PREPUBUCATIQN COPY NIOSH •CDPHE • CPSC • OSHA • EPA SEPTEMBER 1996 Preventing Carbon Monoxide Poisoning from Small Gasoline-Powered and Tools U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES Public Health S«rvlc« Centers for Disease Control and Prevention National Institute for Occupational Safety and Health ------- ------- DISCLAIMER Mention of any company or product does not constitute endorsement by the National Institute for Occupational Safety and Health, the Colorado Department of Public Health and Environment, the Consumer Product Safety Commission, the Occupational Safety and Health Administration, or the U.S. Environmental Protection Agency. This document is in the public domain and may be freely copied or reprinted. Copies of this and other documents are available from Publications Dissemination, EID National Institute for Occupational Safety and Health 4676 Columbia Parkway Cincinnati, OH 45226-1998 Fax number (513) 533-8573 Telephone number: 1-800-3S-NIOSH (1-800-356-4674) E-mail: pubstaft@niodst1.em.cdc.gov To receive other information about occupational safety and health problems, call 1-800-35-NIOSH (1-800-356-4674), or visit the NIOSH Home Page on the World Wide Web at http^/www.cdc.gov/niosh/homepage.html DHHS (NIOSH) Publication No. 96-118 ii • , - ' ' • ' ' ' •/'•'''•.•••-••' ------- ------- PREFACE This ALERT is the joint product of a combined effort among the following agencies: • The National Institute for Occupational Safety and Health (NIOSH) • The Colorado Department of Public Health and Environment (CDPHE) • The U.S. Consumer Product Safety Commission (CPSC) • The Occupational Safety and Health Administration (OSHA) • The U.S. Environmental Protection Agency (EPA) \ ' • ' . --•-'•_ Each agency has a unique role in protecting either workers/consumers or the general public from health and safety hazards. Because of their common interest in prevention of carbon monoxide (CO.) poisonings resulting from widespread use of small gasoline- powered engines and tools in enclosed or confined spaces, the agencies elected to work together to produce a joint document to address this problem and provide recommen- dations for prevention. Such a combined effort avoids duplication and confusion from multiple documents and promotes efficient use of government resources. iii ------- ACKNOWLEDGMENTS Principal contributors to the development of this joint ALERT include: • Janet J. Ehlers, Jane B. McCammon, Dennis O'Brien, G. Scott Earnest, R. Leroy Mickelsen, Mary L. Woebkenberg, and Jerome P. Flesch (NIOSH) • Allison Hawkes and Lyle McKenzie (CDPHE) * • Elizabeth Leland (CPSCJ • Edward Stein (OSHA) • Richard Leukroth and John Girman (EPA) Iv ------- NIOSH • CDPHE • CPSC • OSHA • EPA '! • ALERT Preventing Carbon Monoxide Poisoning from Small Gasoline-Powered Engines and Tools WARNING! Indoor use of gasoline-powered engines and tools is risky business. Many people using gasoline-powered tools such as high-pressure washers, concrete cutting saws (walk-behind/hand-held), power trowels, floor buffers, welders, pumps, com- pressors, and generators in buildings or semi-enclosed spaces have been poisoned by carbon monoxide (CO). CO can rapidly accumulate, even in areas that appear to be well ventilated, and build up to dangerous and fatal concentrations within minutes. Examples of such poisonings include the following: A farm owner died of cd poisoning while using an 11-horsepower gasoline- powered pressure washer to clean his bam. He had worked about 30 minutes before being overcome. A municipal employee at ah indoor water treatment plant lost consciousness while trying to exit a 59,000-cubic-fopt room where he had been working with an 8-horsepower, gasoline-powered pump. Doors adjacent to the work area were open while he worked. His hpspital diagnosis was CO poisoning. Five workers were treated for CO poi- soning after using two 8-horse-power gasoline-powered, pressure washers in a poorly ventilated underground parking garage. f A plumber used. a gasoline-powered concrete saw in a basement with open doors and windows and a cooling fan. He experienced a severe headache and dizziness and began to act in a paranoid manner. His symptoms were related to CO poisoning. These examples show a range of effects caused by CO poisoning in a variety of work settings with exposures that occurred over different time periods and with different types of ventilation. Workers in areas with closed doors and windows were incapacitated within minutes. Opening doors and windows or operating fans does NOT guarantee safety. CO is a dangerous poison. Operating gasoline-powered engines and tools indoors is RISKY BUSINESS, : - Please distribute copies to users. ------- RECOMMENDATIONS It is not widely known that small gasoline-powered engines and tools present a serious health hazard. They produce high concentrations of carbon monoxide, a poisonous gas that can cause illness, permanent neurological damage, and death. Because it is colorless, odorless and nonirritating, CO can overcome exposed persons without warn- ing. Often there is little time before a person experiences symptoms that inhibit their ability to seek safety. Prior use of equipment without incident has sometimes given users a false sense of safety; such users have been poisoned on subsequent occasions. Recommendations for preventing CO poisoning are provided below for employers equipment users, tool rental agencies, and tool manufacturers. All Employers and Equipment Users: • Do NOT allow the use of or operate gasoline-powered engines or tools Inside buildings or in partially enclosed areas unless gasoline engines can be located outside away from air intakes. Use of gasoline-powered tools indoors where CO from the engine can accumu- late can be fatal.