Ratio of Non-Fatal to Fatal Operator Injuries for Overturns of Farm Tractors without Rollover Protective Structures

The U.S. Bureau of Labor Statistics and National Safety Council monitor nationally and report annually operator fatalities that result from farm tractor overturns. Much less is known, however, about the prevalence of non-fatal injuries to operators during tractor overturns. This study had four objectives:

  1. Calculate the ratio of non-fatal injury outcomes to fatal outcomes for operators who overturn non-ROPS tractors;
  2. Report the extent of medical care the operators received
  3. Examine the distribution of operators’ days of work lost (temporary disability) by medical care categories
  4. Examine the frequency and distribution of permanent disability across medical care categories.

The study analyzed data from the 40-item Kentucky Tractor Overturn Survey (KYTOS) administered to a statewide 8% random sample of Kentucky’s total farm population. The sample was stratified proportional to the number of farms in each of Kentucky’s six agricultural districts and also by annual farm income in each district. The 6,063 completed telephone interviews represent a 79% response rate.

The farms surveyed reported a total of 443 non-ROPS tractor overturns. Of these, 131 resulted in operator injury. (In 312 cases the operator was not injured.) Among the 131 injuries, 24 were fatal. A total of 107 overturn injuries were non-fatal (107 nonfatal/24 fatal = 4.6). Of the 107 non-fatal injury cases, 19 injured operators did not receive medical treatment (19/24 = 0.79), while 88 cases were treated at a clinic or hospital ED (88/24 = 3.67). Of the 88 cases seen at a clinic or hospital ED, 64 were hospitalized (64/24 = 2.67). Of the 64 non-fatal hospitalized cases, 14 were permanently disabled (14/24 = 0.58). These ratios are corrected for nesting of individual overturn injury cases within multiple categories. Each fatal and non-fatal injury case is counted only once.

Medical care received did not always match injury severity: Of the 19 farmers injured who did not receive medical care, 7 were temporarily disabled and one permanently fully disabled. For the 24 who were outpatients, 3 were permanently disabled, while 10 of the 64 hospital admissions were permanently disabled. Total days of farm work lost summed across all 107 non-fatal injury cases was 7,479 including days in hospital, not including cases with work days lost > 365 days or cases were work days lost were not reported.

This study’s estimates of the ratios of non-fatal to fatal injury outcomes to operators who overturn tractors make it possible to calculate the costs associated with non-fatal injuries to operators who overturn non-ROPS tractors, a specific aim listed in the 2004 National Agricultural Tractor Safety Initiative. Previous injury-cost analyses have not included detailed data about non-fatal injury outcomes and medical care for a population-based random sample of farmers involved in overturns of non-ROPS tractors. This project provides more complete and accurate information about the cost of tractor-related injury events and the return on investment in measures designed to avert them.

Further Reading:

Cole HP, Myers ML, Westneat SC. Frequency and severity of injuries to operators during overturns of farm tractors. J Agric Saf Health. 2006;12(2):127-38. PMID: 16724789

Cole HP, Westneat SC, Myers ML. Ratio of fatal to non-fatal operator injuries for overturns of farm tractors without ROPS. Technical Paper 06-02 in Proceedings of the Annual Meeting of the National Institute for Farm Safety; Sheboygan, WI; 2006 Jun 25–30.