Noise at sea: Characterization of extended shift noise exposures among U.S. Navy aircraft carrier support personnel

Abstract

The purpose of this investigation was to characterize 12-hr on-duty, 12-hr off-duty, and 24-hr noise exposures among U.S. Navy aircraft carrier support personnel. Noise dosimetry samples were collected for 47 aircraft carrier support personnel while at sea during airwing carrier qualifications. L_eq measurements during 12-hr on-duty, 12-hr off-duty, and over 24-hr periods were compared to Threshold Limit Values. Four similar exposure groups (SEGs) were created based upon departmental assignment and similarity of work tasks: (1) Administration/Religious Ministries/Legal/Training, (2) Combat Systems/Operations, (3) Medical/Dental, and (4) Supply. Equivalent sound level (Leq) measurements in decibels “A” weighted (dBA) were compared to determine significant differences between each group according to 12-hr on-duty, 12-hr off-duty, and 24-hr periods. Mean 24-hr noise levels ranged from 69–88 dBA with 22% exceeding the 80 dBA Threshold Limit Value. Twelve-hr on-duty noise levels ranged from 71–90 dBA with 17% exceeding the 83 dBA 12-hr on-duty Threshold Limit Value. Twelve-hr off-duty noise exposure ranged from 68–84 dBA with 95% exceeding the 70 dBA American Conference of Governmental Industrial Hygienists threshold classified as effective quiet to allow for temporary threshold shift recovery. Welch Analysis of Variance and Dunnett T3 post hoc tests revealed SEG 2 had significantly higher 24-hr noise exposures than SEG 3 (p = 0.019) and SEG 4 (p = 0.045). SEG 2 had significantly higher 12-hr on-duty noise exposure than SEG 3 (p = 0.030). One Way Analysis of Variance revealed no significant differences between 12-hr off-duty noise exposures according to SEG (p = .096). Some aircraft carrier support personnel had 12-hr on-duty and 24-hr noise exposures exceeding Threshold Limit Values with a large proportion exceeding the 70 dBA effective quiet limit during 12-hr off-duty periods. Results suggest personnel that are typically considered low risk for hazardous noise exposure (<85 dBA) during 8-hr shifts may have a greater risk of noise exposure when considering full 12-hr and 24-hr shifts when working and living in close proximity.

Keywords:

• 12-hr noise exposure
• 24-hr noise exposure
• auditory rest
• effective quiet
• hearing loss
• noise dosimetry

Acknowledgments

We appreciate the assistance of Colonel Mary Brueggemeyer for her helpful comments regarding research design. Special thanks to the Commanding Officer and crew of the USS GEORGE WASHINGTON for their participation in the investigation. We are especially grateful for Lt. Phong Trac, USS GEORGE WASHINGTON Assistant Safety Officer, who was instrumental in setting up the logistics prior to and during the at-sea period. Finally, we would like to thank Dr. Cara Olsen for her statistical guidance and expertise.

Disclaimer

The contents of this publication are the sole responsibility of the authors and does not necessarily reflect the views, opinions or policies of Uniformed Services University (USU), the Department of Defense (DoD), or the Department of the Navy. Mention of trade names, commercial products, or organizations does not imply endorsement by the U.S. Government.

Additional information

Funding

This research was funded by the Office of Naval Research, grant number N0001413MP20134.