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`
`Fatalities Attributed to Entering Manure Waste Pits -- Minnesota, 1992
`
`
`
`Weekly
`May 07, 1993 / 42(17);325-329
`
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`
`Fatalities Attributed to Entering Manure Waste
`Pits -- Minnesota, 1992
`
`In August 1992, four farm workers in Minnesota died in two separate incidents after entering manure
`waste pits: two were poisoned by hydrogen sulfide gas, and two were asphyxiated. The Minnesota Fatality
`Assessment and Control Evaluation (FACE) program was notified of the incidents by the state
`Occupational Safety and Health Administration and the Minnesota Farming Health Project, respectively.
`This report summarizes the investigations of these two incidents by the Minnesota FACE program and
`CDC's National Institute for Occupational Safety and Health (NIOSH) FACE personnel. Incident 1
`
`On August 8, a 27-year-old employee of a hog farm and his 46-year-old uncle, who co-owned the farm,
`died after entering an outdoor manure pit. On August 7, the farm employee and a coworker had attempted
`to pump out the 12-foot-deep, 49-inch diameter pit but could not because of a clogged pump intake in the
`pit. When they attempted to extract the pump from the pit with an attached 1/4 inch wire rope, the rope
`broke. The following morning, although cautioned by his coworker about the possible presence of
`poisonous gases in the manure pit, the employee indicated he had entered the pit in the past without
`trouble and descended a ladder 9 feet into the pit to attach a new rope to the pump. While attempting to
`attach the rope, he was overcome and fell off the ladder into the pit. The coworker summoned rescue
`personnel and the farm co-owner.
`
`Although the co-owner also was warned of possible poisonous gases in the pit, and despite efforts to
`physically restrain him, he descended the ladder into the pit 10 minutes after the nephew had entered; he
`also was overcome and fell into the pit. Twenty minutes after the initial entry, both men were removed
`from the pit by rescue personnel equipped with appropriate respiratory protection (self-contained
`breathing apparatus). Cardiopulmonary resuscitation was initiated, and the men were transported to a
`hospital where both were pronounced dead on arrival. The death certificates listed hydrogen sulfide
`poisoning as the cause of death for both men.
`
`Atmospheric readings in the pit on September 2 during the FACE investigation detected no measurable
`levels of hydrogen sulfide or methane and an oxygen level of 20.4% (normal: 19.5%-21.0%). However,
`the weather conditions on the day the readings were taken (cool and breezy) differed from those on the
`day of the incident (hot and humid). Incident 2
`
`On August 11, a 43-year-old dairy farm owner and his 23-year-old son died from asphyxiation after
`entering one of two adjacent manure waste pits underneath a barn. The 8-foot-deep pits were connected by
`a tunnel so that both could be pumped from one pit. Although the incident was unwitnessed, an
`investigation of physical evidence and interviews with rescue personnel suggested the following series of
`events: The two men were using a pump located outside the barn to pump manure from the pits into the
`tank of a manure spreader. They pumped the manure from the first pit but apparently were unable to pump
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`Fatalities Attributed to Entering Manure Waste Pits -- Minnesota, 1992
`11/22/22, 12:08 PM
`manure from the adjacent pit because of an obstruction in the connecting tunnel. The father then removed
`a steel grate cover, descended a ladder into the nearly empty pit, and was overcome as he began to clear
`the tunnel obstruction. His son was found lying on top of him, apparently overcome during a rescue
`attempt. The men were discovered approximately 2 1/2 hours later, based on the coroner's estimated time
`of death for the men.
`
`The men were removed from the manure pit by rescue personnel equipped with appropriate respiratory
`protection and were pronounced dead at the scene by the coroner. The coroner attributed the cause of
`death for both men to asphyxiation due to hypoxia.
`
`Reported by: G Madery, MS, D Parker, MD, Section of Chronic Disease and Environmental
`Epidemiology, Minnesota Dept of Health; J Shutske, PhD, Dept of Agricultural Engineering, Univ of
`Minnesota, St. Paul. Div of Safety Research, National Institute for Occupational Safety and Health, CDC.
`
`Editorial Note
`
`Editorial Note: A manure waste pit, by its design, meets the criteria established by NIOSH for a confined
`space (i.e., a space with limited openings for entry and exit, with unfavorable natural ventilation that could
`contain or produce dangerous air contaminants, and that is not intended for continuous worker occupancy
`{1}). The fermentation and decomposition of waste can create oxygen-deficient, toxic, and/or explosive
`atmospheres; the anaerobic bacterial action that decomposes the manure can generate methane, hydrogen
`sulfide, carbon dioxide, and ammonia. Death can result either from oxygen deficiency or from the direct
`toxic effects of these gases (2).
`
`Sources of data to study work-related confined space fatalities, such as those described in this report,
`include the FACE program and the National Traumatic Occupational Fatality (NTOF) surveillance
`system. The FACE program collects epidemiologic data from the investigation of selected occupational
`fatalities, identifies factors that might increase the risk for work-related fatal injury, and develops and
`disseminates preventive recommendations to address these risks. Minnesota is one of 12 states * that
`receive funding from NIOSH for state FACE programs. NIOSH's Division of Safety Research monitors
`overall numbers of acute traumatic occupational deaths in the United States using the NTOF surveillance
`system, a census of fatal work-related injuries based on death certificate information collected from the 52
`U.S. vital statistics reporting units ** (3).