- An exception to this rule might be an emergency rescue situation where other options are not available, and then only when equipment operators, assisting personnel and the victim are provided with supplied-air respirators. • Learn to recognize the. symptoms and signs of CO overexposure: headache, nausea, weakness, dizziness, visual disturbances, changes in personality, and loss of consciousness. Any of these symptoms and signs can occur within minutes of usage. • Always place the pump and power unit of high-pressure washers outdoors so . that engine exhaust is not drawn in- doors where the work is being done. Run only the high-pressure wash line inside. • Consider the use of tools powered by electricity or compressed air if they are . available and can be used safely. For example, electric-powered tools present an electrocution hazard and require specific precautions for safety. • If compressed air is used, place the gasoline-powered compressor out- doors away from air intakes so that engine exhaust is not drawn indoors where the work is being done. • Where potential sources of CO exist, use personal CO monitors equipped with audible alarms to warn workers when CO concentrations are too high. Employers Should Also: « Conduct a workplace survey to identify all potential sources of CO exposure. • Educate workers about the sources and conditions that may result in CO poison- ing as well as the symptoms and control of CO exposure. • Always substitute less hazardous equipment whenever possible, or use equipment that allows for the placement of ------- gasoline-powered engines outdoors at a safe distance from air entering the building. .• • Monitor employee CO exposure to de- termine the extent of the hazard. Equipment Users Should Also: • Substitute less hazardous equipment whenever possible. Use electric tools or tools with engines that are separate from the tool for placement outdoors. • Leam to recognize the warning symp- toms of CO poisoning. • If you have any symptoms, immediately turn off equipment and go outdoors or to a place with uncontaminated air. • Call 911 or another local emergency number for medical attention or assis- tance if symptoms occur. Do NOT drive a motor vehicle—get someone else to drive you to a health care facility. • Not return to the work area until the tool has been deactivated and measured CO concentrations are below accepted guidelines and standards. I - - V • Watch coworkers for the signs of CO toxicity. Tool Rental Agencies Should: • Put warning labels on gasoline-powered tools—for example: WARNING —CARBON MONOXIDE PRODUCED DURING USE CAN KILL—DO NOT USE INDOORS OR IN OTHER SHEL- TERED AREAS. t Tell renters that gasoline-powered tools should NOT be used indoors and ex- plain why. Recommend safer tools for intended use, if available. Have portable, audible .CO monitors for rent and encourage the use of them. Provide renters with educational mate- rials like this information sheet. Tool Manufacturers Should: • Design tools that can be used safely indoors. • Provide warning labels for existing and new gasoline-powered equipment—for example: WARNING—CARBON MONOXIDE PRODUCED DURING USE CAN KILL—DO NOT USE IN- DOORS OR IN OTHER SHELTERED AREAS. • Provide recommendations on equip- ment maintenance to reduce CO emissions. • Recommend the use of portable, audi- ble CO monitors with small gasoline- powered engines. ------- FOR MORE INFORMATION For additional information, see ALERT: Preventing Carbon Monoxide Poisoning from Small Gasoline-Powered Engines and Tools [DHHS (NIOSH) Publication No 96-118] Single copies of the Alert are available free from the following: "' / • Publications Dissemination, EID National Institute for Occupational Safety and Health 4676 Columbia Parkway Cincinnati, OH 45226 Fax number: (513) 533-8573 Phone number: 1-800-35-NIOSH (1-800-356-4674) E-mail: pubstaft@rtiosdt1.em.cdc.gov This Alert is the joint product of a combined effort among the following agencies: • The National Institute for Occupational Safety and Health (NIOSH) • The Colorado Department of Public Health and Environment (CDPHE) * The U*S* Consumer Product Safety Commission (CPSC) • The Occupational Safety and Health Administration (OSHA) • The U.S. Environmental Protection Agency (EPA) DHHS (NIOSH) Publication No. 96-118a ------- NIOSH • CDPHE • CPSC • OSHA • EPA -'•-! \ ALERT! Preventing Carbon Monoxide Poisoning from Small Gasoline-Powered Engines and Tools WARNING! Do not use equipment and tools powered by gasoline engines inside buildings or other partially enclosed spaces unless the gasoline engine can be placed outdoors away from air intakes. Hundreds of people performing many different tasks have been poisoned because small gasoline-powered engines and tools produced hazardous concentrations of carbon monoxide (CO) even in relatively open buildings: • In December"! 