Respiratory and inhalation hazards on fire scenes

Respiratory and inhalation hazards on fire scenes

By Alan Perry

August 30, 2014

Smoke is a complex and dangerous by-product of combustion presenting many dangers to firefighters and building occupants during and after a fire event. The most obvious concern is during the fire where super-heated gases loaded with toxins and asphyxiants can enter the airway & lungs causing immediate acute respiratory problems. These are well understood as are the dangers of post-fire exposure to carbon monoxide and cyanide, but this is only the tip of the iceberg so-to-speak. I would like my comrades to consider a fuller disclosure about the dangers of post fire exposure to the other asphyxiants, irritants, chemicals and particulates that are also present during overhaul, investigation and recovery stages that we do not routinely monitor. I believe many are lulled into a false sense of security by the lack of information about the harm caused by, and technology for measuring these harmful agents. Consider the typical fire where the scene is declared safe for removal of SCBA because of a low level of carbon monoxide. What other agents may be present? What are the compounded effects of multiple agents’ short term and long term? If a firefighter or citizen has detectable levels of CO in their bloodstream and/or evidence of cyanide exposure, what other agents have they also been exposed to? The by-products of combustion are not always present in a recognizable form such as smoke; they can linger for hours or days in the debris and residue at a fire scene and on tools and turnout gear. Just because you can’t see it does not mean it is not there.

The compounds present in the post-fire environment include asphyxiants, irritants, complex compounds and particulates. Most of these are present in all fires; the exact composition will depend on what is burned and how it burns. The transition in home construction and furnishings, as well as items kept in storage areas such as garages and sheds can yield a very wide variety of harmful agents when burned. This makes it virtually impossible to predict exactly what, or how much, is present in any given fire event. As I stated earlier, most every firefighter is aware of the dangers associated with CO and cyanide, we talk about these a lot, and we have tools to measure and treat the effects of these. Now let’s look at the “other stuff”

        

Asphyxiants- these compounds interfere with transport of oxygen in the blood stream and use of oxygen by target tissues or displace oxygen, causing hypoxia.

            Substance                                            Source                                                 effects begin

·         Carbon Monoxide (CO)                     incomplete oxidation of organic fuels

·         Hydrogen Cyanide (HCN)                 organic fuels containing carbon & nitrogen                                       <130ppm

·         Carbon Dioxide (CO2)                       organic fuels

·         Oxygen deficient atmospheres

Irritant gases- these compounds irritate and in many cases damage the airways and lung tissues reducing their ability to function and causing pulmonary edema and introducing toxins.

·         Hydrogen chloride (HCL)                  plastics, polymers, PVC                                                                           35 ppm

·         Hydrogen bromide (HBr)                   synthetic polymers, flame retardants                                                      5   ppm

·         Hydrogen fluoride (HF)                      fluorinated synthetic polymers                                                              0.5 ppm

·         Sulfur dioxide (SO₂)                            fossil fuels, rubber, tires                                                                          0.4 ppm

·         Nitrogen Oxides (NO_x)                        any combustion in ambient air                                                            20  ppm

·         Phosphorous pentoxide (P₂O₅)          electrical components, flame retardants                                                 n/a

·         Acrolein                                                 wood, cotton, paper                                                                               0.5 ppm

·         Formaldehyde                                      wood, cotton, polymers, plastics                                                          0.1 ppm

·         Ammonia (NH₃)                                  wood, coal, paper, household waste                                                    50 ppm

·         Chlorine                                                 plastics, polymers, synthetic rubber                                                     1 ppm

·         Phosgene (COCL₂)                              chlorinated compounds, plastics, polymers                                       3 ppm

Complex molecules- long carbon-chain and carbon ring compounds. These compounds can have acute effects and are known carcinogens & mutagens, in addition to their irritant and toxic effects. Several have delayed onset of symptoms.

·         Polycyclic aromatic hydrocarbons (PAHs)  organic materials                                                                              n/a

·         Dioxins/Dibenzofurans                      PVC, PCB, plastics                                                                                       n/a

·         Isocyanates                                          polyurethane foam & plastics                                                                   1 ppm

·         Perfluoroisobutylene (PFIB)              PTFE, fluorine containing polymers                                                        n/a

·         Particulate matter                               

The sources of these materials are not unusual, therefore nearly all of these agents can be found in varying concentrations during and after a fire event. The interactions and effects on the human body are still largely unexplored but clearly are likely to affect the health of those exposed. The effects may be delayed for hours, weeks or years and the cumulative effects will be even harder to predict.

