Smoke Toxin Lessons Learned: Cancer and Respiratory Distress

By Todd Andrews

An incident that took place while on a structure fire on Friday, January 13, 2012, motivated the Springdale (AR) Fire Department to relentlessly identify conditions and practices that were putting our firefighters at higher risk for cancer and to pursue ways to better protect them from these situations and potentially harmful chemical exposures, thereby lowering the firefighter cancer rate.

The Incident

Our department was dispatched to a residential structure fire with confirmed people trapped. The first-in engine company (staffed with two people) arrived to find a single-story residential structure with dark, heavy, dense black smoke showing throughout. The captain on the engine confirmed a working fire. He pulled a line and opened the front door to fight the fire from the outside until more help arrived. A three-person truck, a one-person rescue, a two-person ambulance, a battalion chief, and a second engine staffed by three all arrived together. The ladder truck began a primary search.

The engine captain was holding the fire as the ladder crew made entry. About three feet inside the front door, the crew found the first victim and removed her. As the captain and the medic crew (which “marry up” with the first-in engine and assist with fire attack) were pushing forward, they found the second victim about six feet inside the structure. The captain held the fire while his crew was making the grab. Both victims were alive and survived.

As this time, the captain became entangled in debris. He dropped the nozzle briefly and attempted to move the debris out of his way. A resident’s walker became entangled in his regulator line. (Later, we learned that the resident was a hoarder; there were very narrow paths for access.) One of the walker’s legs caught the captain’s mask and pulled it from his face. He took about six breaths of the superheated, toxic gases. After inhaling the gases, the captain exited the structure to the front yard and proceeded to remove his gear. Later, he said he didn’t realize he had done this. The captain refused medical evaluation, saying that he was fine. However, several hours later, he felt that he needed to be evaluated in the emergency room (ER). He was taken to the ER and was evaluated and released.

The next day, he followed up with the workers’ compensation doctor and was told he could return to work in a couple of weeks. Two days later, he began to have trouble breathing. His family took him to the ER, and he was admitted into the intensive care unit. For several weeks, he was in and out of the hospital. Eventually, he was transferred to the burn center in Little Rock. He came back to work in an administrative role but seemed to be suffering from what appeared to be mini strokes. He had all the classic signs of stroke-slurred speech, facial drooping, short-term memory loss-which were all attributed to his exposure. He was short of breath and had weakness and a facial droop on one side of his body. He eventually took a medical retirement. He is still recovering from long-term effects that include tiring easily.

The Mindset Changer

After this fire, I approached Captain Eric Smith, who since has retired from the department, about learning more about how the department could lower its incidence of exposure to toxins. We began our quest for knowledge. Among our initial efforts were attending a hazmat conference in Houston, Texas; taking a class on metering and the fire scene; and then attending a fire smoke class in Austin, Texas, where we learned much from Jason Krusen, special operations chief for the Columbia (SC) Fire Department, and Rob Schnepp, special operations chief (ret.) for the Alameda (CA) Fire Department; both have been actively involved in the Fire Smoke Coalition and are pioneers in educating the fire service on the threats posed by hydrogen cyanide (HCN). They provided invaluable information and renewed our spark to get something done. We took the information home and began to do our own studies and tests.

We developed the “Fire Ground Monitoring for Post-Fire Incidents” class and presented it to our command staff. Chief Mike Irwin immediately recognized the importance of the class content; he approved it for the membership and arranged to make available the equipment we needed to implement a metering program, including five gas meters with HCN sensors. When the program was presented to the entire department, it opened everyone’s eyes to the hazards in smoke. All could relate because of what happened to our hospitalized captain-it happened to one of our brothers, not to someone else in some other department! This class changed our mindset and how we do business.

Program Components

The class opens with an account of the captain’s experience and proceeds to discuss the immediately dangerous to life or health (IDLH) atmosphere and how it is defined by the National Institute for Occupational Safety and Health (NIOSH). Members must totally understand what IDLH means, the hazards firefighters encounter, and ways to protect against those hazards. We stress cancer awareness and reducing the incidence of cancer (we cannot eliminate cancer, but we can reduce the profile). Our department has had a captain pass away from cancer and several retirees who are fighting the disease. Some other components of the class follow.

