Exposure to noise in the manufacturing industry in Brazil

Abstracts

A exposição ao ruído no trabalho é o fator de risco modificável mais importante para a perda auditiva em adultos. Na indústria de transformação, a exposição a níveis elevados de pressão sonora afeta um grande número de trabalhadores. As normas brasileiras estabelecem como obrigatório, para todas as empresas, o monitoramento do ruído ocupacional e da condição auditiva dos trabalhadores, assim como garantias para a proteção do trabalhador. No entanto, a aplicação das normas é frágil e pouco se sabe sobre a distribuição de exposição ao ruído no País. Este estudo tem como objetivo investigar e sumarizar a distribuição da exposição ao ruído e do uso do equipamento de proteção auditiva entre trabalhadores da indústria de transformação no Brasil. A menor prevalência de exposição ao ruído dentre os ramos da indústria da transformação é de 45% e poucos são os dados sobre o uso do equipamento de proteção auditiva entre os trabalhadores expostos. Comparando-se os disponíveis para os diferentes ramos de atividade, a exposição ao ruído alcança níveis mais altos no ramo da fabricação de produtos de madeira, onde também se observa a menor proporção de uso do equipamento de proteção auditiva. A escassez de dados sobre as condições de trabalho, exposição ao ruído e proteção auditiva, limita os esforços em fazer com que a saúde auditiva seja incluída entre as prioridades da saúde pública no Brasil.

Ruído; Indústrias; Perda Auditiva Provocada por Ruído; Saúde do Trabalhador

REVISION ARTICLES

^IUndergraduate student from the Speech Language Pathology course at the Federal University of Bahia - UFBA, Salvador, Bahia, Brazil

^IISpeech Language Pathologist; Adjunct Professor of the Department of Speech Language Pathology at the Federal University of Bahia - UFBA, Salvador, Bahia, Brazil; PhD in Public Health at the Public Health Institute of the Federal University of Bahia

^IIIUndergraduate student from the Speech Language Pathology course at the Federal University of Bahia - UFBA, Salvador, Bahia, Brazil

Mailing Address

ABSTRACT

Occupational noise exposure is the most important modifiable risk factor for hearing loss in adults. The manufacturing industry has elevated levels of noise exposure that affect a large number of workers. The Brazilian norms state that noise and hearing function must be monitored, along with safeguards to protect workers, these are compulsory for all companies. However norms enforcement is weak and little is known about noise exposure distribution in the country. The purpose of this study is to investigate and summarize the distribution of noise exposure and use of hearing protection devices among workers in the manufacturing industry in Brazil. Among the manufacturing industry trends the minimum prevalence of noise exposure is 45%, and there are only a few data on the use of hearing protection device against hearing loss. Comparing available data from different industry trades, levels of noise exposure are higher in the logging and wood processing industry, together with a lower proportion of hearing protection device usage. The lack of data on work conditions, noise exposure and hearing protection limits the strength of hearing health among public health priorities in Brazil.

Keywords: Noise; Industry; Noise-Induced Hearing Loss; Occupational Health

INTRODUCTION

Exposure to high levels of environmental sound pressure is associated with negative effects for humans¹. In the production plants of the factories, processes mediated by the functioning of machines produce unwanted noise, usually intense, with the potential to cause damage to the hearing of workers². The loud noise is common in many production processes and hence the exposure to noise at work is considered a most relevant modifiable risk factor to hearing loss in adults³.

The gradual decrease in hearing acuity, usually bilateral and symmetric, due to continuous exposure to high sound pressure levels, featuring noise-induced hearing loss (NIHL) - work related disease, common in industrialized countries and which stands out as one of the main hazards in the health of the worker from the Brazilian industry^4,5. The individual with NIHL may present intolerance to loud sounds, tinnitus, and have compromised speech intelligibility, which impacts negatively on their communication process⁶ and therefore in their quality of life. In addition to the auditory effects, others may arise from exposure to noise, including headache, gastric disturbances, increased blood pressure, insomnia and irritability^7,8.

Brazil, in its legislation, recognizes that activities or operations that expose workers to noise levels above 85 dB (A) for eight hours or more without adequate protection, offer serious and imminent risk to health⁹. Brazilian standards set as mandatory for all companies, the monitoring of occupational noise and hearing status of workers, as well as guarantees for the protection of workers¹⁰. Although collective measures, implemented to reduce the noise level in plants, are the most effective in protecting the hearing health of workers, individual measures are the most commonly used by the employer, usually limited to the provision of hearing protection equipment^11-13. It is known that simply supplying the equipment does not guarantee the adoption of its use by the employee. The security behavior is influenced by several factors such as the security climate in the company, recognizing the benefit to their own health, frailty surveillance, among others^14,15.

