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

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                              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 •  ,        -  '  ' •    '        ' '      •/'•'''•.•••-••'

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                                 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

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                         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

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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.

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  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

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  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.

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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

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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

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      • 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

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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

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  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

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       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

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  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

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        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

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        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

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                      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

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                    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

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     •  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

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      • 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

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    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

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 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

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                                 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

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 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

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