992, a farm owner found his 12-year-old son unconscious near the door of a swine farrowing building (birthing barn) in Iowa. The boy had been working alone, using an 11 -horsepower, gasoline-powered pressure washer for about 1/2 hour to clean the building. ' • In January 1993, a 33-year-old farm owner in Iowa died of carbon monoxide poisoning while using an 11 -horsepower, gasoline-powered pressure washer to clean his swine farrowing barn. He had worked about Vz hour before being overcome. ' , • In January 1993, a 60-year-old drywall finisher in Colorado collapsed and fell from the scaffold on which he was standing. He was using a small gasoline-powered compressor to apply a textured surface to a cathedral ceiling in a house. Although he landed on a balcony below, escaping further injury, he was confused and unable to identify an escape route from the building. He was rescued by coworkers who saw him beckoning for help at the patio door. • In February 1993, a 30-year-old plumber in Colorado developed a severe head- ache and dizziness, and began to demonstrate paranoid behavior which was later diagnosed as CO poisoning. He had worked for 2 to 3 hours using a gasoline- powered concrete cutter to access pipes in a basement. He and his supervi- sor anticipated possible problems related to the exhaust from this equipment and had set up what they considered to be adequate ventilation (opened doors and windows, placed cooling fans near the cutter and farther down the hall). Carbon Monoxide Poisoning ------- • In June 1994, five workers in Washington, D.C., who experienced dizziness, confusion, headaches, and nervousness were treated for CO poisoning after using two 8-horsepower, gasoline-powered pressure washers for 4 hours in an empty, poorly ventilated, underground parking garage. When one of the five workers collapsed at the worksite, coworkers carried him outside, remained with him for a short time and then, unaware of the hazard, re-entered the hazardous worksite. Only after a second worker collapsed did workers recognize the hazard, evacuate the environment, and seek help. • In October 1994, a 37-year-old municipal employee at an indoor water treatment facility in Colorado lost consciousness while trying to exit a 59,000 cubic foot room where he had been working with an 8-horsepower, gasoline-powered water pump for4 hours. • In December 1994, a previously healthy 59-year-old owner/operator of a flooring installation business in Colorado experienced headache and dizziness after working for 2!& hours in the stairwell of a building containing a gasoline-powered generator supplying power to the construction site. He left the building and rested in his car. Upon returning to the stairwell, he collapsed in a grand mal seizure related to CO poisoning. These are examples of the many situations in which people have been poisoned because they did not recognize the danger of using small gasoline-powered engines indoors. These poisoninqs can occur quickly, even in the presence of what many would consider "adequate ventilation" and in areas that many would define as relatively open spaces such as parking garages. HEALTH EFFECTS CO is a lethal poison that is produced when fuels such as gasoline are burned. It is one of many chemicals found in engine exhaust, and can rapidly accumulate even in areas that might appear to be well ventilated. Because CO is colorless, tasteless, odorless, and nonirritating, it can overcome the exposed person without warning. It produces weakness and confusion, depriving the person of the ability to seek safety. "\ CO poisons primarily by tightly binding to hemoglobin in the blood (forming carbox^- hemoglobin), replacing oxygen, and reducing the oxygen-carrying capacity of the blood. CO may also poison by binding to tissues and cells of the human body and interfering with their normal function. Persons with pre-existing heart disease are at increased risk. Fetuses of pregnant women are also at increased risk—especially when mothers are exposed to high CO levels. Recognizing early warning signs of CO poisoning is sometimes difficult because early symptoms of CO exposure (headache, dizziness, and nausea) are nonspecific and may be mistaken for symptoms of other illnesses such as colds, flu, or food poisoning. Confusion and weakness can inhibit a person's ability to escape the hazardous environment. Carbon Monoxide Poisoning ------- The severity of symptoms of CO exposure is influenced by three main factors- (1) the concentration of CO in the environment; (2) how long the exposure lasts; and (3) work load and breathing rate. In general, assuming that users of gasoline-powered engines are engaged in at least a moderate level of activity, exposure to CO concentrations of 80-100 parts per million (ppm) for 1 to 2 hours can result in decreased exercise tolerance and, in persons who are at risk, may bring on chest pain and cause irregular heartbeat [EPA 1991 a]. Symptoms associated with CO exposure concentrations of 100 to 200 ppm include headache, nausea, and mental impairment. More serious central nervous system effects, coma, and death are associated with CO exposure concentrations of 700 ppm or greater for an hour or more [llano and Raffin 1990; Forbes et al. 1945]. Symptoms of nervous system effects include staggering, confusion, changes in personality, and muscle aches. These symptoms may continue or.occur for several days to several weeks after the exposure stops and the poisoned person has apparently recovered. Victims of CO poisoning should be immediately removed from the exposure site and given 100% oxygen. Hyperbaric chambers provide oxygen under pressure and are sometimes necessary in cases of serious CO poisoning. CURRENT STANDARDS AND RECOMMENDED GUIDELINES Organizations set standards of make recommendations for exposure to hazardous substances based on assumptions inherent to their regulatory oversight or authority Differences in the