In Brazil, there are few data on noise exposure in the economically active population, hindering the projection of estimates of the number of workers exposed and the identification of the industries that offer higher risk; useful information for the surveillance and prevention of NIHL.

The industry focuses work processes most commonly linked to prolonged exposure of workers to noise, but little is known about the distribution of exposure among its various sections and divisions. According to the National Classification of Economic Activities (CNAE - Classificação Nacional de Atividades Econômicas), companies usually noisy, such as lumber and metallurgic, are classified in the section named "Manufacturing Industry". Regulatory norm number 4 (RN-4) assigns to the Manufacturing Industry risk levels 2, 3 and 4, on a scale 1-4, whose values measure the Specialized Services at Safety Engineering and Occupational Medicine (SESMT⁹ - Serviços Especializados em Engenharia de Segurança e em Medicina do Trabalho).

METHOD

Searches were conducted in the LILACS and SciELO electronic databases, covering the period from January 1995 to August 2011, using combinations of the key words, terms and expressions: "noise", "industry", "hearing loss" and "induced hearing loss by noise". The reference lists of identified articles were also used as a data source. As inclusion criteria, studies should have been conducted with data from companies based in the country, with activity classified in the "C" session of the National Classification of Economic Activities (CNAE - Classificação Nacional de Atividades Econômicas), corresponding to the Manufacturing Industry, besides the publications should contain specific information on the intensity of noise in the workplace, and/or allowing the estimation of at least one of the following measures: prevalence of noise-exposed workers in the company, the proportion of hearing protector use among those exposed to noise.

The CNAE is the national instrument of standardization of codes of economic activity and the criteria framework used by the various organs of public administration in the country. This standardization helps to improve the quality of information systems that support the decisions and actions of the state, and also enable greater interaction intersystem. The most current version of this classification is the CNAE 2.0, hierarchically structured in five levels with 21 sections, 87 divisions, 285 groups, 672 classes and 1301 subclasses. The Manufacturing Industry corresponds to the "C" session of the CNAE, including activities that involve significant physical, chemical and biological materials, substances and components in order to obtain new products. This section has 24 divisions, numbered from 10 to 33, which correspond to different types of economic activity, presented in Table 1.

The purpose of this research is to organize and present, in a summarized way, information and/or conducted estimates based on the data identified in the articles selected for the following measures, when available: noise intensity in the workplace, prevalence of workers exposed to noise the company, and the proportion of hearing protector use among workers exposed.

LITERATURE REVIEW

25 studies were identified from which 18^1,2,5,16-30 met the inclusion criteria, i.e., using data from the manufacturing industry in Brazil and reported specific measures for the noise intensity, and/or data that allowed an estimated proportion of exposed workers or the use of hearing protectors in the exposed group. Out of the 24 divisions of the "C" session of the CNAE - Manufacturing Industry - only 13 were represented in the studies (Table 2). The division corresponding to metallurgy stood by the largest number of studies (n = 8), followed by manufacturing wood products (n = 6), food products (n = 4), and the divisions corresponding to the manufacture of non-metal mineral products (n = 3), textiles (n = 2), articles of apparel and accessories (n = 2), pulp, paper and paper products (n = 2), among others that were considered in only one study. Four studies investigated workers in different industries, being classified then in more than one division of the CNAE. Based on the criteria for inclusion, no study included workers from the other 11 from the 24 divisions of the Manufacturing Industry, such as the manufacture of motor vehicles, furniture manufacturing and maintenance and repair of equipment, and involving a potentially noisy substantial number of workers in the country. Thus, there is a shortage of information, with few studies which limit themselves to about half of the manufacturing industries in. This condition can be the result of several factors such as the barriers imposed by certain industries to access to data of the conditions of the work environment and on workers themselves, lack or inaccurate data presented in the publications, and the invisibility of the possible noise problem in some industries.

The noise intensity in plants was recorded in 17 (94%) of these studies, establishing itself as the most common of the information of interest in this research (Table 2). The values included consistently higher levels of 85 dB (A). However, specific data for the minimum and maximum sound pressure were identified in only 13 studies (72%). The maximum recorded among the companies reached 126 dB (A) - corresponding to the division of the lumber industry - although most have registered maximum sound pressure level between 102-115 dB (A). These results demonstrate that the sound pressure levels observed in this sub-sector of the industry outweigh significantly the tolerance limit of 85 dB (A), reaching 126 dB (A) at its plants. Companies with the highest levels of noise were lumber and metallurgical. Accordingly, they are classified into branches of economic activities that pose the greatest risk levels 3 and 4, respectively, according to the Labor Department⁹.

