The accident triangle, also known as Heinrich's triangle or Bird's triangle, is a theory of industrial accident prevention. It shows a relationship between serious accidents, minor accidents and near misses. This idea proposes that if the number of minor accidents is reduced then there will be a corresponding fall in the number of serious accidents. The triangle was first proposed by Herbert William Heinrich in 1931 and has since been updated and expanded upon by other writers, notably Frank E. Bird. It is often shown pictorially as a triangle or pyramid and has been described as a cornerstone of 20th century workplace health and safety philosophy. In recent times it has come under criticism over the values allocated to each category of accident and for focusing only on the reduction in minor injuries.
The triangle shows a relationship between the number of accidents resulting in serious injury, minor injuries or no injuries. The relationship was first proposed in 1931 by Herbert William Heinrich in his Industrial Accident Prevention: A Scientific Approach. [1] Heinrich was a pioneer in the field of workplace health and safety. He worked as an assistant superintendent for an insurance company and wanted to reduce the number of serious industrial accidents. He commenced a study of more than 75,000 accident reports from the insurance company's files as well as records held by individual industry sites. [2] From this data he proposed a relationship of one major injury accident to 29 minor injury accidents, to 300 no-injury accidents. He drew the conclusion that, by reducing the number of minor accidents, industrial companies would see a correlating fall in the number of major accidents. [2] [1] The relationship is often shown pictorially in the form of a triangle or pyramid. The pyramid allows individuals to narrow down the root cause and eliminate or control the hazard or cause. [3] The triangle was widely used in industrial health and safety programs over the following 80 years and was described as a cornerstone of health and safety philosophy. [2] [1] Heinrich's theory also suggested that 88% of all accidents were caused by a human decision to carry out an unsafe act. [2]
The theory was developed further by Frank E Bird in 1966 based on the analysis of 1.7 million accident reports from almost 300 companies. He produced an amended triangle that showed a relationship of one serious injury accident to 10 minor injury (first aid only) accidents, to 30 damage causing accidents, to 600 near misses. However, one could assume that not all minor injuries and near misses will be reported, which will result in some fault of the triangle. [4] The numbers used by Bird were confirmed by a 1974 study by A. D. Swain, entitled The Human Element in Systems Safety. [5] The theory was later expanded upon by Bird and Germain in 1985's Practical Loss Control Leadership. [1] Bird showed a relationship between the number of reported near misses and the number of major accidents and claimed that the majority of accidents could be predicted and prevented by an appropriate intervention. [6]
Heinrich's triangle had a significant impact on health and safety culture in the 20th century but has recently been criticized. [2] Some of this criticism regards to the exact figures used in the relationship. A 2010 report relating to the oil and gas industry showed that the original values held true only when applied to a large dataset and a broad range of activities. [1] A 1991 study showed that in confined spaces the relationship was significantly different: 1.2 minor injuries for each serious injury or death. [7] A broad study of UK accident data in the mid-1990s showed a relationship of 1 fatality to 207 major injuries, to 1,402 injuries causing three or more days lost time injuries, to 2,754 minor injuries. [8] Heinrich's original files have since been lost so his accident figures cannot be proven. [2]
W. Edwards Deming stated that Heinrich's theory attributing human action as the cause of most accidents in the workplace was incorrect and it was, in fact, poor management systems that caused the majority of accidents. [2] There has also been criticism of the triangle for focusing attention on the reduction of minor accidents. It has been claimed that this has led to workplace supervisors to ignore more serious but less likely risks when planning works in order to focus on reducing the likelihood of more common but less serious risks. The 2010 oil and gas study claimed that this attitude had led to a halt in the reduction of fatalities in that industry in the preceding five to eight years, despite a significant reduction in minor accidents. [1]
The Occupational Safety and Health Administration is a regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. The United States Congress established the agency under the Occupational Safety and Health Act, which President Richard M. Nixon signed into law on December 29, 1970. OSHA's mission is to "assure safe and healthy working conditions for working men and women by setting and enforcing standards and by providing training, outreach, education, and assistance." The agency is also charged with enforcing a variety of whistleblower statutes and regulations. OSHA's workplace safety inspections have been shown to reduce injury rates and injury costs without adverse effects on employment, sales, credit ratings, or firm survival.