stated values reflect variations in the place, duration, characteristics of the population, or proposed use. Workplace/Industry . the current Occupational Safety and Health Administration (OSHA) permissible expo- sure limit (PEL) for carbon monoxide is 50 ppm as an 8-hr time-weighted average (TWA) [29 CFR 1910.1000*]. The NIOSH recommended exposure limit (REL) for CO is 35 ppm TWA and a ceiling limit (CL) of 200 ppm [NIOSH 1992]. The NIOSH recommended immediately dangerous to. life and health concentration (1DLH) for CO is 1,200 ppm. The IDLH is the concentration which could result in death or irreversible health effects, or prevent escape from the contaminated environment within 30 minutes. The American Conference of Governmental Industrial Hygienists (ACGIH) has adopted a threshold limit value (TLV) for CO of 25 ppm TWA [ACGIH 1992a]. Ambient Air/Residential Settings The U.S. Environmental Protection Agency (EPA) has established an ambient (outdoor) CO air quality Federal standard off 9 ppm for an 8-hr exposure and 25 ppm for short-term (1-hr) exposure [EPA 1991 a]. The Consumer Product Safety Commission (CPSC) staff recommends that long-term exposures to CO in indoor environments be limited to less than 15 ppm as an 8-hr TWA and 25 ppm for 1 hr, but product-specific recommen- dations for CO may vary depending on expected usage patterns and exposure. •Coda of Federal Regulations. See CFR in references. Carbon Monoxide Poisonfna ,3 ------- DATA SUMMARIZING CO POISONINGS Illness related to CO exposure is probably underestimated because workers with mild symptoms may go untreated or medical providers may not recognize their symptoms as CO poisoning. In addition, persons may not recognize the cause of their symptoms unless coworkers and other persons become ill at the same time. Two surveys assessing individuals' beliefs,' knowledge, and risk perceptions regarding CO suggest that many people are unaware of the hazards associated with CO. In 1993, NIOSH assessed flood victims' risk perceptions associated with CO poisoning from using equipment powered by small engines (e.g., gasoline-powered pressure washers indoors to cleanup flood-related debris) [Greife et al. 1995]. Many of the 4.16 respondents (26%) incorrectly believed that with only a window open, the use of a gasoline-powered engine indoors would be safe. A majority of respondents (54%) and 92% of respondents between the ages 12 and 20, incorrectly believed that it was safe to operate a gasoline- powered engine indoors with windows and doors open and an exhaust fan running. In a second survey, during follow-up investigations of nonfatal, unintentional CO poisoning in residential settings in Connecticut between November 1993 and March 1994, inves- tigators interviewed 36 victims or their adult representatives [CDC 1995b]. Many of the victims of CO poisoning (poisoning was related to heating systems, .gas appliances, and fireplaces) still demonstrated a lack of knowledge about prevention strategies. When asked to list prevention methods, 14% were unable to list any method, 44% listed appropriate maintenance of appliances, 30% listed the use of a CO detector, and 14% listed proper ventilation. . Reports from a number of sources show CO poisoning from the use of gasoline-powered tools indoors happens frequently: • OHNAC: The NIOSH-sponsored Occupational Health Nurses in Agricultural Communities (OHNAC) Surveillance Program identified 18 cases of CO poisoning related to the use of small engines; 17 cases occurred in less than 3 years [CDC 1993; Ehlers 1994]. Although only one case was a fatality, at least three cases could have been fatal had the victims not been found by coworkers or family members, removed from the hazardous environment, and taken for medical care. At least four were overcome in about Vz hour. Persons working in open environments (e.g., doors and windows open and exhaust fans operating) began developing symptoms in as little as 1 hour of constant work or as much as 7 hours of intermittent exposure. All interviewed persons reported being unaware that they could be poisoned in a short time and that CO can attain hazardous levels inside buildings with windows and doors open. Several victims, although appearing obviously confused and ill to family members at the worksite, were unaware of their impaired condition and sought medical help only at the Insistence of family members. Seven of the 18 incidents occurred among Iowa farmers using pressure washers to clean animal housing between January 1992 and March 1994. Of the other 11 cases, 7 occurred while using pressure washers to clean animal housing Carbon Monoxide Poisoning ------- elsewhere or in other years, and 4 occurred while using gasoline-powered pressure washers or concrete saws to clean up after floods. Colorado Department of Public Health and Environment (CDPHE): In Colorado, 40% (135) of all work-related, CO poisonings reported to CDPHE since 1985 have been related to the use of gasoline-powered equipment [CDPHE 1996]. Other sources of exposure associated with reported occupational poisonings in Colorado include automobile exhaust (25% of poisonings) and furnaces (12%). Seventeen of the 135 workers poisoned by gasoline-powered equipment lost consciousness during their exposure to emissions and two workers died. The 135 poisonings were primarily caused by concrete cutting saws (28 workers), power trowels (15 workers), high pressure washers (14 workers), compressors (10 workers), welding equipment (9 workers), and floor