Suffocations in grain bins - Minnesota, 1992-1995

Morbidity and Mortality Weekly Report, Oct 4, 1996

Suffocation in flowing grain is the most common cause of death associated with grain storage structures in the United States (1,2): during 1985-1989, suffocation accounted for 49 grain- and silage-handling-associated fatalities (3). During 1992-1995, nine persons in Minnesota died in separate incidents from asphyxiation after becoming engulfed in flowing grain within a grain storage structure (Figure 1). The Minnesota Fatality Assessment and Control Evaluation program (FACE), a program sponsored by CDC's National Institute for Occupational Safety and Health (NIOSH)(*), was notified of the incidents by the state Occupational Safety and Health Administration (MN-OSHA), Minnesota Extension Services, and a newspaper clipping service. This report describes the investigation of three of these incidents by FACE, summarizes surveillance for grain bin suffocations during 1992-1995, and provides recommendations to prevent suffocations associated with grain storage bins.

Case Reports

Incident 1. On December 17, 1992, a 32-year-old man working at a commercial grain elevator became engulfed in 60,000 bushels (1000 bushels=1240 cubic feet) of corn that were being emptied from the bottom of the bin by a grain auger[dagger]. He had entered the bin through the roof hatch to dislodge crusted grain. Co-workers called rescue personnel when he was noted to be absent, and holes were cut in the grain bin walls to accelerate emptying of the bin. The worker's body was recovered near the center of the bin 8 hours after the incident. Employees reported the man had been warned not to enter the bin. Confined-space safety measures, including warning signs on the bin, were in place.

Incident 2. On September 11, 1994, a 44-year-old farmer was asphyxiated after he became immersed in 6000 bushels of corn being removed from a self-unloading bin. He had entered the bin through the roof hatch to dislodge crusted grain that had blocked the auger intake. Several minutes later, a co-worker noted he was missing and shut off the auger. He was pulled out of the grain from above by family members, resuscitation efforts were initiated, and emergency personnel were called. He was transported to a local hospital and pronounced dead approximately 1 hour after having entered the bin.

Incident 3. On July 11, 1995, a 13-year-old boy became submerged in 2500 bushels of corn in a grain bin as the grain was being loaded into a truck by a portable auger. He had been seen observing the unloading process from a point near the roof opening of the bin; his father, who was working near the truck below, noticed he was no longer visible. Rescue personnel cut holes in the lower portion of the bin to allow the grain to spill out. The boy was then extracted and transported to the hospital but died on July 13.

Surveillance for Suffocations Associated with Grain Bins

Since 1992 the Minnesota Department of Health has compiled surveillance and field investigation data about selected work-related agricultural fatalities through FACE. FACE collects epidemiologic data from multiple sources, including police reports, on-site investigations, and MN-OSHA, regarding selected occupational fatalities and develops and disseminates prevention recommendations to address identified risks.

During 1992-1995, nine persons in Minnesota suffocated in grain bins. All nine were males aged 13-71 years (mean: 36 years). Six of the incidents occurred on family-owned farms, and three occurred at commercial grain elevators. Grain was being unloaded or removed from the involved storage bins in eight incidents and was being added to the bin in one case. The amount of grain involved in the incidents ranged from 600 to 60,000 bushels, and grain types included corn (six incidents), soy-beans (two), and wheat (one). Because none of the engulfments and subsequent suffocations were witnessed, recognition of most cases and initiation of rescue efforts were delayed. Reported by: GL Wahl, MS, SE Folken, DJ Boyle, DVM, DL Parker, MD, Minnesota Dept of Health. Div of Safety Research, National Institute for Occupational Safety and Health, CDC.

Editorial Note: The findings in this report indicate that suffocations in grain bins are a continuing source of preventable occupationally related deaths among workers in the agriculture industry. CDC's National Traumatic Occupational Fatalities (NTOF) surveillance data from 1980 through 1992 contain death-certificate reports of 88 farm workers killed by engulfment in grain or other agriculture produce stored in bins or silos, and the Census of Fatal Occupational injuries (CFOI) (maintained by the Bureau of Labor Statistics) contain an additional 33 reports of deaths associated with engulfment in grain bins for 1993 through 1994 (NIOSH, unpublished data, 1996)[subsection]. No reliable estimates are available for nonfatal incidents.

Most grain storage bins are round, flat-bottomed structures with capacities of 20,000-100,000 bushels of grain (1,2); many older bins on farms are smaller and may hold [less than or equal to]5000 bushels (Figure 1). Most bins on farms are filled through a hatch in the roof and emptied through a hole in the center of the floor (4). The mechanical augers used to unload bins can move grain at rates of up to 3000 cubic feet per hour (1,2), and a person can become completely submerged in the flowing grain in 8 seconds (1,2). Because grain bin interior doors are designed to open inward, side doors cannot be opened during rescue efforts when grain levels are above the entry doors.