Oxygen Drop

HCN and carbon monoxide (CO) are present at every fire. We proved this by metering the venue in which we hold live fire training. We had gone to Huntsville, Arkansas, to conduct burns that illustrated thermal currents and flow paths. We changed the hydrogen sulfide (H2S) sensors on some of our four-gas meters to HCN sensors and tested our five-gas meter. The fire consisted of two uncovered cushions, a few pallets, and some straw-this fire load is not even close to what is in today’s structure fires.

During the burns, we obtained the following readings outside of the burn room:

  • 359 parts per million (ppm) of CO,
  • 28.5 ppm of HCN, and
  • 1.5 ppm of volatile organic compounds (VOCs).
  • We found equally as amazing the drop in oxygen (O2). Its level was 20.7 ppm. For every 0.1 percent drop in O2, 5,000 ppm of “something” took its place! What was that something? No one knows; it could be anything. This is outside, and oxygen was down 0.2 percent. Moreover, that was in the area where there was no smoke; it was the area in which we masked up. I have never seen a drop in O2 outside in a normal atmosphere; it usually occurs in a confined space.

This raises the question: Is it a good practice to mask up at the front door? When we respond to fires, we were taught to get off the rig, pull a line, and mask up at the door. Why? It is what our culture has told us to do. But we need to be aware of the toxins at the door even when there is little to no smoke. CO and HCN are at the door; we are poisoning ourselves for no reason. After fires, how many of us go back to the station and complain of a headache? I have. I didn’t realize I was poisoning my body until recently.

Action: I challenged my crew to do it right and safely. Why not get off the rig, size up where you are going with the line, mask up at the truck, and then pull the line while you are on air?

I received a lot of push-back and guys asking, “Won’t we waste our air?” We went to the drill ground. We went behind our station and set up a 50-foot setback, which is about average in our city. I had them do it their traditional way first, and I timed them. Then I had them do it my way and timed them. The time difference was on average 20 seconds faster when it was done the “new” way.

Think about how we operate. We get off the rig with our self-contained breathing apparatus (SCBA). We put on our helmet and gloves and then we pull the line. We get as close to the front door as we can, and we kneel on the nozzle so that it doesn’t get stolen from us. We take off our helmet and gloves, and we turn on our air bottle, if it isn’t already on. We mask up, pull our hood up, and put on our helmet and then the gloves. In the meantime, we have given the signal to fill the line. We put on and take off our equipment twice, sometimes three times, before we are ready to fight fire. Why not do it once at the rig?

I also counted the number of breaths personnel took. The average firefighter used 16 breaths of air-some more, some less. I asked them, “If you can take 16 breaths of air and not get cancer, would you do it?” Of course, they all said yes. So, why not do it on the fireground?

We all have people in our departments who are fighting cancer from years of not wearing their air at fires, of choking on the smoke from food-on-the-stove calls, of not using diesel exhaust systems, and of not protecting their lungs while investigating fires. Fire investigators are dying from cancers, too. They do not wear respiratory protection while investigating a fire because the fire is out, but the toxins are still there. When investigating or salvaging a fire scene, we drag our feet, shovel, and dig, disturbing the toxins and the micro particles so that they get caught up in the air, and we then breathe them in. When are we going to learn from our past? We all talk about the latest and greatest technology from mapping to our gear. But we forget the most basic thing-we need to protect US!

CO Poisoning

CO is colorless, odorless, and tasteless and is present at all fires and can be at nonfire incidents as well. It is produced from the partial oxidation of carbon-containing compounds. Its IDLH is 1,200 ppm. Its time-weighted average is 35 ppm. Basically, the body likes CO 200 times more than O2 and will accept CO instead of O2. The O2 is replaced with CO at the cell, and tissue hypoxia develops. Signs and symptoms of CO poisoning include headache, nausea, fatigue, confusion, coma, cherry red skin, chest tightness, cardiac arrest, and eventually death.

