Two Letters Re: Gas Masks, Fire, and Chlorine Gas

Just something I would really like to beat to death, and that’s Chlorine, Fires and Gas masks. I just keep getting this really creepy feeling that there are a lot of folks out there that aren’t clued in on the limitations of gas masks and may kill themselves.
First:, grass fires, forest fires and house fires.
A gas mask will keep you from choking on the fumes and stop your eyes from watering but it will kill you!
The mask will stop the particulate matter that irritates your eyes, throat and lungs but it will not make oxygen where there is none, like in the fires described above, and you will suffocate! You’ll pass out
Second, chlorine is a particularly nasty product. Most of the normal ABC, NBC, and biowarfare filters will trap a lot of nasty stuff in the activated charcoal granules in the filter. BUT MOST WILL NOT STOP CHLORINE! Chlorine requires a special filter. If you have masks and you anticipate Chlorine then get the right filter!
Okay, I feel better. It was this part from today’s post that triggered me: “Unfortunately, the chlorine gas saturation level in the area was too high and most vehicles would not start. Many families perished in their cars. Gas masks are great idea if you have to walk out.” If they had tried to walk out without a chlorine filter on their mask, they would have died anyway. I’ve seen Chlorine deaths and it’s not pretty. Thanks for letting me vent. Best Regards, – The Army Aviator

JWR Replies: Thanks for mentioning the importance of gas mask filter selection! You are right that most “typical” masks sold to civilians do not protect against chlorine. For example, the ubiquitous “green ring” cheek filters for U.S. M17 series masks do not protect against chlorine. However, the current NATO issue C2A1 filter canisters (which are standard issue for M40 series masks) do protect against chlorine. SurvivalBlog readers that live near train tracks or a chemical plant should do their homework before they buy.
And, as you pointed out, both the gas concentration level and the available oxygen level are both crucial issues, regardless of the filter used. How much oxygen? OSHA defines a “safe” oxygen level for mine workers as 19.5%, or higher. With a web search, I found the following on a forestry web site: “A fire consumes the oxygen essential to human survival. During a fire, the normal level of oxygen in the air (about 21%) drops rapidly. If the level drops below 17%, clear thinking and muscle control become difficult. When the oxygen level in the air drops between 6% and 10%, breathing stops, and after four to six minutes without oxygen, brain death occurs.”]


I have worked US Air Force NBC for several years and civilian law enforcement. I have read with interest the information regarding hazardous materials spills by the SurvivalBlog reader in North Carolina. I was concerned about the advice about using gas masks to protect yourself and family. Toxic Industrial Materials are referred to as TIMs. The common gas masks the many individuals have (Israeli, US surplus M-17s, MCU 2A/P) are only filters. They will stop many chemicals, but they will not provide oxygen. I know that this is understood by most readers but if this prevents one person from going into a cloud of methyl-ethyl-kill-you then it was worth posting. If there is enough chlorine concentration in the air to prevent a car from starting then a mask will not protect you. I do not remember the chemical but I saw a video of two US Army Chemical Corps troops checking what appeared to be a large propane tank in Iraq or Afghanistan.
This was a real incident but not covered by the media. It was being videoed by another troop. They had their sampling equipment at the ready. They opened the tank and within seconds the were on the ground and died. Was it some kind of super warfare agent? No, it was an industrial chemical. (The name escapes me.)
If you are dealing with an unknown TIM, you need a self contained breathing apparatus like firefighters wear. Otherwise, take the safe room approach and seal your self in. Hopefully they will get the leak sealed off and it will dissipate before you run out of air. A HEPA filter will not safely ventilate a safe room when TIMs are involved. A mask and a HEPA filter will protect you from bio agents and the charcoal elements will protect from warfare chemicals but TIMS, depending on what they are can be a different story. The Department of transportation puts out
the hazmat guide, usually yellow that describes most of the truck placards and different chemicals. (Even war agents.) The guide has a cross reference including what is needed to protect you. It has other info as well. My buddy who also works military NBC plays a game on the road with his kids. They each have a copy and race to see who can figure out what the placarded trucks are carrying first. I haven’t done that with my kids yet. Regards, – Nightshift in Mississippi

One Comment

  1. I know this is an older post, but I would like to know if there is a shelf life to gas masks and their filters. I have some Israeli civilian masks and filters that are about 20 years old.

Comments are closed.