Natural Gas Propane Leaks… You don’t know…what you don’t know

   Not knowing what I did not know about proper response to gas leaks almost killed me and my captain. It was a routine, annoying natural gas leak until the house blew up, make that, was shredded and strewn over the property, and us with it.

   We were lucky to survive, close enough to the house for the concussion to knock us down while major parts of the house flew over our prostrated bodies in the lawn but far enough away not be picking the doorknob from our skulls. We were lucky.

   The good news is driven by post traumatic growth, Dan Moran and I spent years working thru the details of what I should have known and done that day. We have built a very successful one day training program using this hard won experience. Here are a few things of the many you probably don’t know but need to know to adequately respond to releases of explosive gases like natural gas and propane.  By the way, it’s not your fault you may not know these facts below: it is not in any of our training programs and your training on the 4 gas meter and your sop is likely weak, so how could you know!

   Here are just a few you need to know.  For more information see the Fire Engineering Magazine articles we have published.

   1. Procedures: do your FD sops mirror the gas company’s procedures? Gas co procedures are public documents. Ask your gas rep for a copy to help you re-write your sop…. if they will not share, FOIL them thru the regulating agency. They are public documents that you have a right to see.

   2. Why does your 4 gas meter have a clip on the back? It is a personal monitor designed to monitor the personal atmosphere around you, not find explosive gases!  You need an explosive gas monitor like the one shown below.  This is a metal oxide based sensor that will detect low levels of flammable gases. It is a good partner for your 4 gas monitor. It will detect many other flammable gas and vapor producing liquids, is inexpensive and very reliable.

   3. Blind spot: Why can you smell the odorant in natural gas at a gas leak but your meter reads zero? There is a blind spot on the catalytic bead sensor in these instruments (your 4 gas) that is blind to around 2% LEL.  The metal oxide sensor mentioned above will detect very low levels of flammable gas and could save your life.

   4. Types of emergencies: There are 7 types of natural gas emergencies: your sops must provide guidance for your officers and members to work within. It is a chief’s responsibility to set the stage for success. Here are the different gas leak scenarios your sop must address:  excavation damage, outdoor odor of gas, inside odor of gas, building explosion, ignited leak, locked building, and transmission line leak.

   5. Laser detectors: Have you seen the new Laser based natural gas detectors? Like the one pictured below, it detects ng from up to 100’ away and works thru most glass. That means you can stay out of the kill box and out of a locked building while determining in your size up the following: where is there a lot of gas, some gas and no gas? This is a huge increase in our efficiency on scene size up as well as a huge increase in ff safety.  Want to know more, go to

   6. Kill box: The area around the building or leak source where you and your crew are likely to get killed if it lights off. A lot like the collapse zone around burning buildings. It is a good thing to have in your sop. The ERG recommends 300’ evacuation zone which maybe a lot in urban and suburban areas.  Don’t park your chiefs car or rigs in the kill box and limit members. A short walk is a good thing, maybe 150 feet.

   7. What does your gas monitor read at 100% LEL? At this level you are in the explosive range, the mix of air and gas is right and just needs an ignition source like a boiler coming on, a thermostat calling for heat, a door bell or light switch arc to ruin your day and maybe your crews lives. Unless you have used a table top explosion chamber with live gas you probably have never seen your instrument go into alarm and probably never seen it at 100% LEL which is the border of the explosive range.  

   So here is the surprise that you probably were never taught. If your 4 gas monitor uses a catalytic bead sensor it shuts off at 100% LEL to keep it from burning out. What does the screen show you? 100%, maybe or it may read OL for over limit or ***.  I strongly recommend you read the directions for your meter to find out and demonstrate it to your members in a table top explosion chamber.

   8. Action level. So you have an instrument that will provide digital readings on the amount of gas (that is explosive gas may I remind you) in the area where you are monitoring. At a certain level, like 10% LEL or maybe 20% LEL the alarm will sound and maybe a good level for your fd action level. What action? Mandatory evacuation of both civilians and firefighters.

   9. Smell gas: Your monitors in alarm, flashing, buzzing trying to get your attention but you don’t smell anything…what is going on?  The ng or propane moved thru the soil and the odorant was scrubbed out….there is odorless ng there and that  is what you meter is trying to tell you. BTW, railroads are shipping non-odorized propane in tank car loads thru your town. Train wreck…. take your gas meter with you.

   10. Cross sensitivities: You go into the home and you get CO readings, they are highest in the attached garage. You ask was the car running, no. What is causing the reading? Many CO sensors are cross sensitive to two other gases….acetylene and hydrogen. In the garage a plumber’s torch was leaking small amounts of this very explosive gas…but your meter showed it as CO! It could have been an over charged lead acid battery. Hydrogen could have been driven off from the acid when the battery was heated. Read the directions for your meter…it is a matter of life and death…YOURS! Don’t forget, it is cross sensitive to acetylene (unstable and explosive gas, really wide flammable range) too!!!

   Two more really important thoughts we don’t have time or space for….Your oxy reading is down to 19.9%….what is going on?….why is this your most important reading…(no not because you need it to breathe)….that is a topic for another issue!  

   Maybe even more important consideration; do you force doors on locked buildings that contain gas? The building is an IEB…im-provised explosive building.  Is it worth the risk? Is there another tactic that makes more sense? Most responsible utilities have a procedure that says for any reading of gas coming from the inside to the outside of a locked building the strategy is to:  immediately withdraw, remotely shut off all electric and gas sources and wait for the building to vent down on its own. There is no safe way to force entry.  If there is no life hazard in the building, why would you put your firefighters lives in danger with no plan B?

   Pls take the time to develop solid sops for your response to the 7 types of ng emergencies you may run into and base them on your local utility procedures.  Your response should be one team one fight not two teams on the field working independently. Don’t forget to read the directions to your explosive gas monitors…you will learn a lot of interesting things that you did not know you did not know.

   (I have a PHMSA grant to conduct propane and natural gas response training at your fire house. Pls feel free to contact me if you are interested. or 845-558-0489)


Blaze Publications, Inc.

Jeff Gargano - Editor
P.O. Box 122
Humboldt, IA 50548
Phone: (515) 604-6400
Fax: (515) 332-1505

News and Advertising: News and advertising deadlines are the 15th of each month for the next month's issue.


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