Aircraft Carrier Personnel Mishap and Injury Rates during Deployment

Military Medicine, May 2005 by Parrish, Douglas K, Olsen, Cara H, Thomas, Richard J

This cohort study assessed all reported injuries experienced by the personnel of a U.S. Navy aircraft carrier during two consecutive 6-month deployments. These nondisease injury cases were collected by the ship's Safety Department from ship's Medical Department reports and showed 291 total injuries (3.05 injuries per 10,000 person-days) and 412 total injuries (4.39 injuries per 10,000 person-days) among 5,101 personnel during two cruises, slightly higher than the recordable mishap rate for general U.S. industry (which uses a different metric). Junior personnel experienced one-half of the mishaps but represented only 31% of the manpower. Slips, trips, and falls were the most common causes of accidents on the ship, similar to general industry. The incidence densities and causes reported should be similar to and representative of those for other large deck ships in the U.S. Navy and can be used in developing risk-reduction strategies for targeted populations, to meet the Secretary of Defense requirement to reduce injuries by 50% in the next 2 years.

Introduction

Aircraft carriers in the U.S. Navy are the largest warships in the world.1 With their embarked air wings, carriers are deployed worldwide to serve a variety of roles in peacetime and during global crises. Carriers are manned by >5,000 personnel, with the exact complement depending on the class of ship and specific employment. There are hundreds of details and jobs associated with operating this small city 24 hours per day, 7 days per week, at sea, such as food preparation, production of electricity, steam, and fresh water, propulsion and auxiliary systems, and operation and maintenance of all of the weapons, communications, navigation, and assorted systems, as well as the numerous complex aspects of flight operations.

In general U.S. industry, it is estimated that >6 million workers are injured each year, with insurance, health care, lost time, and worker replacement and retraining costs of $121 billion.2 The military has the potential for similar injuries but has a much smaller manpower pool to draw from and a longer logistics tail during deployments. Military training, recreational, and work injuries are the most significant source of loss of manpower, hospitalizations, and reduction of readiness.3

During the period of 1980-1993, active duty Navy personnel suffered 4,607 deaths attributable to unintentional injuries (59.4 deaths per 100,000 population), with an all-cause mortality total of 7,485 (96.5 deaths per 100,000 population). Unintentional injuries include disease, illness, suicide, homicide, deaths attributable to hostile action, and miscellaneous causes.4 As of October 3, 2003, there were 383,890 active duty personnel in the Navy, i.e., 55,317 officers and 328,573 enlisted personnel. There were also 185,550 Navy Department civilian employees and 152,464 Ready Reservists.5 The average age of the enlisted personnel in the Navy is 27 years (51% of all enlisted personnel and 44% of the total force are below this age). On average, officers are approximately one decade older (35 years of age) than enlisted personnel6 (D. Thao, unpublished data).

This is an analysis of a U.S. Navy aircraft carrier's mishap and injury database covering two 6-month deployments to the same general operating areas, in 1999 and 2001. The purpose was to determine trends in injury types, causes, and basic demographic features. The information described here may assist U.S. Navy leaders and safety managers in developing risk-reduction strategies. The Secretary of Defense set an ambitious goal for all U.S. military services to reduce all-cause mishap and accident rates by 50% in the next 2 years.7 President George W. Bush followed up the Department of Defense goal with a similar goal for all U.S. federal agencies to reduce accidents and injuries by implementing the Safety, Health, and Return-to-Employment initiative. President Bush established four specific workplace goals, each of which is relevant to this research and discussion, namely, lower injury/illness rates, lower lost-time injury/illness rates, timely reporting of injuries/illnesses, and fewer lost days from work injuries and illnesses.8

After establishment of the Occupational Safety and Health Act of 1970, the U.S. military adopted many safety and injury prevention programs similar to those of the civilian workforce. Several U.S. presidential executive orders later broadened the requirements for the military to more fully comply with all aspects of the Occupational Safety and Health Act. The Navy Occupational Safety and Health Program does include numerous points that are unique to the Navy operational environment.9 The U.S. Naval Safety Center is charged with overall safety program oversight for the Navy.10 The Safety Center wrote specific program instructions for the Navy, including ashore (OPNAV5100.23F) and afloat (OPNAV5100.19D, CH-1) Navy Occupational Safety and Health Program manuals.9

New U.S. Naval Safety Center reporting criteria that are not reflected in this study went into effect in October 2002, requiring the reporting of all injuries that cause ≥1 lost workdays.9 Until the start of 2003, most injuries were never reported or recorded off ship unless they met certain criteria, as defined by the Naval Safety Center. Direct comparison of the incidence densities of total injuries between ships is impossible even today, because of the lack of a central reporting repository that tracks all injuries, including non-lost time cases. In the past, direct comparisons were normally made only for reportable categories (e.g., class A mishap fatality rates).11