Online Exclusive

Cyanide Poisoning can Mimic Other Firefighter Health Issues

Annually, there are an estimated 20,000 residential structure fires that are caused by mattresses, pillows and bedding materials, all of which are likely to contain synthetic materials that release hydrogen cyanide when they burn or smolder.

The U.S. Fire Academy and the International Association of Fire Fighters (IAFF) have, for years, utilized the same National Institute for Occupational Safety and Heatlh (NIOSH) Firefighter fatality statistics to assist in driving the firefighter wellness initiatives.

These initiatives are based on the statistics that show approximately 50 percent of fireground fatalities are caused by cardiac arrest secondary to poor fitness levels. These statistics have caused a strong push throughout the entire fire service to strongly encourage all firefighters to work out harder and more frequently to ensure they are able to handle the rigors demanded by the job. But what if a portion of the fireground induced cardiac arrests where not caused by poor health but by a silent killer we have not assessed for during emergency treatment or the existing line of duty death investigations required for a firefighter to receive the Public Safety Officers Benefit?

One of the most recent theories currently being evaluated by the International Association of Fire Chiefs is the possibility of cyanide poisoning causing some portion of the cardiac arrests. This question is currently being discussed by Chief Bobby Halton, Chief Editor of Fire Engineering and has been delivered to various audiences around the country. The primary concern regarding cyanide is its ability to cause fatal health issues with firefighters and the inability or unavailability of assessing for the problem. The symptoms of cyanide poisoning mimic the signs and symptoms of a myocardial infarction.

These signs and symptoms of cyanide poisoning include:

  • Early signs of exposure to low concentrations:
  • Rapid breathing
  • Dizziness
  • Weakness
  • Nausea/vomiting
  • Eye irritation
  • Pink or red skin color
  • Rapid heart rate
  • Perspiration
  • Later signs of exposure to moderate-high concentrations
  • Loss of consciousness
  • Respiratory arrest
  • Cardiac arrest
  • Coma
  • Seizures

As you can see, early symptoms can masquerade as exhaustion (a sign of poor fitness?) or a cardiac event (a sign of poor fitness?), the secondary symptoms may be misconstrued as a singular event initiated by a myocardial infarction (poor fitness & poor nutrition?) when in fact, the problem may have been caused by undiagnosed cyanide poisoning.

Cyanide is found in a large variety of household products - generally considered to be a natural by-product of burning natural fuels such as wool, silk and leather. However, when one truly looks as the chemical make-up of the majority of household items, cyanide is part of almost any plastic-based product. Cyanide is regularly found in polyurethane, nylon, insulation, furniture cushioning, carpets and other building materials and home furnishings. Annually, there are an estimated 20,000 residential structure fires that are caused by mattresses, pillows and bedding materials, all of which are likely to contain synthetic materials that release hydrogen cyanide when they burn or smolder. These same materials when ignited cause a fire to burn two to three times hotter and faster than natural products, causing fires to reach flashover much quicker. As seen above, cyanide is more prevalent and has more significant impacts to the evolution of both the fire dynamics and the smoke by-products of the fire and gaseous environment.

The National Institute of Standards and Technology (NIST) investigated the Station Nightclub fire in West Warwick, Rhode Island, which caused 100 deaths in February 2003. The investigation showed that more than likely, the 100 deaths were caused by cyanide poisoning from the burning polyurethane utilized for sound enhancement on the walls. The NIST investigation included experiments simulating the fire in a test room with the same dimensions and containing similar materials as those in the nightclub the night of the fire. The experiments showed that within seconds of ignition of the fire, concentrations of carbon monoxide and hydrogen cyanide soared and oxygen levels plummeted. If then, rapid levels of carbon monoxide and hydrogen cyanide are generated during the initial phase of plastics based structure fire, and smoldering objects continue to off-gas during the overhaul phase, how many firefighters are currently inadvertently being poisoned because routing dictates the gas monitoring of carbon monoxide only? Current theories regarding the exposure to cyanide causes one to rethink how overhaul and post fire gas monitoring should occur.

A recent event occurred in Providence, RI, which brought the cyanide issue to the forefront. The Providence Fire Department and Ffirefighter Kenneth Baker responded to a commercial structure fire on March 23, 2006 at 125 Knight St. The structure fire was handled in an appropriate manner without any noticeable events. At 2:23 a.m. on March 24, 2006 firefighter Kenneth Baker suffered a heart attack while operating at another house fire at 70 Ralph St. Firefighter Baker was found to have had high levels of cyanide in his body. Firefighter Baker had previously worked the fire earlier in the shift, but did not work at the Broad Street fire that other crews had worked on. In the aftermath of the three fires, a total of 28 members sought medical follow-up, 27 of whom were tested for cyanide poisoning. Eight members were found to have elevated levels of cyanide, four of whom worked at the Broad Street fire, and four of whom worked at the Knight Street fire. Numerous other members reported symptoms consistent with cyanide poisoning, including headaches, weakness and fatigue, nausea, and shortness of breath.

Firefighter Baker was lucky in the progression of treatment he received at the hospital which saved his life. Firefighter Baker was evaluated at the hospital for a heart attack, which was how he presented. However, due to his profession, the ER doctor ordered a carboxyhemoglobin test to see if he was suffering from a carbon monoxide poisoning as well. It just so happened that another physician in the emergency room that night was showing a new group of interns around the teaching hospital and decided to show his interns how to draw bloods to check for cyanide poisoning as well as the carboxyhemoglobin (the compound that is formed when inhaled carbon monoxide combines with hemoglobin) test. It was this unanticipated blood test that diagnosed Baker has having cyanide poisoning which was causing an oxygen/blood perfusion mismatch. This systemic hypoxia was the cause of the heart attack.

