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HomeMy WebLinkAbout202.018 - Carbon Monoxide and Hydrogen Cyanide Monitoring at Structure Fires STANDARD OPERATING PROCEDURES MANUAL TACTICAL OPERATIONS 202.018 CARBON MONOXIDE AND HYDROGEN CYANIDE MONITORING AT STRUCTURE FIRES EFFECTIVE: SEPTEMBER 2013 Current Revision Date: 10/7/20 Next Revision Date: 10/7/23 Author’s Name/Rank: Joshua Sellers, Engineer Review Level: 1 Administrative Support: Sherrie L. Badertscher, Management Analyst II Section 202.018 Page 1 of 7 PURPOSE The purpose of this policy is to provide Fresno Fire Department (FFD or Department) members standard operating procedures for the monitoring of carbon monoxide (CO) and hydrogen cyanide (HCN) gases at structure fires. APPLICATION This policy should be applied by all Department members operating within a structure following fire conditions. OPERATIONAL POLICY Members engaging in structural firefighting operations shall wear all structural firefighting personal protective equipment (PPE) until the incident commander determines such protection is no longer required. Self-contained breathing apparatus (SCBA) shall not be removed until the atmosphere is monitored and deemed safe. OPERATIONAL GUIDELINE All structure fires should be monitored after the fire is knocked down. Gas detection meters should not be exposed to active fire conditions. High levels of heat and increased amounts of contaminants can damage the instrument. Monitoring should only be completed utilizing a Department meter. Meters are located on all truck companies and hazmat units. If a company with an HCN meter is not on scene, the incident commander should request a unit with a meter to respond. Section 202.018 Page 2 of 7 PROCESS 1. Post Fire Environments: The post fire environment is dangerous due to irritants, toxic gases, and carcinogens in the atmosphere. Carbon monoxide (CO) and hydrogen cyanide (HCN) are toxic gases produced during combustion. CO is a colorless, odorless and tasteless gas. HCN is a colorless or pale-blue gas with a bitter, almond-like odor. SCBAs and PPE should not be removed until the atmosphere can be monitored and deemed safe. a. Environments where HCN is detected at 2 ppm or greater should be considered hazardous and SCBAs utilized. i. The short-term exposure limit (STEL) [skin] for HCN is 4.7 ppm. ii. HCN is immediately dangerous to life and health (IDLH) at 50 ppm. b. Environments where CO is detected at 25 ppm or greater should be considered hazardous and SCBAs utilized. i. The NIOSH recommended exposure limit (REL) time weighted average for 10 hours a day over a 40-hour workweek is 25 ppm. ii. The IDLH for CO is 1200 ppm. Note: If an operational HCN meter is not available at the scene, a reading of 20 ppm or lower of CO is required in order to operate without an SCBA. 2. Decontamination: a. Field decontamination of PPE/SCBA should follow the process as outlined in Standard Operating Procedure Manual, Section 202.021, On-Scene Cleaning Procedures for Personnel and PPE. b. Members should practice good personal hygiene by washing hands prior to drinking and eating in Rehab. Section 202.018 Page 3 of 7 c. Once an incident is under control, a random selection of the crews known to have been operating in the structure should have their PPE monitored. d. If turnout gear has a reading higher than 5 ppm CO, the gear should be cleaned again, per Standard Operating Procedure Manual, Section 202.021, On-Scene Cleaning Procedures for Personnel and PPE. i. Gear should be washed as soon as possible in an approved gear extractor. ii. Turnout gear, flash hood, and helmet ear flaps should be washed in an extractor per National Fire Protection Association (NFPA) 1851. iii. Gloves should be washed in the extractor with other gear. iv. Firefighters are to shower and change uniform as soon as practicable. 3. Reporting: The reporting officer will be responsible for recording any significant exposures during a structure fire. Any time members are operating outside the safe range without SCBA, a notation is to be made in the Tiburon report under the Fire Personnel Casualty section. The incident commander is to forward information, via email, to the EMS officer in reference to HCN exposures. The following information will be supplied: a. HCN and CO levels during the time of operation. b. Areas monitored with corresponding readings. i. How long members operated in the atmosphere. ii. Members operating in the hazardous atmosphere. c. Specifics concerning the call: i. Location. ii. Major materials, which burned or were greatly heated. Section 202.018 Page 4 of 7 iii. Units that responded. INFORMATION 1. Health Hazards: a. CO is an asphyxiant in humans. Inhalation of CO causes tissue hypoxia by preventing the blood from carrying sufficient oxygen. CO combines reversibly with hemoglobin to form carboxyhemoglobin. The reduction in oxygen-carrying capacity of the blood is proportional to the amount of carboxyhemoglobin formed (Gosselin, Smith, & Hodge, 1984). All factors that speed respiration and circulation accelerate the rate of carboxyhemoglobin formation; therefore, exercise, increased temperature, high altitude, and anemia increase the hazard associated with CO exposure (Gosselin, Smith, & Hodge, 1984). Other conditions that increase risk are hyperthyroidism, obesity, bronchitis, asthma, preexisting heart disease, and alcoholism (NLM 