HCN at CO Calls

We found HCN at bread-and-butter CO calls. HCN is colorless, odorless, and tasteless (some people may experience a taste of bitter almonds or sour nuts when exposed to high levels). HCN’s IDLH is 50 ppm. It is listed as a chemical warfare agent and has been used to kill whales. It is produced at fires from carbon, hydrogen, and the oxidation of methane and ammonia from synthetics’ off-gassing. HCN interferes with the electron transport chain and the energy production in the cell; O2 is present, but it cannot be used. Basically, no matter how much O2 we put into the body, the body will not be able to accept it, and the cells will eventually die. The signs and symptoms include headache, nausea, fatigue, confusion, coma, seizures, the taste of bitter almonds, chest tightness, cardiac arrest, and eventually death. CO and HCN are known as the “Toxic Twins” because the signs and symptoms of CO and HCN poisoning are similar.

What about the “food-on-the-stove” calls? How many times have we gone to these calls with our SCBA on but our mask hanging? We enter the home and find it filled with light white smoke. We go to the stove and find a pan of burnt food. As we take the pot outside, we are choking and coughing from the smoke. We put the positive-pressure ventilation (PPV) fan at the front door and remove the smoke. Think about a few things: (1) All the smoke is hanging in the air. (2) The smoke contains acrolein in addition to CO and HCN. Acrolein’s IDLH is 2 ppm. That choking and tickle in the back of your throat is the acrolein affecting your respiratory system. Now, the fan at the front door is filling the home with CO and HCN (because we know where there is a high level of CO, HCN is also there).

Action: Why are we not using our air on these calls?

(1) Should we be metering at the command post and where the rapid intervention crews stages as well? These are the reading we obtained while at the hood of the second truck in the photo: CO 44ppm and HCN 10.0 ppm. Pump operators are also exposed to the toxins. [Photo courtesy of Captain Eric Smith, Springdale (AR) Fire Department.]
(1) Should we be metering at the command post and where the rapid intervention crews stages as well? These are the reading we obtained while at the hood of the second truck in the photo: CO 44ppm and HCN 10.0 ppm. Pump operators are also exposed to the toxins. [Photo courtesy of Captain Eric Smith, Springdale (AR) Fire Department.]


If you are wondering why we meter for HCN instead of H2S, that is a good question. We meter for H2S for confined space calls, essentially to look for sewer gas. When was the last time you went on a true confined space call? How many structure fires have you been on in the same amount of time? When we call a meter vendor and ask for a four- or five-gas meter, what do we get? We get O2, CO, lower explosive limit, and H2S sensors. Why? Because the Occupational Safety and Health Administration (OSHA) says you need to be able to meter for O2-rich and O2-deficient atmospheres, explosive atmospheres, CO, and other toxic environments. OSHA or NIOSH doesn’t say H2S, but that’s what we get because that’s what everyone thinks they need. We changed our engine meters to HCN sensors instead of H2S sensors and left the truck company meters with H2S sensors. We found that the HCN sensor still picked up H2S. So, if we go on the confined space call and we have a reading on the HCN sensor, is it going to change how we do business? No. We are still going to ventilate and be on a supplied air respirator (SAR). It doesn’t change anything we do.


At the hospital, a smoke-inhalation patient is treated the same as a CO-poisoning patient. If the smoke inhalation is bad enough, the patient survives for only a few weeks. We are told the patient dies from complications of smoke inhalation or chemical pneumonia. What the patient actually died from was HCN poisoning. The HCN closes the cell down so it cannot accept O2. Doctors and hospitals don’t know that HCN is present when CO is present. The fire service treats these patients as the hospital does, except that we also give them hydroxocobalamin (Cyanokit). We have proven that HCN is prevalent in fires. Smoke inhalation patients have been exposed to HCN, and the Cyanokit is the antidote for it. We have used three Cyanokits in the few short years we have had them; two were used on smoke-inhalation patients with CO poisoining, and the treatment was successful.

