Hey there everyone, I'm sorry that I haven't posted in a while, but I've been pretty busy taking some college courses. I've definetly been doing a lot of writiing. My free time is pretty limited. At the request of some of my fire buddies, I'm going to post some of my college papers as posts. This might be interesting to some of you, as most are about fire department related stuff.

Heres an article/paper about the Human Body and Smoke inhalation:

The Human Body’s Response to Fire Gases, Heat, and Visible Smoke

There are many toxic gases which are produced as a byproduct of combustion. The toxic gas cocktail that is produced is dependent on the fuel being burned. Historically, structures were built using some combination of wood, masonry, and steel. After World War II, new manufacturing processes enabled the plastic industry to mold and form plastics into building materials. (Packaging Today, n.d.) The construction industry embraced these new materials because they were lighter, in some cases stronger, and had a more consistent dimensions and stability. However a significant problem with plastics is that when on fire, they produce a greater number of toxic gases and thicker smoke than traditional construction materials. Plastics combined with the high heat output of traditional construction materials produce modern fires which are more deadly because of their higher heat, their toxic gases, and their reduced visibility. This paper will analyze the effects of a modern structure fire on the human body.
In his work on fire gas production, Dr. Vytenis Babrauskas identified 20 lethal gases that, dependant on the fuel package, could be encountered as byproducts of a structure fire. Further he notes that “carbon monoxide accounts for about ½ of fire toxicity problem” (Babrauskas, 1997). In addition to the abundance of carbon monoxide during structure fires, highly toxic phosgene, hydrogen cyanide, sulfur dioxide, and acrolein are all present. Each of these is considered lethal in exposures of less than 1000 parts per million to victims exposed for 5 minutes or more. The human body can be attacked by these toxic gases through means of asphyxiation, pulmonary irritation, and toxicity. oxygen or an increase of carbon monoxide in the blood” (Webster's Dictionary, 1996). The propensity of carbon monoxide, which is an asphyxiant, to attach itself to the hemoglobin of the red bloods cells is 250 times more than that of oxygen. In doing so, the red blood cells cannot carry oxygen to the body, thus causing the victim to become hypoxic. Depending on the degree and duration of the exposure to carbon monoxide, the victim’s respiratory system can no longer supply the victim’s body with enough oxygen for normal functioning and will slip into unconsciousness and eventually death through asphyxiation.
In the 20th edition of the Fire Protection Handbook, Richard Gann and Nelson Bryner (2008) outline the two primary types of irritants: sensory and pulmonary (p. 6-16). Polyvinyl chloride (PVC) is widely used in modern construction as plumbing piping, electrical conduit, accent trim, and vinyl siding. One byproduct of fires involving PVC products is halogen chloride. Halogen chloride is a both a strong sensory irritant in addition to being a pulmonary irritant. Sensory irritants attack the eyes and upper respiratory airway. The body’s reaction to the pain in the eyes includes tear production and involuntary eye blinking. The irritation to the upper respiratory tract causes the mucus membranes in the throat and nasal passages to create excessive mucus to remove the irritant from the body. This flushing of the excess mucus causes involuntary coughing in the victim.
Asphxiants and irritants are the most prevalent types of toxicants found in fires. However, other toxicants can be found in fire gasses. The type and number of these toxicants is dependent on the type of fuel being burned. The breakdown of the fuel and the chemical changes associated with it create an endless possibility of toxicants. Because of the unlimited number of toxicants possible and significant variables presented by changes in exposure time, there is limited data available regarding the effect on human body’s reaction to toxicants. Most information regarding toxicity is extrapolated from lethality and incapacitation times in testing with rats. Using toxic gas models, the lethal quantities necessary for fatality or incapacitation in rats are multiplied by varying numeric factors to estimate effects on humans (Gann & Bryner, 2008).