buffers (9 workers). Other equipment causing poisonings included jackhammers, pumps, carpet cleaners, and paint sprayers. Information about where the 135 poisoned workers were using gasoline-pbwered equipment was available in 115 incidences; 110 of these 115 (96%) poisonings occurred indoors. George Washington University (GWU): Seven worker poisonings related to the emissions from gasoline-powered tools used indoors have also been identified by the GWU Emergency Department Surveillance Project. Five of these poison- ings occurred in June 1994 and were discussed above (workers using a pressure washer in an empty underground parking garage) [CDC 1995a]. Two additional workers were poisoned while using gasoline-powered saws. California: A study of all death certificates in the State of California during the 10-year period from 1979-88 showed 444 deaths due to unintentional carbon monoxide poisoning [CDHS 1993]. Of these deaths, 23 (5%) were caused, by small engine exhaust. • National Estimates: There is no complete U.S. database for this problem. According to the U.S. Bureau of Labor Statistics (BLS) there were hearty 900 work-related CO poisonings resulting in death or illness in private industry in the United States in 1992 (32 deaths and 867 nonfatal poisonings) [BLS 1992a,b]. CPSC estimates that in 1992, the latest year for which data are available, there were 212 carbon monoxide deaths associated with the use of household fuel- burning appliances. Thirteen of these deaths were reported to have involved the use of gasoline-powered appliances [NCHS/CPSC1992]. In 1994, the latest year for which data are available, CPSC estimates that 3,900 carbon monoxide injury incidents occurred where an average of two to three persons per incident were treated in hospital emergency rooms. Of these 3,900 incidents, approximately 400 incidents were associated with the use of gasoline-powered appliances [CPSC 1994]. ; Carbon Monoxide Polsonfna - 5 ------- ENVIRONMENTAL MEASUREMENTS AND MODELING DOCUMENT RAPID CO BUILDUP Three of the above groups measured CO concentrations after the CO poisoning incidents in the same or similar exposure situations to estimate how quickly dangerous CO concentrations developed. A fourth group modeled the time to reach dangerous CO concentrations. . • OHNAC: NIOSH measured the generation of CO by a gasoline-powered pressure (GPP) washer using a 5.5 horsepower (hp) engine under environmental condi- tions comparable to those experienced by the farmers using pressure washers described in this report [Venable et al. 1995]. A 5.5 hp GPP washer was operated- inside a double-car garaoe, 8,360 ft3 building (range in cases: 3,420 ft3 to 10,080 ft3) using two ventilation scenarios. In the first or "worst case" scenario, .all doors, windows and vents were closed; breathing zone concentrations of CO reached 200 ppm in 5 minutes, 1,200 ppm (IDLH value) within 15 minutes and continued to increase above 1,500 ppm in 19 minutes. In the second or "best case" scenario, the two double-car garage doo.rs and one window were all left open and the vent unsealed; breathing zone concentrations of CO reached 200 ppm within 3 minutes and peaked at 658 ppm within 12 minutes. The results from the simulations indicate that acutely toxic concentrations of CO greater than 200 ppm (NIOSH ceiling) can be quickly generated within 3 to 5 minutes near a pressure washer operated indoors, even when passive ventilation is provided and IDLH concentrations of 1,200 ppm can be generated rapidly in enclosed spaces. • CDPHE: The Colorado Department of Public Health and Environment measured or recreated exposures in four poisonings related to the use of gasoline-powered tools indoors [CDPHE 1996]. First, CDPHE attempted to estimate the CO exposure of the drywall texturizer discussed earlier by sampling the air at another construction site where he was doing similar work. On the day of. the air sampling, the gasoline-powered com- pressor was placed just outside the garage door. Because of the way that the equipment was designed and oriented, exhaust from the engine on the compres- sor went directly into the house when the garage door was open. As is usual for this operation, all windows and external doors in the home had been closed and sealed with tape and paper to protect the surfaces from the texturing material and maintain the proper conditions for drying. The concentration of CO at the tailpipe of the compressor engine was substantially greater than 1,000 ppm (this was the upper limit of the testing equipment). Within the first 20 minutes of •the operation, CO concentrations.as high as 410 ppm were measured in the basement of the home, and as high as 322 ppm where the worker was standing. CDPHE asked the worker to open the windows and external doors on the upper floor of the duplex because of concerns about this concentration of exposure. CO Carbon Monoxide Poisoning ------- concentrations within the house dropped to approximately 30 ppm when that was done, but this is not the way the process is usually carried out. In response to the second incident, another GO poisoning related to the use of an 8-horsepower pressure washer in a 30,000 cubic foot room of a municipal construction project, CDPHE asked to run the_same pressure washer in the same room a few days later; There was no mechanical ventilation in this room because the facility was not yet operational. The pressure washer was placed approxi- mately 15 feet from one comer of the room (the same place the worker had placed