Through our research, we learned that high levels of CO and HCN are in several places we don’t expect to find them. Several years ago, we had an ice storm, and more than our share of CO-related calls were related to occupants running generators in their garages. We don’t have a portable generator, so we simulated it with our PPV fan, which, by the way, we use at fires and will produce the same results. We also had a certain part of the population turning on their gas stoves and bringing charcoal and gas grills into the home for heat. We found not only CO but also toxic levels of HCN. After the fan ran for just a few minutes, the meter read 1,500 ppm (the sensor was saturated; it could have been higher) of CO and 64 ppm of HCN. When we placed a small charcoal grill in a shed for just a few minutes, we found 101 ppm of CO and 60 ppm of HCN.

Action: Where does command park? What about the rapid intervention crew (RIC)? Should we be metering at the command post and the RIC staging area as well? Let’s see what the meter says. We got these readings while at the hood of the second pickup truck: 44 ppm CO and 10.0 ppm HCN (photo 1). How close does command or the engine sit to the incident? Pump operators are getting exposed to the toxins as well.

Coming Off Air

Where do firefighters come off air? Usually at the front door as they are walking out of the fire structure. Look at the readings with no smoke visible, 249 ppm of CO, 17.5 ppm of HCN, and 0.4 VOC. For all you hazmat gurus out there, if we went to a chlorine leak inside of a building, do we wait to suit up and mask up at the entry door to the building? We all know the answer is no. And when we enter the building and find it is a simple turning of a valve and the leak is stopped, do we exit the building and immediately remove our Level A suit and air? No, we don’t. Then why, if we know there are hazardous materials at every fire (the smoke), do we do it at structure fires? It doesn’t make sense. We need to treat the fire scene as a similar hazmat incident. We need to decon our equipment, clean it, and make it ready for service. When I clean my gear and equipment, I ask myself, Would I let my son wear this gear and use this equipment? Would I expose my wife to the toxins? If the answer is no, then it isn’t really clean.

Action: Treat the fire scene as a hazmat scene. Don’t don your mask close to the structure while entering and exiting. Decon your equipment, clean it, and make it ready for service.

“Cancer in the Fire Service” Scenario

Let’s review the following scenario for some of the hazards that cause firefighters to have a higher incidence of cancer than the general population.

We respond to a residential structure fire. On arrival, we find a single-story wood frame with dark dense smoke coming from the front door. We perform our 360° walk-around as the firefighter pulls the line. Hopefully, we are on air before we reach the front door. We make entry and find a small room-and-contents fire. We make a quick knockdown and start to overhaul. The temperature outside is 80°F; humidity is 80 percent. We are sweating. What happens when we sweat? Our pores open up, and we absorb the toxins from the smoke into our bodies. Our gear is designed for thermal, not smoke, protection. Our gear has absorbed the toxins into it as well. We “clean” up after the fire and return to our station. Maybe we wash our gear or maybe we don’t. Maybe we take a shower and change clothes, maybe not. Let’s say we don’t do either. We don’t have another call for the rest of the shift. We go to bed without showering and put our bedding away. We come back to work the next shift and put our dirty gear on the rig. We have several automatic alarms that turn out to be false, but we get dressed out for every one. It is another hot day, and we are sweating, Because we didn’t wash our gear, what is happening? We are absorbing the toxins from the previous fire into our bodies through our pores. Just because we hung our gear doesn’t mean it is clean and free of toxins.

High-Incidence Cancers for Firefighters

Thyroid cancer. Among the types of cancers most prevalent among firefighters is thyroid. Our hoods are one of the weakest protective parts of our gear. We sweat and absorb the toxins through the hood and into our lymph nodes and thyroid. We really need to make sure our hoods are clean. Maybe we should have two so that when one is dirty we have a clean one ready to go.

Testicular cancer. Another high-incidence firefighter cancer is testicular. Think about where we place our dirty hood when we stage our gear. If you’re like me, you place it in the groin area between your boots. If our hood is dirty, the contaminants leach into our groin area, causing testicular cancer.

