An Integrated Noise-Protection Program in Angola
Authors: Carpenter Chris 
Published: February 2015

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 157292, ’Integrated Noise Protection Program - From Noise Measurements to Epidemiology,’ by Tania Batalha, Nico De Sadeleer, and Stephan Plisson- Saune, Total E&P Angola, prepared for the 2012 SPE/APPEA International Conference on Health, Safety, and Environment in Oil and Gas Exploration and Production, Perth, Australia, 11-13 September. The paper has not been peer reviewed.
An epidemiological study was developed to take into account specific employee habits while measuring the possible prevalence of hearing problems arising from earlier occupational exposure. During 30 years of war, Angolans were exposed to high levels of noise, a factor exacerbated by the offshore environment many workers now share. A population of nonexposed staff, largely administrative, was compared with a population of offshore workers. The results did not show any significant difference in hearing capabilities.
Introduction
Noise-induced hearing loss (NIHL) is the most prevalent irreversible industrial disease, and noise is the most prevalent compensable occupational hazard. In developing countries, occupational noise and urban environmental noise are increasing risk factors for hearing impairment, which may lead to increased incidence of accidents at work.
Unlike most other occupational injuries, NIHL occurs without any visible exterior evidence or trauma and is perceived too late. While irreversible, it is fully preventable with proper job design, training, and protection measures. The estimated cost of noise to developed countries ranges from 0.2 to 2% of gross domestic product. However, there is a lack of accurate epidemiological studies on prevalence, risk factors, and costs of NIHL, particularly in developing countries.
In an audiogram, the decrease in the hearing threshold is detected at an early stage, allowing preventive measures to be taken. Changes in audiometric tracings are common and usually bilateral. Changes in the hearing threshold involve an initial notch at high frequencies of 3,000, 4,000, and 6,000 Hz, which, over 10 to 15 years of exposure, reach a maximum of 75 dB. Thereafter, medium and low frequencies are gradually affected up to a maximum of 40 dB.
Noise-Exposure Risks in Angola
Social and Environmental Exposure. During the civil war that ended in 2002, people were exposed to high noise peaks from gunfire, explosions, and tank battles. Throughout this period, no medical assessments or epidemiological data were available. There is no public law on noise pollution, and, in Luanda, nightclubs play loud music throughout the night from Thursday until Monday. Common transport buses have powerful sound systems, exposing drivers, riders, bystanders, and other commuters in numerous traffic jams to noise peaks. Traffic in Luanda during the week is heavily congested, and there is a constant cacophony of car horns and car alarms. Industry workers are exposed to noise during offshore drilling and production operations, onshore logistics operations, and air travel. Currently, there is no national labor legislation enforcing noise limits.