it on the day of the poisoning). The power unit was an integral part of the washer. Again, the CO concentration atthe engine exhaust pipe was greaierthan 1,000 ppm, the highest Concentration CDPHE could measure at the time. CDPHE measured CO concentrations as high as 450 ppm at several locations in the room within 20 minutes of activation of the washer engine, and 546 ppm approximately 50 minutes after the washer engine was activated. The test was then terminated. ' In a third incident, CDPHE asked the managers of the enclosed municipal water .treatment plant to recreate the exposure situation encountered by the worker mentioned before who was using the 8-horsepower pump in the 59,000 cubic foot room (48 x 88 x 14 feet). This room was only partially enclosed so that employees could observe operations in the room from the level above. Outside air was introduced into the area through a forced-air heating system that was running on the day of the poisoning and on the day of air sampling. External doors to the treatment plant were opened on both days as well. Ten minutes after the pump engine was started, CO concentrations as high as 395 ppm were measured within 7 feet of the pump, near where the employee was standing for much of the time on the day of the poisoning. CO concentrations 25 feet from the water pump rose to as high as 193 ppm during the 20-minute test. CDPHE returned to the room one hour after the water pump was stopped and measured 40 ppm of CO. Finally, in January 1996, two Colorado workers were poisoned as a result of operating a gasolinerpowered, 5-horsepower, walk-behind concrete saw during a remodeling project. The machine was three years old and used 2 to 3 times per year. The workers operated the saw for about an hour and a half inside what had previously been two bathrooms (the dividing wall had been removed, the area of the room was 2,332 cubic feet). The workers were cutting a hole in the floor to allow access to pipes below the floor. The two doors to the room were open and the bathroom ventilation system was operating when these poisonings occurred. The day after the poisonings occurred, the work in this bathroom was continued with two differences. A cooling fan was used this time in an effort to better move CO from the room, and the saw was operated for shorter periods of time (the periods of operation were not clearly defined but were thought to be fifteen to thirty minutes in duration). CDPHE recreated the second day's operating condi- tions to measure CO concentrations in the room. The NIOSH ceiling limit of 200 ppm was exceeded within the first minute of operation. Within five minutes Carbon Monoxide Poisoning 7 ------- of operation, the CO concentration within the room reached 842 ppm, at which point the demonstration was discontinued (See Figure 1). • GWU: In the poisoning incident where five workers were using pressure washers in an underground garage, the Fire Department measured 648 pprn CO one hour afterthe washers had been turned off (washers had been running forthree hours). • NIOSH: NIOSH engineers modeled the time required for a gasoline-powered, 5 horsepower, 4-cycle engine to reach the 200 ppm (ceiling) and 1,200 ppm immediately dangerous to life and health (IDLH) CO concentration for room sizes of 1,000 to 100,000 ft3 and general ventilation rates of 1 to 20 air changes per hour (ACH) [ACGIH 1992b]. The CO generation rate used in the model was 670 grams/hp-hr based on data from a 1991 EPA study [EPA 1991 b]. Ideal mixing was assumed. Under .actual conditions, if mixing were poor, hazardous concen- trations could develop more quickly. In the small 1,000 ft3 roorri, the ceiling concentration of 200 ppm was reached in approximately 0.1 minute, and the IDLH was reached in less than 1 minute at all air flow rates. In the medium 10,000 ft3 room, the IDLH was reached in approximately 7 minutes for 1 air change per hour and approximately 10 minutes for 5 air changes per hour. These models demon- strate that for rooms up to 10,000 ft3, the NIOSH ceiling limit of 200 ppm was exceeded in less than 2 minutes even with general ventilation rates as high as 20 air changes per hour. In no case would it be possible to operate an engine for 8 hours without exceeding the NIOSH REL of 35 ppm. (See Figures 2 through 4). CO Concentration versus time (2,332 cubic foot room) ENGINE STOPPED, (842 ppm) Ceiling = 200 ppm ENGINE STARTED 4 6 8 10 12 14 Time (minutes) Figure 1. Actual CO concentration measured inside a 2,332 ft3 bathroom with a gasoline-powered 5 hp concrete saw operating (doors open, cooling fan, and ventilation running). 8 Carbon Monoxide Poison'ma ------- CO Concentration versus time (I,pOO cubic foot room) 2,000 — 1ACH -t-5ACH -*-10 ACH ^-15 ACH -*- 20 ACH 0.4 0.6 0.8 Time (minutes) Figure 2. Calculated CO concentration generated by a 5 hp, 4-cycle gasoline-powered engine in a 1,000 ft3 room with various air changes per hour (ACH). CO Concentration versus time . (10,000 cubic foot room) 3,000 ACH ACH * 10 ACH ;"-15 ACH ^20 ACH 2 4 8 10 12 14 16 18 Time (minutes), Figure 3. Calculated CO concentration generated by 5 hp, 4-cycie gasoline-powered engine in a 10,000 ft? room with various air changes per hour (ACH). Carbon Monoxide Poisoning ------- CO Concentration versus time (100,000 cubic foot room) 700 5 10 15 20 25 30 35 40 45 50 Time (minutes) Figure 4. Calculated CO concentration generated by a 5 hp, 4-cyde gasoline-powered engine in a 100,000 ft? room with various air changes per hour (ACH). RECOMMENDATIONS