Firefighting causes a great deal of stress on the body from the combined effects of hyperthermia and physical stress causing profound changes in physiological function, particularly with the circulatory system. Firefighters experience coagulopathy for up to two hours after a fire event, in this state the blood does not clot properly even when properly hydrated. When you are exposed to smoke, injuring lung tissue and poisoning the circulatory system with toxins, it is easy to see why we suffer cardiovascular problems and death.

Something to think about before you pull your face piece off next time.

References:

Wakefield, J.C., A Toxicological Review of the Products of Combustion, Health Protection Agency, 2010

Demling, Robert H., Smoke Inhalation Lung Injury: An Update, Harvard Medical School, Burn Trauma Center, 2008

Heart Attacks

Heart attacks

Cardiac events are a prime source of injury and death in emergency services. They are attributable to levels of physical fitness and dehydration primarily. Physical fitness is a no-brainer provided you attain it in a responsible manner. A good workout routine will promote flexibility, endurance and strength equally and not push the body to exhaustion or failure. We self-ingest caffeine, energy drinks and protein supplements in our efforts to remain awake and enhance our physical and mental performance; at what cost? Caffeine is a diuretic; it virtually guarantees a state of dehydration. Both caffeine and other substances present in energy drinks override the body’s protective mechanisms and can/do push your cardiovascular system beyond its ability, occasionally causing chest pain, arrhythmia or stroke. Protein supplements require proper hydration to prevent kidney damage, in a firefighting or any high heat, high stress situation you can easily cause yourself permanent damage, or even death when using these supplements while on duty if you are not careful. AP

Hearing loss....what did you say?

Hearing Loss...what did you say?

by Alan Perry

October 1, 2014

Why do fire trucks have headsets? Is it so you can talk to each other? Communicate with the dispatcher? do they just look cool? A federal Q-siren produces 123 decibels of sound pressure, according to most sources this is enough to cause immediate pain and permanent hearing loss within seconds, add a 140 decibel air horn too that mix and you create a dangerous situation for both your crew, and the general public, without substantial hearing protection like that provided by a properly sized and maintained headset. You have hearing protection on the engine. That is good, what about the medic and the other response vehicles? Does the guy in the convertible trapped in traffic in front of you have any protection? Does the small child playing in their yard? 

Warning devices are only one concern, there are many others; chain saws, power tools, PPV fans and pump panels are all dangerous too. Hearing loss occurs from brief exposure to intense sound pressure as well as routine exposure to levels as low as 90 decibels, which is the ambient sound pressure inside an engine or medic just driving down the road normally. Does your Department have a hearing protection policy? Are earplugs available when not in your apparatus? Do all of your response vehicles have headsets like those on the engine and ladder? 

Like respiratory and cardiac injuries we sustain as a result of complacency with the use of other PPE, hearing loss is no different. We injure ourselves in all these ways due to our culture of peer-pressure, not wanting to look weak, and because of lack of enforcement for existing policies and State and Federal regulations. There are two possible explanations for allowing yourself to be injured in these ways; one is ignorance which you can no longer claim at this point, the other is stupidity which I am not equipped to correct for you. 

Don't wait for the hearing loss to occur, if your employer is still able to justify not providing the necessary protection you should provide your own, sustaining a hearing injury or any other injury is never worth making a point. Tradition can be hard to change as can be an organizational culture to presents roadblocks to protecting employee health. New data and studies of the various health effects associated with emergency services are readily available to help organizations and individuals create safer and healthier workplaces, it will be an ever evolving process. We work in a risky profession already, we should remove those risks that we can reasonably control.

Be Safe,
Alan

Death by Overhaul

Respiratory and inhalation hazards on fire scenes

By Alan Perry

August 30, 2014

Smoke is a complex and dangerous by-product of combustion presenting multiple dangers to firefighters and building occupants during and after a fire event. The most obvious concern is during the fire; where super-heated gases loaded with toxins and asphyxiants can enter the airway & lungs, causing acute respiratory problems. These threats are well understood, as are the dangers of post-fire exposure to carbon monoxide and cyanide, but this is only the tip of the iceberg. I would like my comrades to consider a fuller disclosure about the dangers of post fire exposure.There are other asphyxiants, irritants, chemicals and particulates that are also present during overhaul, investigation and recovery stages, that we do not routinely monitor, but are injuring and killing us due to our complacency. I believe many are lulled into a false sense of security by the lack of information about the harm caused by, and technology for measuring these harmful agents. Consider the typical fire where the scene is declared safe for removal of SCBA based on a low level of carbon monoxide alone. What other agents may be present that have not been tested for, and what are the compounded effects of multiple agents’ short term and long term? If a firefighter or citizen has detectable levels of CO and/or cyanide in their blood, what other agents have they been exposed to? The by-products of combustion are not always present in a recognizable form such as smoke; they can linger for hours or days in the debris and residue at a fire scene and on tools and turnout gear. Just because you can’t see it does not mean it is not there.

