all of the other words that you find at this website, in this section, and the words that first described and offered the acronym "4H MEDIC ANNA", they have all been offered with equal amounts of altruism and humanity to the greater response community. I encourage you to also share your ideas and innovations and maybe someday your efforts will help to make new paradigms. Be careful out there!

As usual, please share your thoughts or questions with the author at dcnkm@charter.net or the website www.hazmatpetie.com.

The FDNY's flammable- and lighter-than-air gases are; hydrogen, acetylene, hydrogen cyanide, ammonia, methane, illuminating gases, carbon monoxide, and ethylene.

The complete "4H MEDIC ANNA" acronym with vapor densities:

  • Hydrogen (diatomic molecule)....MW is 2............VD is 0.07
  • Helium.....................................MW is 4...........VD is 0.14
  • Hydrogen Cyanide.....................MW is 27..........VD is 0.93
  • Hydrogen Fluoride.....................MW is 20..........VD is 0.69
  • Methane..................................MW is 16..........VD is 0.55
  • Ethylene..................................MW is 28..........VD is 0.96
  • Diborane..................................MW is 27.7.......VD is 096
  • Illuminating Gases....................MW is 17.4........VD is 0.6
  • Carbon Monoxide......................MW is 28..........VD is 0.96
  • Acetylene.................................MW is 26..........VD is 0.9
  • Neon.......................................MW is 20.2........VD is 0.7
  • Nitrogen...................................MW is 28..........VD is 0.96
  • Ammonia.................................MW is 17..........VD is 0.59

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DAVID PETERSON, a Firehouse.com Contributing Editor, is a 28-year fire service veteran who serves as a lieutenant and training officer in Madison, WI, and as the training coordinator for the department's regional Level A HazMat team. David founded the Wisconsin Association of Hazardous Materials Responders, Inc. and teaches, presents, and authors articles on a wide variety of fire and hazmat topics. David is also a National Fire Academy instructor of chemistry and a Master Instructor for the International Association of Fire Fighters HazMat and Terrorism training programs. To read David's complete biography and view his archived articles, click here. You can reach David by e-mail at dcnkm@charter.net.