MISHAP CAUSES, PREVENTION, AND
The Navy spends millions of dollars each year on
damage, fatalities, injuries, and occupational illnesses.
Mishaps seriously degrade operational readiness and
waste tax dollars. Preventing mishaps depends on
identifying, controlling, eliminating, and correcting
hazards. When preventive efforts fail and mishaps do
occur, investigating them thoroughly helps to determine
the causes and prevent recurrences. The lessons learned
from a mishap or near-mishap can yield valuable safety
What is a mishap? Mishap Investigation and
Reporting (OPNAVINST 5102.1C) defines a mishap
as any unplanned or unexpected event causing
personnel injury, occupational illness, death, material
loss or damage, or an explosion of any kind.
Mishaps are usually a painful experience. After
being involved in a mishap, most people look back and
say those immortal words, If only I... They then
finish the statement with had or had not. . . With that
information in mind, you should work toward making
the words If only I obsolete. How do you do that? You
cant be everywhere at the same time. To prevent
mishaps, you have to get people to think about safety.
You must promote enough interest to make people want
to perform each task safely. We assume most people
want to do their best; but remarkably, many people do
not associate best with safe. All Navy personnel must
commit themselves to think smart, think safety.
In this chapter, we discuss various statistics on
mishap causes, prevention methods, and hazard abate-
Seldom does a mishap have a simple cause. A
combination of factors, coming together under just the
right circumstances, usually cause the mishap. A
specific chain of events often leads to a mishap.
Breaking any link in that chain can usually prevent the
mishap. To prevent their recurrence, we need to know
what those events and the contributing causes were.
Normally, we divide cause factors into the following
1. Primary cause. The primary cause, also called
the immediate cause, is the actual, obvious cause of the
mishap. For example, the cause of the sailors death was
a head injury from a fall down a ladder. The primary
cause of death was the head injury.
2. Contributing causes. Contributing causes are
all the factors that made up the chain of events leading
to the primary cause. Only through investigation can we
determine these contributing causes. For example, the
primary cause of death was a head injury from a fall
down a ladder. The contributing causes could have been
worn ladder treads, a missing heel on the sailors shoe,
greasy hand rails, the sailors rushing down the ladder,
or many other causes. The primary cause alone does not
give you enough information to prevent recurrence of
Unsafe acts and conditions are known causes.
Knowing how these unsafe acts and conditions develop
will make your mishap prevention training more
You can stop mishaps by preventing or eliminating
the causes. That is why all hands, especially supervisors,
need to understand why mishaps occur. The more you
know about the causes of mishaps, the better equipped
you will be to prevent them.
A practical definition of a mishap cause is anything
and everything that has contributed to a mishap. That
includes the primary and the contributing causes. The
purpose of this broad interpretation of a mishap cause is
to encourage you to adopt a broad and open approach
when identifying the cause of a mishap. Thus, do not
focus all your attention on the mishap alone. Investigate
everything that leads to the mishap both directly and
indirectly before determining the probable cause or
causes. We categorize causes as follows:
Maintenance and support factors
Administrative and supervisory factors
Material failures or malfunctions