The Danger of Smoke

We often picture barns as wooden structures inside and out—the kinds of barns seen on century-old farms and older boarding stables.  Where once the items in a barn were produced from “natural” materials such as leather, iron, cotton, wool, and rubber, now we rely so heavily on plastics that we have nearly ceased to be aware of these potential hazards and the toxic byproducts that may be  released or formed in a fire.

We have more plastic and petroleum-based products in our barns nowadays than we realize, and in a fire the gases produced by some plastic products can be highly toxic. If you still have that picture of a wooden barn in your mind, look around your current barn. You probably have plastic feed tubs, plastic water buckets, nylon hay bags, nylon halters and lead ropes, nylon saddle bags, plastic stall signs, horse ball toys, grooming tools, and plastic (bless the person who invented these) manure forks. And don’t forget the plastics used in packaging medications and supplements, feed bag liners, bagged wood shavings, and even plastic baler twine.

With that in mind, I’d like to start this section with an excerpt from a somewhat scholarly article I wrote about 20 years ago:

“The greatest danger to life in fires are the gases and smoke produced by the burning materials. Smoke has a visible component and an invisible component. The visible component, particles of matter in varying sizes, is dangerous because it cuts down or completely blocks vision, slowing or stopping the evacuation of occupants from a burning structure.

The gaseous component is dangerous because it contains substances that can kill. Carbon monoxide (CO) and hydrogen cyanide (HCN) are the two most common fire gas constituents. It is generally well-known that carbon monoxide is lethal and is present in all fires. In the bloodstream, where carbon monoxide displaces oxygen, the presence of carboxyhemoglobin (COHb) in levels equal to 50% or more of total hemoglobin is considered lethal. A check of  the COHb level in a victim’s blood is usually the first step in determining the cause of death in a fire. Hydrogen cyanide appears to add to the toxic effect of carbon monoxide in interfering with oxygen transport and metabolism. Hydrogen cyanide is also commonly found by direct analysis at autopsy.

The first realization that toxic combustion products previously unknown might imperil lives came with the Cleveland Clinic fire on May 15, 1929. In that fire, the newly-developed product, nitrocellulose x-ray film, played a major role. No one is positive how the fire started in the hospital’s basement where the x-ray films were stored, but when firefighters arrived, poisonous yellow gas fumes given off by the burning films were filling the clinic building. People inside were quickly overcome, and when windows burst, people on the street were also overcome by the toxic smoke. Firefighters attempting to enter the building were driven back by the gas fumes. Firefighters with hose lines literally cut through the smoke to keep flames away from their fellow firefighters who were trying to resuscitate victims. The gas from the films did not claim all its victims immediately; some people walked out of the building in good condition only to die hours or even days later.”

Carbon monoxide is often the largest component of smoke.  It’s a colorless, odorless toxic gas that is a product of incomplete combustion.  When carbon monoxide is breathed in, it takes the place of oxygen at a rate of 300 to 1 and actually suffocates its victim.  Even at low levels, over a period of time, it can be dangerous.

My husband and I experienced one of the earliest signs of carbon monoxide poisoning one night while driving home in my husband’s fairly new 1976 Cadillac.  We were on a perfectly smooth road  when my husband gave a groan of disgust and said we had a flat tire. I hadn’t felt any change in the car’s behavior. We both got out and saw that all the tires were fine. I offered to drive, and got behind the wheel. Within a couple of minutes, I felt the car lurching as if a tire was flat!  By that time we were at our driveway, so I parked the “crippled” car in the garage and once more we checked the tires and found them to be fully inflated.  We decided we couldn’t both be crazy, so the next morning my husband took the car in to be checked (he drove with all the windows down) and sure enough, an inspection found that exhaust fumes were seeping into the passenger compartment on the driver’s side!  That’s why each of  us had become disoriented when we drove, and through the power of suggestion, why I was also sure a tire was flat.

In addition to disorientation, such as we experienced, other first stages of carbon monoxide poisoning can be flu-like symptoms (dizziness, weakness, nausea, vomiting), a headache or throbbing at the temples, some loss of muscle control and an increase in pulse and respiration.

In the middle stages, the victim will be conscious but very confused and may not be able to move due to muscle weakness.

In the final stages of carbon monoxide poisoning blood pressure falls, muscular control is lost, reflexes are dulled, and there may be convulsions. Then breathing grows shallower until it finally stops.

Now, imagine yourself or another person or an animal in your barn suffering from these symptoms when no fire is present, but perhaps, you’re operating a tractor in the barn. If you notice a person or animal who is behaving oddly, or you begin to have symptoms  yourself, shut the equipment down and get everyone involved out to fresh air immediately.

Carbon monoxide is the part of smoke you can’t see. The part of smoke you can see has three main effects on your body (and an animal’s body): eye irritation; narcosis (loss of consciousness); and respiratory damage.

Smoke reduces visibility, which slows you down, making your evacuation take longer, exposing you and your animal to the toxic products of smoke for a longer period of time.  Smoke causes nerve endings in the cornea to react, causing pain, blinking, and tearing.  Shutting your eyes to ease these effects definitely impairs the speed of escape.

Narcosis refers mainly to toxic gases that can result in central nervous system depression with loss of conciousness and finally, death.  Depending upon the concentration of such irritant gases in the smoke, your evacuation efforts can be impeded by the early stages of narcosis which result in disorientation.  If either you or the animal(s) you are attempting to evacuate become disoriented, the chances of  your successful evacuation are poor.

Lung irritation produces coughing and bronchial constriction with resulting tissue inflammation and damage.  Death often follows exposure to high concentrations of irritant gases, usually after 6 to 48 hours, as happened in the Cleveland Clinic tragedy. One reason humans are so prone to lung irritation is that we have a tendency to be mouth breathers, especially in stressful situations like a fire.  By not breathing through our noses, our bodies can’t take advantage of the cleaning ability of our nasal passages.  Coughing, as a protective mechanism, also slows down our escape because it’s extremely difficult to lead an animal and have a coughing fit at the same time, even on a clear day when the sun’s shining.

All of this information points to one factor: time is of the essence when it comes to evacuation, not just to escape the heat and flames but to escape the equally dangerous smoke.