A work accident, workplace accident, occupational accident, or accident at work is a "discrete occurrence in the course of work" leading to physical or mental occupational injury. According to the International Labour Organization (ILO), more than 337 million accidents happen on the job each year, resulting, together with occupational diseases, in more than 2.3 million deaths annually.
Risk compensation is a theory which suggests that people typically adjust their behavior in response to perceived levels of risk, becoming more careful where they sense greater risk and less careful if they feel more protected. Although usually small in comparison to the fundamental benefits of safety interventions, it may result in a lower net benefit than expected or even higher risks.
Safety in numbers is the hypothesis that, by being part of a large physical group or mass, an individual is less likely to be the victim of a mishap, accident, attack, or other bad event. Some related theories also argue that mass behaviour can reduce accident risks, such as in traffic safety – in this case, the safety effect creates an actual reduction of danger, rather than just a redistribution over a larger group.
Safety culture is the element of organizational culture which is concerned with the maintenance of safety and compliance with safety standards. It is informed by the organization's leadership and the beliefs, perceptions and values that employees share in relation to risks within the organization, workplace or community. Safety culture has been described in a variety of ways: notably, the National Academies of Science and the Association of Land Grant and Public Universities have published summaries on this topic in 2014 and 2016.
A near miss, near death, near hit, close call is an unplanned event that has the potential to cause, but does not actually result in human injury, environmental or equipment damage, or an interruption to normal operation.
Musculoskeletal disorders (MSDs) are injuries or pain in the human musculoskeletal system, including the joints, ligaments, muscles, nerves, tendons, and structures that support limbs, neck and back. MSDs can arise from a sudden exertion, or they can arise from making the same motions repeatedly, or from repeated exposure to force, vibration, or awkward posture. Injuries and pain in the musculoskeletal system caused by acute traumatic events like a car accident or fall are not considered musculoskeletal disorders. MSDs can affect many different parts of the body including upper and lower back, neck, shoulders and extremities. Examples of MSDs include carpal tunnel syndrome, epicondylitis, tendinitis, back pain, tension neck syndrome, and hand-arm vibration syndrome.
Herbert William Heinrich was an American industrial safety pioneer from the 1930s.
Injury prevention is an effort to prevent or reduce the severity of bodily injuries caused by external mechanisms, such as accidents, before they occur. Injury prevention is a component of safety and public health, and its goal is to improve the health of the population by preventing injuries and hence improving quality of life. Among laypersons, the term "accidental injury" is often used. However, "accidental" implies the causes of injuries are random in nature. Researchers prefer the term "unintentional injury" to refer to injuries that are nonvolitional but often preventable. Data from the U.S. Centers for Disease Control show that unintentional injuries are a significant public health concern: they are by far the leading cause of death from ages 1 through 44. During these years, unintentional injuries account for more deaths than the next three leading causes of death combined. Unintentional injuries also account for the top ten sources of nonfatal emergency room visits for persons up to age 9 and nine of the top ten sources of nonfatal emergency room visits for persons over the age of 9.
The Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 2013, often known by the acronym RIDDOR, is a 2013 statutory instrument of the Parliament of the United Kingdom. It regulates the statutory obligation to report deaths, injuries, diseases and "dangerous occurrences", including near misses, that take place at work or in connection with work.
Occupational health psychology (OHP) is an interdisciplinary area of psychology that is concerned with the health and safety of workers. OHP addresses a number of major topic areas including the impact of occupational stressors on physical and mental health, the impact of involuntary unemployment on physical and mental health, work-family balance, workplace violence and other forms of mistreatment, psychosocial workplace factors that affect accident risk and safety, and interventions designed to improve and/or protect worker health. Although OHP emerged from two distinct disciplines within applied psychology, namely, health psychology and industrial and organizational psychology, for a long time the psychology establishment, including leaders of industrial/organizational psychology, rarely dealt with occupational stress and employee health, creating a need for the emergence of OHP. OHP has also been informed by other disciplines, including occupational medicine, sociology, industrial engineering, and economics, as well as preventive medicine and public health. OHP is thus concerned with the relationship of psychosocial workplace factors to the development, maintenance, and promotion of workers' health and that of their families. The World Health Organization and the International Labour Organization estimate that exposure to long working hours causes an estimated 745,000 workers to die from ischemic heart disease and stroke in 2016, mediated by occupational stress.