In addition to toxicity, another byproduct of a modern structure fire is heat. According to Gann and Bryner (2008), “Heat produced from a fire present significant physical danger to humans in three basic ways: burns to the skin, hyperthermia or heat stroke, and respiratory tract burns” (p.6-26). In a fire event, the primary means of heat energy transfer to the victim is radiant heat. Radiant heat energy can cause damage to the body if the intensity and duration exceeds the body’s natural cooling defenses. According to Gann and Bryner, the human body’s “tenability limit for exposure of skin to radiant heat is approximately 2.5kW/m2, below which exposure can be tolerated for 30 minutes or longer without significant consequences” (p.6-26).
Another important means of heat transfer is convective heat energy. Convective heat energy attacks the human body by exposure to superheated gases. The body’s natural defenses are unable to cool itself and the victim suffers environmentally induced hyperthermia. During hyperthermia, the body’s natural cooling mechanisms of perspiration and blood flow continue to attempt to self regulate the body’s temperature. However, when the body reaches 106°F, the body’s self regulation system shuts down, causing heat stroke which is a critical medical emergency (Helman & Habal, 2009). In order to combat heat stroke, the body must be rapidly cooled by external means before permanent damage and/or death occur
Burns to the respiratory tract occur when a victim inhales superheated toxic fire gases, thus causing injury and toxic exposure to the victim’s lungs. Through the process of normal inhalation and exhalation, the alveoli remove carbon dioxide from the blood and replace it with oxygen to be carried thoughout the body. In their work on smoke inhalation, Keith Lafferty and Harry Goett noted “Inhalation injury from smoke and the noxious products of combustion in fires may account for as many as 60-80% of fire-related deaths in the United States” (Lafftery & Goett, 2010). The body’s natural defense systems fight to protect the injured organs of the respiratory tract. Often fluid accumulation, in the form of swelling of the lungs, further complicates the transfer of oxygen to the already injured alveoli. This process interferes with the victim’s ability to breathe.
The skin is the largest organ of the body and is a primary means of defense from external attack. All three types of heat energy transfer attack the skin’s surface. Depending on the intensity and duration of the exposure, skin may be damaged by: first degree burns which involve only the outer layer of skin and cause pain, redness, and swelling; second degree burns which involve both outer and underlying skin and blistering; third degree burns which extend into the deeper layers of tissues and they additionally present white or blackened skin that may be numb (Penn Medicine, 2010).
While conductive heat energy transfer in a live victim is possible, the duration of extended exposure to a direct flame is rare. In large scale exposures, such as an explosion or ignition of an engulfing fire, the victim may or may not be able to escape before being overcome. On small scale exposures, victims instinctively move their entire body or the exposed portion of the body away from the heat source.
Visible smoke is an airborne accumulation of particulate carbon and other products produced by incomplete combustion. The thickness of the smoke is highly dependent on the fuel being burned, the efficiency of the fire in consuming the fuel, and the ventilation characteristics of the fire compartment. Gann and Bryner (2008), state that “[o]bscuration of vision due to smoke is related to its concentration and is usually expressed as optical density per meter” (p. 6-27). As this optical density increases one’s ability to see clearly decreases. As such, the human eye incrementally loses the ability to clearly identify light signals and the ability to differentiate contrasting colors, such as exit signs and corridors, becomes compromised.

References
Babrauskas, V. (1997). Toxicity for the primary gases found in fires. Retrieved October 15, 2010, from http://www.doctorfire.com/toxicity.html
Gann, R., & Bryner, N. (2008). Combustion products and their safety effects on life safety. In A. E. Cote, Fire Protection Handbook 20th ed. Section 6. (p. 6.16). Quincy, Massachusetts: National Fire Protection Association.
Helman, R. S., & Habal, R. (2009, September 18). Heat Stroke. Retrieved October 17, 2010, from http://emedicine.medscape.com/article/166320-overview
Lafftery, K., & Goett, H. (2010, June 30). Smoke Inhalation. Retrieved October 15, 2010, from http://emedicine.medscape.com/article/771194-overview
Packaging Today. (n.d.). A Plastics Explosion - Polyethylene, Polypropylene, and Others. Retrieved October 15, 2010, from http://www.packagingtoday.com
Penn Medicine. (2010, January 13). Burns. Retrieved October 17, 2010, from http://www.pennmedicine.org/encyclopedia/em_DisplayArticle.aspx?gcid=000030&ptid=1
Webster's Dictionary. (1996). Webster's Newly Revised Dictionary. Boston New York: Houghton Mifflin Company.