`
`As described in this report, incidents involving entry into confined spaces often result in multiple fatalities
`when coworkers or others die during attempts to rescue initial victims; on farms these are often family
`members. For 1980-1989, the NTOF surveillance system identified a yearly average of 89 occupational
`deaths that occurred in any type of confined space. Of these, approximately 20 (22%) occurred each year
`during rescue attempts (3). Similarly, from 1982 through 1992, as part of the FACE program, NIOSH
`personnel investigated 68 confined-space incidents that resulted in 104 fatalities; of these, 36 (35%) were
`workers who died during rescue attempts (4), and two were public safety personnel. Persons who died
`during rescue attempts were more likely to be coworkers than public safety or emergency medical service
`(EMS) personnel (5). Asphyxiation by atmospheric hazards was the primary cause of rescuer death,
`although the exact mechanism of death is often difficult to determine. In general, findings of autopsies
`performed on manure pit fatality victims are nonspecific and do not identify the specific gas(es) likely to
`have caused death.
`
`Rescue operations in confined spaces present unique hazards, and proper training and specialized
`equipment are required to protect rescuers from injury and death. Public safety and EMS personnel should
`be able to recognize confined-space hazards and should be familiar with the use of proper rescue
`equipment and techniques (1,6- 8 ).
`
`In the two incidents described in this report and in similar incidents investigated by NIOSH (9,10), hot,
`humid weather may have contributed to the generation of gases in the manure pits, an association also
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`Bazooka v. Nuhn - IPR2024-00098
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`Fatalities Attributed to Entering Manure Waste Pits -- Minnesota, 1992
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`suggested by NTOF data (Figure 1). The 22 deaths during 1980-1989 identified by NTOF data *** that
`were attributed to asphyxiation of workers in manure pits or similar waste tanks occurred in 13 states ****
`during April through September. Although manure pit gases are potentially present at all times, farm
`workers should be particularly aware of the hazards of entering manure pits during summer months, when
`conditions are optimal for the microbial activity that can result in increased gas generation. Manure pits
`that have previously been entered without incident may become toxic and/or oxygen deficient, and this
`change would not be detected without testing the atmosphere of the pit.
`
`To prevent serious or fatal exposures such as those described in this report, NIOSH recommends that
`manure waste pits be identified as confined spaces and that warning signs be posted at all entrances to
`these pits. Farm workers should be instructed never to enter manure waste pits, even to attempt a rescue,
`unless appropriate safety measures are employed; these include the use of appropriate respiratory
`protection and adherence to safe confined-space entry procedures. In addition, where possible, manure
`waste systems should be designed to provide access to all serviceable parts from outside the pit.
`Manufacturers of equipment designed for use in manure waste systems should include warnings of the
`potential hazards associated with worker entry into manure waste pits.
`
`References
`
`1. NIOSH. Criteria for a recommended standard: working in confined spaces. Cincinnati: US
`Department of Health, Education, and Welfare, Public Health Service, CDC, 1979; DHEW
`publication no. (NIOSH)80-106.
`
`2. Donham KJ. Livestock confinement. In: Parmeggiani L, ed. Encyclopedia of occupational health
`and safety. 3rd ed. Vol 2. Geneva: International Labor Organization, 1983:1239-41.
`
`3. NIOSH. National Traumatic Occupational Fatality database {Machine-readable datatape}, 1980-
`1989. Morgantown, West Virginia: US Department of Health and Human Services, Public Health
`Service, CDC, 1992.
`
`4. NIOSH. Fatality Assessment and Control Evaluation program database {Machine-readable
`datatape}, 1982-1992. Morgantown, West Virginia: US Department of Health and Human Services,
`Public Health Service, CDC, 1992.
`
`5. Suruda A, Pettit T, Noonan G, Ronk R. Deadly rescue: the confined space hazard. Journal of
`Hazardous Materials (in press).
`
`6. NIOSH. NIOSH alert: request for assistance in preventing deaths of farm workers in manure pits.
`Cincinnati: US Department of Health and Human Services, Public Health Service, CDC, 1989;
`DHHS publication no. (NIOSH)90-103.
`
`7. NIOSH. NIOSH alert: request for assistance in preventing occupational fatalities in confined
`spaces. Cincinnati: US Department of Health and Human Services, Public Health Service, CDC,
`1986; DHHS publication no. (NIOSH)86-110.
`
`8. NIOSH. A guide to safety in confined spaces. Cincinnati: US Department of Health and Human
`Services, Public Health Service, CDC, 1986; DHHS publication no. (NIOSH)87-113.
`
`9. Division of Safety Research, NIOSH. Two farm laborers die in oxygen-deficient manure pit.
`Morgantown, West Virginia: US Department of Health and Human Services, Public Health Service,
`CDC, 1989; FACE report no. 89-44.
`
`10. Division of Safety Research, NIOSH. Five family members die after entering manure waste pit on a
`dairy farm. Morgantown, West Virginia: US Department of Health and Human Services, Public
`Health Service, CDC, 1989; FACE report no. 89-46.
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`Bazooka v. Nuhn - IPR2024-00098
`Page 3 of 4
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`0
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`Fatalities Attributed to Entering Manure Waste Pits -- Minnesota, 1992
`Alaska, California, Colorado, Georgia, Indiana, Iowa, Massachusetts, Minnesota, Missouri,
`New Jersey, Wisconsin, and Wyoming. ** The 50 states, Washington, D.C., and New York
`City. *** Because NTOF data include only deaths of workers aged greater than or equal to 16
`years that are clearly identified as being work related and because death certificates often do
`not include sufficient information to identify specifically deaths occurring in manure pits, this
`enumeration may underestimate asphyxiation fatalities that occurred during this period
`among those working in manure pits. **** Illinois, Indiana, Iowa, Kansas, Michigan,
`Minnesota, Nebraska, New York, Ohio, Pennsylvania, South Dakota, Tennessee, and Utah.
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`Exhibit 1046
`Bazooka v. Nuhn - IPR2024-00098
`Page 4 of 4
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