The cyanide problem has gone unrecognized by firefighters and the medical community for various reasons. For example, symptoms of cyanide poisoning are similar and commonly attributed to carbon monoxide poisoning. The blood test for cyanide poisoning is not readily available in most hospitals. The test is done with blood drawn from an artery, usually the radial artery, and submitted to the lab for testing. One problem with this is that few in-house hospitals are capable of running the cyanide test. Those that are able to run the test take approximately four to six hours to get results back. For those hospitals that are unable to test for cyanide in-house, they generally send out the test and get results back within a week. This significant amount of time delays the treatment therapy making it useless: the half-life of cyanide in the body is one hour and if the body had an acute level, the patient will be dead before the results return.

Many of the firefighters who tested normal for cyanide after the fires may have had high levels of cyanide at the fire scenes and immediately thereafter, but due to the short half-life of cyanide and the length of time between the exposures and the blood draw, their cyanide levels returned to normal. Other firefighters who did not go for testing but experienced symptoms similar to those with the positive results may have also had toxic levels of cyanide immediately after the fire.

The combination of toxic gases in smoke can be lethal to anyone trapped inside a burning building and forced to inhale this deadly mixture. Several studies have shown both carbon monoxide and cyanide, independently and in combination with each other, can be deadly to those trapped in burning buildings.

  • A study conducted by the Paris Fire Brigade showed a direct relationship between blood cyanide concentration and occurrence of fire-related death, suggesting that cyanide contributed to many of the 43 fire-related deaths they studied.
  • Another study of a 1991 prison fire, which killed 35 inmates in Argentina, suggests hydrogen cyanide generated by the rapid thermal decomposition of the polyurethane mattresses was the most likely cause of death for these victims. The researchers found the carboxyhemoglobin saturation values in the victims was considered within the non-lethal range, while the victims blood cyanide levels all exceeded the lethal range.
  • Additional studies have shown that the combination of cyanide and carbon monoxide exposure in a structural and closed-space fire is frequent and potentially more dangerous than carbon monoxide alone.
  • Finally, studies have shown inhaling even sub-lethal amounts of cyanide can be dangerous resulting in increased confusion and incapacitation. This can result in decreased time to escape, inability to escape at all, and an increase in the likelihood of burns.

All of the above evidence creates a series of questions that need answers and force changes to existing procedures. Knowing the cyanide is much more prevalent and unanticipated at fires than previously known, fire departments need to evaluate post-fire scenes for cyanide as well as carbon monoxide. Even simpler, if post fire fuels are still off-gassing, SCBA's should be worn! Hospital physicians must be educated on the increased likelihood of firefighters presenting with cyanide induced cardiac events. As part of their evaluations, carboxyhemaglobin and cyanide levels should be drawn as soon as possible due to the short half-live of cyanide in the blood.

Cyanide antidote kits should be available in-house for therapy. The latest antidote, Cyano-kit Hydroxycobalamine has fast-tracked through the FDA to treat cyanide poisonings. This kit was cleared by the FDA in December, 2006. The Cyano-kit has the ability to combine with cyanide. The cobalt core of the kit has a Hydroxide molecule that is shed to grab onto the cyanide molecule instead. This converts the hydroxycobalamine to cyanocobalamin or vitamin B-12. The cyano-kit shows promising results in treating those individuals with high cyanide levels secondary to smoke inhalation as the Paris Fire Brigade currently does successfully in Europe.

It would be in the best interests of the line firefighters to convince their physician advisors to add Cyano-kits to all the ALS transport apparatus. Emergency departments would be another area to stock the Cyano-kits to ensure rapid treatment is available for those individuals who: were in a confined room fire, have soot around the nose/mouth and an altered mental status.

And finally, a line of duty death investigation is required if a firefighter has died within 48 hours of a structure fire to assist in ruling out death by cyanide poisoning. This will drive further evaluations of firefighters that were on the same call that may be exhibiting symptoms of a lower dose of cyanide. This will also assist in securing evidence for a Public Safety Officer's Benefit from the Department of Justice. The cyanide test needs to be added to the medical examiner's list of blood work that should be completed in a line of duty death investigation.

The fire service is just coming to grips with the concept of cyanide poisoning in a structure fire based environment. We need to embrace the idea that cyanide may be killing a larger portion of firefighters than previously known. But to track the possibility that a number of heart attacks may be caused by cyanide poisoning, we need to be sure that the proper statistics are being collected and disseminated. We also need to enbrace the idea that the new therapies may be able to reduce that number of cyanide poisonings by utilizing the new cyanide poisoning methods. With luck, we may have stumbled upon a treatable portion of the firefighter fatality numbers that we can erradicate.



  • Hydroxocobalamin as a Cyanide Antidote
    American Journal of Therapeutics. 13(2):161-165, March/April 2006. DesLauriers, Carol Ann *; Burda, Anthony M.; Wahl, Michael
  • Triage and initial treatment of house fire victims
    Service d'anesthesiologie, Brigade sanitaire cantonale, HUG, 1211 Geneve 14
Michael P. Lee is a Battalion Chief with the Cunningham Fire Protection District in Denver, CO. A veteran of over 20 years in the fire service, including training officer, he has 25 years of expierience as a pre-hospital paramedic. Michael started his career as a firefighter/paramedic and has worked his way through the ranks, including the training office, before his promotion to battalion chief and has taught on dozens of fire and rescue topics. Lee served as the safety officer for the Colorado Task Force 1 (CO-TF 1) during Hurricane Katrina in 2005 and is a A U.S. Navy veteran.