1993). In tests with human volunteers breathing 50 ppm CO (a concentration that produces 27 percent carboxyhemoglobin after an exposure of 2 hours), there was a significant decrease in time to onset of exercise-induced angina (Gosselin, Smith, & Hodge, 1984). CO can be transported across the placental barrier, and exposure in utero constitutes a special risk to the fetus (Gosselin, Smith, & Hodge, 1984). A carboxyhemoglobin level of 0.4 to 0.7 percent is normally present in the blood of adults. In cigarette smokers, the range is 4 to 20 percent, which places smokers at greater risk in exposure situations (Clayton & Clayton, 1982); (ACGIH, 1991). b. HCN can cause rapid death due to metabolic asphyxiation. Death can occur within seconds or minutes of the inhalation of high concentrations of HCN. Sources report 270 ppm is fatal after 6 to 8 minutes, 181 ppm after 10 minutes, and 135 ppm after 30 minutes (Hathaway, Proctor, Hughes, & Fischman, 1991). These levels are not uncommon during routine structure fires. Workers exposed to HCN at concentrations ranging from 4 to 12 ppm for 7 years showed an increase in symptoms, such as headaches, weakness, changes in taste and smell, irritation of the throat, vomiting, effort dyspnea, lacrimation, abdominal colic, precordial pain, and nervous instability (ACGIH, 1991). Workers exposed to low concentrations (not further specified) of HCN have developed enlarged thyroid glands (NLM, 1995). Section 202.018 Page 5 of 7 2. Signs and Symptoms of Exposure: a. Carbon Monoxide: i. Acute Exposure: The signs and symptoms of acute exposure to CO may include headache, flushing, nausea, vertigo, weakness, irritability, unconsciousness, and in persons with pre-existing heart disease and atherosclerosis, chest pain and leg pain (OSHA). ii. Chronic Exposure: Repeated bouts of CO poisoning may cause persistent signs and symptoms, such as anorexia, headache, lassitude, dizziness, and ataxia (OSHA). b. Hydrogen Cyanide: i. Acute Exposure: Acute exposure to HCN can result in symptoms including weakness, headache, confusion, vertigo, fatigue, anxiety, dyspnea, and occasionally, nausea and vomiting. Respiratory rate and depth are usually increased initially and at later stages become slow and gasping. Coma and convulsions occur in some cases. If cyanosis is present, it usually indicates respiration has either ceased or has been inadequate for a few minutes. If large amounts of cyanide have been absorbed, collapse is usually instantaneous; unconsciousness, often with convulsions, is followed almost immediately by death (Hathaway, Proctor, Hughes, & Fischman, 1991); (OSHA). ii. Chronic Exposure: Chronic exposure to cyanide can result in symptoms similar to those reported after acute exposure, e.g., weakness, nausea, headache, and vertigo (Hathaway, Proctor, Hughes, & Fischman, 1991). Dermatitis, itching, scarlet rash, papules, and severe nose irritation have also been reported (Parmeggiani, 1983). In addition, long-term exposures have produced thyroid changes, including frank goiter (Gosselin, Smith, & Hodge, 1984). Only occasionally has reference been made to eye irritation, conjunctivitis, or superficial keratitis developing after chronic exposure to HCN gas (Grant, 1986); (OSHA). Section 202.018 Page 6 of 7 If firefighters are found to have been operating in an IDLH atmosphere without SCBA or experiencing severe health effects, it is strongly recommended they be transported for advanced medical evaluation. HCN has a half-life of one hour; therefore, it is imperative the exposed firefighter be given immediate medical attention to include blood work and tested for HCN levels in the blood. Because this is somewhat new information, it is likely test results will be delayed; however, firefighters should still be treated and monitored by advanced medical personnel. It is important, when transported, the hospital be advised the firefighter was operating in a known hazardous environment containing CO and HCN. DEFINITIONS This section intentionally left blank. CROSS-REFERENCES Standard Operating Procures Manual Section 202.021, On-Scene Cleaning Procedures for Personnel and PPE ACGIH (1991), Documentation of the Threshold Limit Values and Biological Exposure Indices, 6th ed., Cincinnati, OH: American Conference of Governmental Industrial Hygienists Clayton, G., & Clayton, F. (1982), Patty's Industrial Hygiene and Toxicology, 3rd Edition, New York, NY: John Wiley & Sons Gosselin, R., Smith, R., & Hodge, H. (1984), Clinical Toxicology of Commercial Products, 5th ed., Baltimore, MD: Williams & Wilkins Grant, W. (1986), Toxicology of the Eye, 3rd ed., Springfield, IL: Charles C Thomas Hathaway, G. J., Proctor, N. H., Hughes, J.P., & Fischman, M.L. (1991), Proctor and Hughes' Chemical Hazards of the Workplace, 3rd Edition, New York: Van Nostrand Reinhold NLM (1995), Hazardous Substances Data Bank: Hydrogen Cyanide, Bethesda, MD: National Library of Medicine Section 202.018 Page 7 of 7 OSHA (n.d.), Occupational Safety and Health Guideline for Carbon Monoxide, Retrieved 12 31, 2012, from United States Department of Labor; Occupational Safety and Health Administration; Occupational Safety and Health Guidelines: http://www.osha.gov/SL TC/health guidelines/carbon monoxide/recognition.html Parmeggiani, L. (1983), Encyclopedia of Occupational Health and Safety, 3rd rev. ed., Geneva, Switzerland: International Labour Organisation.