SPE International Conference on Health, Safety and Environment in Oil and Gas Exploration and Production,
12-14 April 2010,
Rio de Janeiro, Brazil
The accident triangle, developed by H.W. Heinrich in the 1930s, is a
fundamental cornerstone of safety philosophy which postulates that there is a
numerical relationship between unsafe acts, minor injuries, and major (fatal)
injuries. This principle has driven the approach and techniques used by all
companies actively engaged in reducing injuries in the workforce for over 70
All companies in the oil and gas industry have the ultimate goal of zero
injuries and, in particular, zero fatal injuries within their workforce.
Current injury trends show that the total recordable injury rate (TRIR) for a
given company can still be systematically reduced year on year if the right
commitment and focus is given to safety. This does not hold true in many cases
for the fatal accident rate (FAR) which often no longer mirrors the TRIR trend
as one would intuitively expect. This begs an answer to the question of whether
the tools and methods used to reduce fatalities are still working.
This paper demonstrates that Heinrich’s principle works only when applied to a
large number of combined hazards and activities. The paper shows that ratios
postulated by Heinrich do not work when applied to specific activities. The
result is that companies tend to over focus on the easily identifiable risks
which follow the Heinrich triangle but are often nonfatal, at the cost of
losing sight of activities that have the potential of a fatal outcome.
By drawing on the 2.3 million risk reports recorded in the health, safety, and
environment (HSE) database of an oilfield services company, the paper also
demonstrates the value of focusing on risk potential—rather than only on actual
event outcome—as a key tool for minimizing catastrophic loss. It discusses
strategies of how to specifically target and actively work on improving the FAR
as opposed to the more general TRIR.
H. W. Heinrich’s work Industrial Accident Prevention: A Scientific
Approach, first published in 1931, and the further development by Bird and
Germain in Practical Loss Control Leadership (Bird and Germain 1985) are often
considered seminal works that form the foundation for today’s implementation of
safety-management systems and behavior-based safety. One concept that has been
widely embraced from these works is the accident triangle: the hypothesis that
rather than focus on the few injuries at the top of the triangle to learn how
to avoid major and, in particular, catastrophic loss, we should focus on the
many accidents or near accidents at the bottom or base of the triangle. After
30 years or more applying these theories we should be seeing good results.
Although the industry has made great progress in reducing injuries overall and
can see the route forward for further reductions with improved implementation
of behavior-based safety, for the past 5 to 8 years we have seen that the
reduction of fatalities as measured by the FAR has slowed, stagnated, or, in
some cases, even increased. This indicates that the current strategy is
becoming less effective as we achieve ever lower FAR, and we need to develop a
new approach to continue to effectively address the low-frequency/high-impact
accidents that result in fatalities.
Our study revealed situations in which the Heinrich theory still works
effectively and those in which it is reaching its limitations and allowed us to
identify new concepts that will specifically address managing and reducing