INTRODUCTION 



Increasing noise levels are the result of advanced technologies and rapidly growing 

 human populations. Noise is a by-product of almost every aspect of human activity. Areas 

 previously thought to be remote and nonpoUuted by noise may soon have noise pollution 

 from a variety of sources. 



Offshore petroleum operations increased rapidly during the last decade and an even 

 more rapid increase is anticipated for the next two decades. Noise generated during offshore 

 drilling operations may become noise pollution for some acoustic sensors (ref 1 ). Early off- 

 shore drilling activities were concentrated in shallow water regions (eg, the Gulf of Mexico), 

 but future exploration and production facilities will extend to water several thousand feet 

 deep. These deep water noise sources will have better acoustic coupUng to deep oceanic 

 waters, and thus the noise may impact larger areas. 



The Environmental Protection Agency (EPA) has identified the need for information 

 on the effects of noise on wildlife (ref 2). The EPA recommended studies to determine (1) 

 the effects of low-level chronic noise on animals, and (2) the effects of noise on animals in 

 their natural habitat (ref 3, 4). 



The Bureau of Land Management has identified two aspects of outer continental 

 shelf gas and oil activities that may impact marine mammals: ( 1 ) the effects of underwater 

 sounds emitted from oil and gas operations on cetacean behavior, and (2) the impact of off- 

 shore structures and associated human activities on cetacean populations. 



The effects of noise on man and animals has been documented (see ref 5, 6 for 

 review). The effects of noise are classified as ( I) effects on the auditory system resulting in 

 loss of hearing or damage to the auditory mechanism, or (2) nonauditory effects of noise. 



In the first case, loss of hearing or damage to auditory structures can be produced by 

 brief exposures to very intense sounds or prolonged exposures to moderate levels of sound. 

 Noise with different frequency spectra have different effects on auditory structures. High 

 frequency pure tones or narrow bands of noise tend to produce changes in localized regions 

 of the inner ear. Low frequency or random and broadband noise tend to produce changes 

 throughout the cochlea. The extent of noise-induced damage to the auditory system de- 

 pends on the intensity, spectrum, duration and the exposure pattern of the noise source. 

 Rest intervals between periods of exposure significantly reduce the extent of permanent 

 damage. 



Underwater Systems, Inc. Note 312-5, Noise measurements from Offshore Oil Rigs, p 17, Silver Springs, 

 MD, 1973. 



" Information on Levels of Environmental Noise Requisite to Protect Public Health and Welfare with an 

 Adequate Margin of Safety, Environmental Protection Agency, Superintendent of Documents, U.S. 

 Government Printing Office, Washington, D.C., 1974. 



The White House, Executive Order No. 1 1644, as amended May 24, 1977. 



Janssen, R, Noise and Animals: Perspectives of Goverrunent and Public Policy, In: Effects of Noise on 



WildUfe, JL Fletcher and RG Busnel, ed, p 287-301 , Academic Press, New York, NY, 1978. 

 Kiyter, KD, The Effects of Noise on Man, p 633, Academic Press, New York. NY, 1970 

 Welch, BL and AS Welch, ed. Physiological Effects of Noise, p 365, Plenum, 1970. 



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