A traffic collision, also known as a motor vehicle collision, or car crash, occurs when a vehicle collides with another vehicle, pedestrian, animal, road debris, or other moving or stationary obstruction, such as a tree, pole or building. Traffic collisions often result in injury, disability, death, and property damage as well as financial costs to both society and the individuals involved. Road transport is statistically the most dangerous situation people deal with on a daily basis, but casualty figures from such incidents attract less media attention than other, less frequent types of tragedy. The commonly used term car accident is increasingly falling out of favor with many government departments and organizations, with the Associated Press style guide recommending caution before using the term. Some collisions are intentional vehicle-ramming attacks, staged crashes, vehicular homicide or vehicular suicide.
Occupational stress is psychological stress related to one's job. Occupational stress refers to a chronic condition. Occupational stress can be managed by understanding what the stressful conditions at work are and taking steps to remediate those conditions. Occupational stress can occur when workers do not feel supported by supervisors or coworkers, feel as if they have little control over the work they perform, or find that their efforts on the job are incommensurate with the job's rewards. Occupational stress is a concern for both employees and employers because stressful job conditions are related to employees' emotional well-being, physical health, and job performance. The World Health Organization and the International Labour Organization conducted a study. The results showed that exposure to long working hours, operates through increased psycho-social occupational stress. It is the occupational risk factor with the largest attributable burden of disease, according to these official estimates causing an estimated 745,000 workers to die from ischemic heart disease and stroke events in 2016.
A physical hazard is an agent, factor or circumstance that can cause harm with contact. They can be classified as type of occupational hazard or environmental hazard. Physical hazards include ergonomic hazards, radiation, heat and cold stress, vibration hazards, and noise hazards. Engineering controls are often used to mitigate physical hazards.
An accident is an unintended, normally unwanted event that was not directly caused by humans. The term accident implies that nobody should be blamed, but the event may have been caused by unrecognized or unaddressed risks. Most researchers who study unintentional injury avoid using the term accident and focus on factors that increase risk of severe injury and that reduce injury incidence and severity. For example, when a tree falls down during a wind storm, its fall may not have been caused by humans, but the tree's type, size, health, location, or improper maintenance may have contributed to the result. Most car wrecks are not true accidents; however, English speakers started using that word in the mid-20th century as a result of media manipulation by the US automobile industry.
Occupational safety and health (OSH) or occupational health and safety (OHS) is a multidisciplinary field concerned with the safety, health, and welfare of people at work. OSH is related to the fields of occupational medicine and occupational hygiene and aligns with workplace health promotion initiatives. OSH also protects all the general public who may be affected by the occupational environment.
A psychosocial hazard or work stressor is any occupational hazard related to the way work is designed, organized and managed, as well as the economic and social contexts of work. Unlike the other three categories of occupational hazard, they do not arise from a physical substance, object, or hazardous energy.
Workplace robotics safety is an aspect of occupational safety and health when robots are used in the workplace. This includes traditional industrial robots as well as emerging technologies such as drone aircraft and wearable robotic exoskeletons. Types of accidents include collisions, crushing, and injuries from mechanical parts. Hazard controls include physical barriers, good work practices, and proper maintenance.
An explosion at the ARCO Chemical (ACC) Channelview, Texas petrochemical plant killed 17 people and injured five others on July 5, 1990. It was one of the deadliest industrial disasters in the history of the Greater Houston area.
Psychosocial safety climate (PSC) is a term used in organisational psychology that refers to the shared belief held by workers that their psychological health and safety is protected and supported by senior management. PSC builds on other work stress theories and concerns the corporate climate for worker psychological health and safety. Studies have found that a favourable PSC is associated with low rates of absenteeism and high productivity, while a poor climate is linked to high levels of workplace stress and job dissatisfaction. PSC can be promoted by organisational practices, policies and procedures that prioritise the psychosocial safety and wellbeing of workers. The theory has implications for the design of workplaces for the best possible outcomes for both workers and management.