“Proximate Causes and Subcauses (Personal).— In connection with the unsafe acts of persons (which are the direct causes of the majority of accidents) the immediately preceding subcauses are of great value in determining the most practical remedy. For example, it is not always enough to know merely that a machine operator oiled his machine while it was in motion. The reason why he acted unsafely is often of vital significance. He may have been required to do so by the foreman. Enforced time schedules may have prevented him from taking safer action. He may not have realized the danger, may have been physically or mentally unsuited or may have willfully disregarded instructions.”
Source: Industrial Accident Prevention – A Scientific Approach, H. W. Heinrich, Assistant Superintendent Engineering and Inspection Division, The Travelers Insurance Company, 1941