It is not widely known that small gasoline-powered engines and tools present a serious health hazard. They produce high concentrations of carbon monoxide, a poisonous gas that can cause illness, permanent neurological damage, and death. Because it is colorless, odorless and nonirritating, CO can overcome exposed persons without warn- ing. Often there is little time before a person experiences symptoms that inhibit their ability to seek safety. Prior use of equipment without incident has sometimes given users a false sense of safety; such.users have been poisoned on subsequent occasions. Recommendations for preventing CO poisoning are provided below for employers, equipment users, tool rental agencies, and tool manufacturers. All Employers and Equipment Users: • DO NOT allow the use of or operate gasoline-powered engines or tools inside buildings or in partially-enclosed areas unless gasoline engines can be located outside away from air intakes. Use of gasoline-powered tools indoors where CO from the engine can accumulate can be fatal. • An exception to this rule might be an emergency rescue situation where other options are not available, and then only when equipment operators, assisting personnel and the victim are provided with supplied-air respirators. 10 Carbon Monoxide Poisoning ------- • Learn to recognize the signs and symptoms of CO overexposure: headache, nausea, weakness, dizziness, visual disturbances, changes in personality, and loss of consciousness. Any of these sighs and symptoms can occur within minutes of usage. • Always place the pump and power unit of high-pressure washers outdoors so that engine exhaust is not drawn indoors where the work is being done. Run only the high-pressure wash line inside. ^ • Consider the use of tools powered by electricity or compressed air if they are available and can be used safely. For example, electric-powered tools present an electrocution hazard,and require specific precautions for safety. • If compressed air is used, place the gasoline-powered compressor outdoors away from air intakes so that engine exhaust is not drawn indoors where the work is being done. ' • Where potential sources of CO exist, use personal CO monitors equipped with audible alarms to warn workers when CO concentrations ar,e too high. More information on GO monitors is contained in the appendix. Employers Should Also: • Conduct a workplace survey to identify all potential sources of CO exposure. ••• Educate workers about the sources and conditions that may result in CO poison- ing as well as the symptoms and control of CO exposure. • Always substitute less hazardous equipment if possible. Use equipment that allows for the placements gasoline-powered engines outdoors at a safe distance from air entering the building. • Monitor employee CO exposure to determine the extent of the hazard. , "\ . .,...» ' • . • -..-._ • v Equipment Users Should Also: . • Substitute less hazardous equipment whenever possible. Use electric tools or tools with engines that are separate from the tool for placement outdoors. • Learn to recognize the warning symptoms of CO poisoning. • If you have any symptoms, immediately turn off equipment and go outdoors or to a place with uncontaminated air. • ' • . . ••; ; ' y .- • - ,' .''.-. Carbon Monoxide PoJsonfna 11 ------- • Call 911 or another local emergency number for medical attention or assistance if symptoms occur. Do NOT drive a motor vehicle—get someone else to drive vou to a health care facility. • Not return to the work area until the tool has been deactivated and measured CO concentrations are below accepted guidelines and standards. • Watch coworkers for the signs of CO toxicity. Tool Rental Agencies Should: • Put warning labels on gasoline-powered tools—for example: WARNING- CARBON MONOXIDE PRODUCED DURING USE CAN KILL—DO NOT USE INDOORS OR IN OTHER SHELTERED AREAS. • Tell renters that the tool should NOT be used indoors and why. • Recommend safer tools for intended use, if available. • Have portable, audible CO monitors for rent and encourage the use of them. • Provide renters with educational materials like this information sheet. • Tool Manufacturers Should: * * . • ' • Design tools that can be used safely indoors. • Provide warning labels for existing and new gasoline-powered equipment—for example: (WARNING—CARBON MONOXIDE PRODUCED DURING USE CAN KILL—DO NOT USE INDOORS OR IN OTHER SHELTERED AREAS). • Provide recommendations on equipment maintenance to reduce CO emissions. • Recommend the use of portable, audible CO monitors with small gasoline- powered engines. DISTRIBUTION NIOSH, CDPHE, CPSC, OSHA, and EPA request that the information in this ALERT be brought to the attention of (1) aH employers and workers who use small gasoline-powered engines and tools in their jobs and trades (e.g., building, construction, agriculture, and maintenance and cleaning operations), (2) tool rental agencies and equipment sellers and users, (3) tool manufacturers, and (41 editors of appropriate trade journals. 12 Carbon Monoxide Poisoning ------- REFERENCES ACGIH [1992a], 1992-1993 threshold limit values for chemical substances and physical agents and biological exposure indices. Cincinnati, OH: American Conference of Gov- ernmental Industrial Hygienists. ACGIH [1992b]. Industrial ventilation—a manual of recommended practice. 