ACCIDENT AND INJURY EPIDEMIOLOGY:
A TOOL FOR DETERMINING ACCIDENT
AND INJURY CAUSATION
Michael Romansky, Ph.D., J.D.
Throughout the United States every day, thousands of accidents occur in and out of the work place. Most of them are due to failure or improper interaction among equipment, people, supplies, and the environment.
An accident can be defined as any unplanned event that can cause loss of human life, injury, and/or property damage. More often than not, accidents are complex occurrences, comprised of numerous individual events requiring in-depth investigation and analysis by highly-skilled specialists seeking to determine causation. Such specialists are trained as scientists, technicians, or engineers and demonstrate expertise in areas which include, among others, the basic laws of physics, engineering mechanics, human factors and ergonomics, epidemiology, basic medical sciences, scientific safety principles, regulatory compliance, and even fundamental tort law.
The field of accident investigation and reconstruction has become exceedingly complex as man-machine systems, in particular, have become more sophisticated. Examining the interaction of man with his environment is an immense challenge for the professional to undertake. Such a person relies on scientific tools and technical knowledge to investigate, analyze, and reconstruct accidents with the purpose of developing conclusions and opinions which may ultimately be presented to a jury. In this setting, the scientist and engineer take on the role of the expert witness, proffering testimony that becomes an essential component of the judicial decision-making process in accident cases.
In addressing the causal factors that give rise to an accident, the scientist or engineer can adopt and implement, in conjunction with others, the principles and techniques of accident and injury epidemiology. Insight into the field and its application to determining accident causation can be gained from an understanding of epidemiology.
Epidemiology is a branch of medical science that deals with the incidence and control of disease in a population. In the literal sense, it is the study of "epidemics" which are usually thought of as attacking a general population at a specific time in a specific geographical area. One of the most notable examples of an epidemic is the bubonic plague in Europe in the mid-fourteenth century.
However, there are more subtle epidemics that attack a specific subgroup of people who may be spread out over time and place. In other words, the victims of the epidemic may not live in one place or at one time but have some other common characteristics, such as what job they perform in the work place. It is this aspect of epidemiology that makes it important to occupational safety. Thus, accidents resulting in amputations (finger-hand-arm) may not be a very common occurrence in any location or at any time, but when the population of only those persons who have worked with unguarded machine saws and presses is examined it becomes readily apparent after a prolonged period, that accidents resulting in upper extremity amputations can be considered an epidemic. Epidemiological studies linking upper extremity amputation accidents to unguarded machinery have led to the identification of machine hazards that are to be avoided in the interest of worker safety. Such studies are not typically performed by corporate safety personnel.
Instead they are left for the specially trained scientist or engineer to perform. The studies provide the basis for voluntary and mandatory standards and regulations, such as ANSI (American National Standards Institute) and OSHA (Occupational Safety and Health Administration), respectively, which are subsequently used in the enforcement approach. Such standards also form the underlying basis for varied legal proceedings addressing issues of compliance breaches.
Accident and injury epidemiology is the study of populations of people who have had the misfortune of being involved in a work-or non-work place mishap that causes injury.
The epidemiological approach is designed to associate various patterns of possible accident causes with the occurrence of the accident. It relies heavily on the analytical approach to accident investigation by studying and evaluating accident and injury mechanisms and analyzing statistical histories of accidents and their consequential effects. The cornerstone of the epidemiological approach is its review of accidents that have actually occurred as opposed to accidents that would likely occur in the absence of immediate action to remove a hazard.
Intrinsic to accident causation, and the very focus of the accident and injury epidemiologic approach, is its genesis: basic, indirect, and direct causes. Basic causes of accidents can usually be traced to poor or woefully inadequate safety policies, procedures, and decisions. This is particularly evident in the work place environment and ordinarily a symptom of poor or ineffective management and supervision. Unsafe conditions and unsafe acts can be categorized as indirect causes of accidents, along with personal factors such as, among other things, lack of skill and training, poor vision, or use of drugs or alcohol. Unplanned releases of energy and/or hazardous materials are direct causes of accidents resulting from unsafe acts and unsafe conditions.
In assessing accident causation, the scientist or engineer will typically focus investigative and analytical efforts on unsafe acts and unsafe conditions. This is done in response to statistical evidence which demonstrates that approximately 90 percent of industrial/work place accidents are caused by unsafe acts and unsafe conditions.
The ensuing examples of unsafe acts highlight some of the different categories of human failure to be investigated and analyzed in the search for accident causation:
- Operating machinery and equipment without qualifications or authorization
- Operating equipment at unsafe speeds
- Bypass or removal of safety devices
- Using defective equipment
- Improper repair practices on equipment
Unsafe conditions usually arise as a consequence of poor planning or an unsafe act. Some examples of unsafe conditions to be explored during an accident investigation include the following:
- Inadequate guards on machinery and equipment
- Defective tools, equipment, or supplies
- Congestion of the work place
- Fire and explosion hazards
- Poor housekeeping in the work place
It is noteworthy that unsafe acts and unsafe conditions do not cause accidents by themselves. Work place accidents are often the result of a wanting safety program, substandard management and supervision, inadequate controls, lack of knowledge, flawed assessment of hazards, or other personal factors.
Determining causation and assessing fault in work place accident cases largely rests on the probing efforts of the skilled specialist whose findings and conclusion provide the basis for expert opinion and subsequent court testimony. Whether that specialist is a scientist or engineer, determining the "how" and "why" of an accident is amenable to scientific and technical resolution using investigative and analytical pathways of accident and injury epidemiology.
Michael Romansky, Ph.D., J.D.
About the Author
FORCON Consultant - Michael Romansky, Ph.D., J.D. has an educational background that includes Industrial Engineering, Human Factors, Biomedical Engineering, and Accident and Injury Epidemiology as well as a Law Degree. His work experience includes having been a Research Safety Engineer and Forensic Scientist for the National Institute for Occupational Safety and Health. He has developed, implemented and managed safety and health compliance and training programs, conducted accident and injury investigation and reconstructions, directed and performed product liability and reliability investigations, and has provided litigation support work involving issues of vehicular and work-place accident and injury epidemiology, personal injury mechanisms, human factors engineering and ergonomics, biomechanics and physiology, and safety engineering.