The compounds present in the post-fire environment include asphyxiants, irritants, complex compounds and particulates. Most of these are present in all fires; the exact composition will depend on what is burned and how it burns. The transition in home construction and furnishings materials, as well as items kept in storage areas such as garages and sheds can yield a very wide variety of harmful agents when burned. This makes it virtually impossible to predict exactly what, or how much, is present in any given fire event. As I stated earlier, most every firefighter is aware of the dangers associated with CO and cyanide, we talk about these a lot, and we have tools to measure and treat the effects of these. Now let’s look at the “other stuff” that is injuring and killing us.

Asphyxiants- these compounds interfere with transport of oxygen in the blood stream and use of oxygen by target tissues or displace oxygen, causing hypoxia.

            Substance                                 Source                                       effects begin

·       Carbon Monoxide (CO)                   incomplete oxidation of organic fuels

·       Hydrogen Cyanide (HCN)               organic fuels containing carbon & nitrogen                  <130ppm

·       Carbon Dioxide (CO2)                     organic fuels

·       Oxygen deficient atmospheres

Irritant gases- these compounds irritate and in many cases damage the airways and lung tissues reducing their ability to function and causing pulmonary edema and introducing toxins which affect the nervous system, the heart and other organs.

·       Hydrogen chloride (HCL)                plastics, polymers, PVC                                               35 ppm

·       Hydrogen bromide (HBr)                synthetic polymers, flame retardants                          5   ppm

·       Hydrogen fluoride (HF)                   fluorinated synthetic polymers                                    0.5 ppm

·       Sulfur dioxide (SO₂)                        fossil fuels, rubber, tires                                                  0.4 ppm

·       Nitrogen Oxides (NO_x)                    any combustion in ambient air                                       20  ppm

·       Phosphorous pentoxide (P₂O₅)        electrical components, flame retardants                      n/a

·       Acrolein                                                          wood, cotton, paper                                            0.5 ppm

·       Formaldehyde                                  wood, cotton, polymers, plastics                                    0.1 ppm

·       Ammonia (NH₃)                               wood, coal, paper, household waste                             50 ppm

·       Chlorine                                                          plastics, polymers, synthetic rubber                 1 ppm

·       Phosgene (COCL₂)                           chlorinated compounds, plastics, polymers                3 ppm

Complex molecules- long carbon-chain and carbon ring compounds. These compounds can have acute effects and are known carcinogens & mutagens, in addition to their irritant and toxic effects. Several have delayed onset of symptoms.

·       Polycyclic aromatic hydrocarbons (PAHs)  organic materials                                            n/a

·       Dioxins/Dibenzofurans                    PVC, PCB, plastics                                                       n/a

·       Isocyanates                                       polyurethane foam & plastics                                      1 ppm

·       Perfluoroisobutylene (PFIB)           PTFE, fluorine containing polymers                           n/a

·       Particulate matter                           

None of the sources of these materials are unusual, therefore nearly all of these agents can be found in varying concentrations during and after any fire event. The interactions and effects on the human body are still largely unexplored but clearly are likely to affect the health of those exposed. The effects may be delayed for hours, weeks or years and the cumulative effects will be even harder to predict. With this information we can no longer be passive and complacent with respiratory protection. We know the environment during and after a fire is dangerous, we have been given the best possible equipment to protect ourselves, now we must be accountable for our part in preserving our health for our own sake as well as those we love and work with. It's not just the PPE, we have to acknowledge that how we use it, clean it, store it, inspect and maintain it is not someone else's problem, it will surely be ours if we fail to recognize and address the risk.

Something to think about before you pull your face piece off next time.

References:

Wakefield, J.C., A Toxicological Review of the Products of Combustion, Health Protection Agency, 2010

Demling, Robert H., Smoke Inhalation Lung Injury: An Update, Harvard Medical School, Burn Trauma Center, 2008