21st ed^ Cincinnati, OH: American Conference of Governmental Industrial Hygienists Committee on industrial ventilation, pp. 2-1 to 2-16. ' BLS [1992a]. Census of fatal occupational injuries. Washington, DC: U S Department of Labor, Bureau of Labor Statistics. Unpublished data. BLS [1992b]. Survey of occupational injuries and illnesses. Washington DC- U S Department of Labor* Bureau of Labor Statistics. Unpublished data. CDC (Centers for Disease Control and Prevention) [1993]. Unintentional carbon monox- ide poisoning from indoor use of pressure washers—Iowa, January 1992-January 1993. CDC (Centers for Disease Control and Prevention) [1995a]. Carbon monoxide poisoning , from use of gasoline-fueled powered washers \n an underground parking garage- District of Columbia, 1994. MMWR 44(18):356-357,363-364. • < CDC (Centers for Disease Control and Prevention) [1995b]. Unintentional carbon mon- oxide poisonings in residential settings—Connecticut, November 1993-March 1994 MMWR 44(41 ):765-767. CDHS [1993]. Causes of unintentional deaths from carbon monoxide poisonings in California. Sacramento, CA: California Health Services Department. CDPHE [1996]. .Occupational carbon monoxide poisonings in Colorado. Denver, CO: Colorado Department of Public Health and Environment. Unpublished data. ' • , . ' , \ CFR. Code of Federal Regulations. Washington, DC: U.S. Government Printing Office! Office of the Federal Register. CPSC [1994]; National electronic injury surveillance system. Washington, DC: Consumer Product Safety Commission. Ehlers J [1994]. Carbon monoxide poisoning among Iowa farmers while using gasoline- powered washers—a case series. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health. Unpublished report. Carbon Monoxide Poisoning 13 ------- EPA [1991 a]. Air quality criteria for carbon monoxide. Washington, DC: U S Environ- mental Protection Agency, Office of Research and Development. Publication No EPA-600/8-90/045F. EPA [1991b]. Nonroad engine and .vehicle emission study—report. Washington. DC: U.S. Environmental Protection Agency, Office of Air and Radiation. Publication No EPA 21A-2001. . • ~ Forbes WH, Sargent F, Foughton FJW [1945]. The rate of CO uptake by normal man Am J Physiol 143:594-608. . Greife A, Goldenhar LM, Freund E, Stock A, Hornung R, Cormon C, Halperin W [1995]. Risk perception of carbon monoxide poisoning from gasoline-powered engines among midwest flood victims. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health. Unpublished report. llano A, Raffin T [1990]. Management of carbon monoxide poisoning. Chest 97:165-9. NCHS/CPSC [1992]. Death certificate file. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Center for Health Statistics, and Consumer Product Safety Commission. NIOSH [1992]. NIOSH recommendations for occupational safety and health. Compendium of policy documents and statements. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 92-100. Venable H, Wallingford K, Roberts D, Booher D £1995]. Simulated carbon monoxide exposure in an enclosed structure from a gasoline-powered pressure v/asher. Appl Occup Environ Hyg 70(7):581-584. Carbon Monoxide Poisoning ------- APPENDIX Carbon Monoxide Monitors and Detectors Detectors for carbon monoxide (CO) are manufactured and marketed for use in either the home or occupational industrial settings/The detectors for home use are devices which will sound an alarm before CO levels in the home become hazardous. There is an Underwnters Laboratories, Inc. performance standard (UL 2034) for residential CO detectors. Detectors currently available on the market are battery-powered, plug-in or hard-wired. Some models incorporate a visual display of the parts per million (ppm) level of CO present in the home. For more information on CO detectors for home use call the Consumer Product Safety Commission Hotline at 1-800-638-2772. CO detectors for use in residential settings are not designed for use in typical workplace settings. Monitoring requirements in an occupational setting are differentfrom monitoring in the home. In the workplace it is frequently necessary to monitor a worker's exposure to carbon monoxide over an entire work shift and determine the time-weighted average concentration of the exposure. It may also be necessary to have carbon monoxide monitors with alarm capabilities in the workplace. Carbon monoxide in the workplace can be detected using detector tubes, direct-reading passive badges, dosimeter tubes and direct-reading instruments. These badges, tubes, and instruments operate on a variety of pnnciples including colorimetric reaction, potentiomejry, coutometry, infrared spec- trometry, fluorescence, thermal conductivity, and heat of combustion. The direct-reading instruments are frequently equipped with audio and or visual alarms and may be used for area and cr personal exposure monitoring. Some have microprocessors and memory for stonng CO concentration readings taken during the day. It is significant to note that some of the devices mentioned for workplace CO monitoring are not capable of monitonng time-weighted averages, and not ail are equipped with alarms. The appropri- ate monitor must be chosen on an application-by-application basis. For more information on the availability of workplace CO monitors or their application, call the National Institute for Occupational Safety and Health at 1 -800-35-NIOSH (1 -800-356-4674) ^ Carbon Monoxide Poisoning 15 ------- National Institute for Occupational Safety and Health Colorado Department of Public Health and Environment U.S. Consumer Product Safety Commission Occupational Safety and Health Administration U.S. Environment Protection Agency DHHS (NIOSH) Publication No. 96-118 ------- |