Remove or eliminate secondary factors that are under your control. Keep the work area clean and uncluttered. Control access and shut down operations when others enter the work area. This is common when operators work around powerful equipment every day and become comfortable with their ability to control the machinery. However, operators are limited by their reaction time.
Time varies by individual, and with age and physical condition.
Human reaction time is not quick enough to avoid accidents with machinery. Gravity also is faster than human reaction. For example, it is very dangerous to reach underneath the hydraulic loader arm of a skid steer loader. If the hydraulic line breaks, gravity could pull the loader bucket to the ground at a rate of about 9 feet in three-fourths of a second, and crush the extended arm of the operator. Manufacturers have built safeguards into equipment but all hazards cannot be removed.