There are many types of hazards emergency service personnel deal with everyday. During any fire ground operation we have trained our personnel on the dangers of carbon monoxide poisoning resulting from fires. There is another danger to firefighters and victims which is less recognized, and that is acute cyanide poisoning. In 2005 there were 87 firefighter deaths in the United States. 4000 firefighters were injured by smoke inhalation, and it was estimated to be up to 80% of all fire fatalities are attributed to smoke inhalation. There has been mounting evidence that hydrogen cyanide is directly responsible for many deaths than previously assumed.
Where does cyanide poisoning come from? Ordinary materials we use everyday in our lives. Hydrogen Cyanide (HCN) is produced by high temperatures and low oxygen concentrations. The incomplete combustion of natural fibers such as wood, silk, cotton, and paperfavors the formula of cyanide gas. Synthetic polymers (Common man-made materials), include, insulations, carpeting, bedding, and building materials, which is found exclusively in most modern homesand our vehicles being produced today. Other small-scale users are photographic labs, blueprinting, engrave computer chips, clandestine drug labs and manufacturing phencyclidine (PCP) locations.
Small amounts of cyanide are present in the environment and in humans. So how much hydrogen cyanide gas can kill you? The Occupational Safety and Health Administration (OSHA) website [see http://www.osha.gov] under “Summary of toxicology” Hydrogen cyanide can cause rapid death due to metabolic asphyxiation. Death can occur within seconds or minutes of the inhalation of high concentrations of hydrogen cyanide gas. A recent study reports an estimated lethal concentration in humans of 3,404 parts per million (ppm) for a 1- minute exposure; other sources report that 270 ppm is fatal after 6 to 8 minutes, 181 ppm after 10 minutes and 135 ppm after 30 minutes.
(OSHA) also lists the threshold odor concentration for detection of hydrogen cyanide as 0.10 ppmas an 8 hour time weighted average (TWA) concentration, but exposed to smoke from burning materials will prevent the ability to smell HCN gas. The OSHA PEL also bears a "Skin" notation, which indicates that, the coetaneous route of exposure which including mucous membranes and eyes contributes to overall exposure. The National Institute for Occupational Safety and Health (NIOSH) lists a lower limit of 4.7 ppm for short term exposure limit. American Conference of Industrial Hygienists (ACGIH) has also assigned 4.7 ppm as a worker ceiling limits. Both (NIOSH) and (ACGIH) are more conservative than OSHA. The word “SKIN” by NIOSH and OSHA listing shows that hydrogen cyanide can be absorbed by the skin and eyes in addition to inhalation.
Although there is no quick test to confirm any HCN exposure in the field, there are signs and symptoms that can lead to assumption of possible exposure. The signs and symptoms sound and look familiar, disorientation or weakness/drowsiness, shortness of breath and chest tightness, headaches, bright red discoloration in skin, soot around mouth and nose. HCN exposures are quite similar to those of carbon monoxide (CO) exposure, but 24 times more deadly than CO. Specific indicator that is present in HCN exposures is rapid respirations. In most cases patient will maintain a pulse of 100 beats per minute or greater, and will not begin to feel better once placed in fresh air. Chronic effects HCN include respiratory arrest, eye irritation, palpitations, weakness, and paralysis. Treatment starts with removing the patient from the fire ground or hot zone. If the patient is wearing an air pack it should not be removed until after they are brought to clean air. Implement appropriate emergency treatment per your medical protocols.
Prevention starts with respiratory protection requirements (SCBA’s) and personal protection equipment (PPE’s), while operating on any fire ground or in hot zones. During overhaul operations (SCBA) & (PPE) should still be worn until the atmosphere can be declared safe by HCN detectors, along with the CO detectors. Company officers must enforce protection of their personnel and ensure (SCBA) & (PPE) are in place while on the fire ground. Train as you play, to ensure the comfort levels of our personnel while engaged in difficult operation such as climbing ladders, operating on roofs, and operating confined spaces. Post fire decontamination is a must. Take showers and change your clothes after each fire, along with washing your turnout gear per manufacturer’s recommendations.
All emergency service personnel must understand hydrogen cyanide is a silent killer. Departments need to educate and train there personnel accordingly. Develop standing operating procedures for detecting of hydrogen cyanide. Ensure that SCBA’s and PPE’s are in place while on the fire ground. Ensure your medical protocols address the treatment of hydrogen cyanide exposures. Additional information and other resources can be found at these websites: http://www.firesmoke.org/, http://www.osha.gov, http://www.cdc.gov/niosh/, http://www.acgih.org
Assistant Fire Chief
Kimball Township Fire Department
1970 Allen Rd. Kimball, MI 48074