Lung and brain cancers. Where do you stage your gear? My gear was staged next to the exhaust of our engine because the compartment I keep it in was right there. When the engine started, my gear was filled with toxins. I have since moved my gear staging area.

Do we get these cancers because we are tough firefighters and don’t need to use our air, we don’t or won’t mask up before the door, or we don’t take respiratory protection after the fire? It is for all these reasons and more. The incidence of some of these cancers can be reduced by simply cleaning our gear. Our gear can off-gas and release toxins minutes, hours, and even days after a fire. Captain Smith placed his gear in a trash bag after a training burn. Thirty minutes later, he obtained these readings: O2, 20.9; CO, 19 ppm; HCN, 10.0 ppm; and VOC 2.0 ppm.

We have developed a program where we meter after the fire is out, no smoke is visible, and the fire is “cold.” We enter on air and meter for O2, LEL, CO, and HCN. If we get a CO reading of 25 ppm or higher, we are on air. If the HCN level is 2 ppm or higher, we are on air. If the levels are lower, we switch to an air-purifying respirator (APR) with P-100 filters. It filters out several contaminants, but the most important group is the particulates in the air. The APR high-efficiency particulate arresting (HEPA) filter prevents contamination of the respiratory system. The firefighters like the APRs because they can be shed once the contaminant levels in the environment have gone down; they can shed the pack and assist with light overhaul, investigations, and tool collection. Anyone entering the structure is required to wear them. The SCBA provides the best possible respiratory protection, of course; but it doesn’t always work for us. The APR is not perfect, but it works for us in the high heat and high humidity in our area. It helps us do our job safer.

Action: Make sure to clean your hoods as part of your gear. Your hood is in contact with your lymph nodes and thyroid, sites of high cancer incidence for firefighters. When breaking down your gear, don’t unsnap the liner and pull it apart. This causes the toxins to become airborne. Should we protect our airway with a simple N-95 mask or the APR when doing this? Should we be soaking our gear for a couple of hours in warm water and mild detergent before putting it in the extractor? The next time you wash your gear after a fire and don’t presoak it, put the gear in a 55-gallon trash can with some warm water and mild detergent. If the gear turns black, it is still contaminated.

Dirty gear isn’t as appealing as it used to be. “Roasting the rookies” shouldn’t be about getting their gear loaded with toxins from fires. We are putting our rookies’ lives in danger.

Are there any success stories? Yes. Since we have implemented the program and taught it around our area, the local hospitals have stocked the Cyanokits. We were the first EMS-based fire department in the state of Arkansas to have the kits on our medic units. Our medical director, Dr. Mark Rucker, is very supportive and helped us write the local and statewide protocols. Two local firefighters were given the Cyanokit. One was walking through a living room of a structure fire when the floor collapsed. He was rescued quickly and given a kit. He has had no complications. Another firefighter was fighting a trailer fire. His SCBA malfunctioned, and he pulled off his mask when air stopped flowing. He took several breaths of the gases and was immedietly flown to a hospital that had the Cyanokit. The kit was administered; the firefighter is still recovering and is expected to make a full recovery.

Be an advocate for you and your crews. If one of your crew takes even one breath of the gases, you need to have him checked medically and given the Cyanokit. Develop training programs locally. The doctors don’t realize what we are up against. Change your old habits, and form new ones. Tradition is what we are about, but it shouldn’t be about dying, Don’t love your job to death. Do your own research in your own department. I challenge you to go to the drill ground and see for yourself. The toxins are present even if there is no smoke. Don’t take my word for it. You will be absolutely amazed with the results.

Todd Andrews, a 29-year veteran of the fire service, is a captain and acting battalion chief with the Springdale (AR) Fire Department, where he has been a member since 2002 and is assigned to Station 3, the hazmat station. He is also the assistant chief of the Johnson (AR) Fire Department, a combination department. Previously, he was chief of the South Byron (NY) Volunteer Fire Company. He is enrolled in the Management Officer class at the National Fire Academy.

Dangers of Fire Smoke Exposure
Toxicology of Smoke Inhalation
Cyanide: Fire Smoke’s Other “Toxic Twin”

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