Information or data that allowed an estimated prevalence of noise exposure in the companies were registered in only four studies (22%) (Table 2). Specifically, the share of workers exposed to noise reached 92.0% in lumber industries¹⁶ and 82.1% in the pulp and paper industry¹⁷, 51.6% in four industries (three sugarcane and one metallurgical)¹⁸, and 45.2 % in a group of companies representing various branches of the industry, but that included different activities, such as service¹⁹. The estimated prevalence of noise exposure to some of the other branches of the CNAE would be feasible if it were available the total number of employees of the respective companies, however, this was rarely presented in a given studies. The results presented here suggest that, in general, more than half of the individuals employed in manufacturing work exposed to loud noise.

Data recorded in seven studies (39%) allowed identifying and/or estimating the proportion of the use of hearing protection equipment among workers exposed to noise (Table 2). This measure showed significant variation among workers exposed to different branches from the Manufacturing Industry. However, there were 19 branches with no information available. A smaller proportion of the hearing protector use was observed in the manufacturing industry and wood products (29.6% and 50.0%). Consistently, the study by Pignati and Machado (2005) shows a serious situation after analyzing 1,381 loggers in the state of Mato Grosso: 73% of jobs in sawmills did not provide any type of personal protective equipment to workers.

It should be emphasized that the lumber industry had the highest measure of sound pressure of noise in the workplace, 126 dB (A), the highest proportion of exposed workers, and poorest use of hearing protection equipment often unavailable for worker. Thus, the results reveal, in a special way, the situation of vulnerability in which workers are manufacturing wood products (D.16), suggesting them as a priority group for intervention.

The lack of basic data on noise exposure in publications restricted the number of articles included in the analysis, and hence the representation of the divisions of this branch of industry. Thus, the results should be interpreted appropriately, considering the limitations of the study's findings, especially in the comparison between these divisions. Despite the limitations, the lack of information was one of the reasons for its development, with the intention of revealing the accumulated knowledge, and the weaknesses and omissions in the data area publications, and thus encouraging the inclusion of data from epidemiological interest in the production knowledge about exposure to noise.

The potential harmful effects of noise on health, especially hearing health, reinforce the need for investment in management actions and continuous evaluation of the Hearing Loss Prevention Programs in the manufacturing industries in the country.

The presentation of epidemiological data in the scientific literature on noise exposure among workers in Brazil is still insufficient, restricting knowledge about the working conditions and hearing health of the population. Consequently, there are difficulties in identifying priority areas for intervention, and important limitations to the efforts that could be undertaken to include hearing health among public health priorities in the country. This type of information is essential to generate estimates and support decisions and actions in favor of the health of individuals exposed to risks in their work routine.

CONCLUSION

The results of this review reveal a gap in information about noise exposure on almost half of the industries in the manufacturing industry in Brazil. Among the industries with information, noise exposure reaches at least 45% of the workforce. The sound pressure level exceeds 85dB in all branches, and achieves 126dB (A) in the lumber industry. There is little information on the proportion of workers using hearing protection equipment, with wide variation between branches. Noteworthy is the branch of manufacture of wood products, with evidence of non-availability of equipment to workers, a situation aggravated by presenting the highest level of noise intensity, and also the higher prevalence of exposed workers. The absence of the total number of employees by industry in scientific production was a common problem, and therefore it should be reinforced the importance of this practice, which contributes to an estimated prevalence of noise exposure in different industries. New research on the topic is needed, in particular, focusing on working conditions and hearing protection for workers in fields of activity for which there is no information.

REFERENCES

• 1. Araújo SA. Perda auditiva induzida pelo ruído em trabalhadores de metalúrgica. Rev Bras Otorrinolaringol. 2002;68(1):47-52.
• 2. Caldart AU, Adriano CF, Terruel I, Martins RF, Caldart AU, Mocellin M. Prevalência de perda auditiva induzida pelo ruído em trabalhadores da indústria têxtil. Arq Int Otorrinolaringol. 2006;10(3):192-6.
• 3. Dobie RA. The burdens of age-related and occupational noise-induced hearing loss in the United States. Ear Hear. 2008;29(4):565-77.
• 4. Almeida SIC, Albernaz PLM, Zaia PA, Xavier OG, Karazawa EHI. História natural da perda auditiva ocupacional provocada por ruído. Rev Assoc Med Bras. 2000;46(2):143-58.
• 5. Guerra MR, Lourenço PMC, Bustamante-Teixeira MT, Alves MJM. Prevalência de perda auditiva induzida por ruído em empresa metalúrgica. Rev Saúde Pública. 2005;39(2):238-44.
• 6. Comitê Nacional de Ruído e Conservação Auditiva. Boletim nş 6: Perda auditiva induzida por ruído relacionada ao trabalho. Arq Int Otorrinolaringol. 2000;4(2):125.
• 7. Fernandes M, Morata TC. Estudo dos efeitos auditivos e extra-auditivos da exposição ocupacional a ruído e vibração. Rev Bras Otorrinolaringol. 2002;68(5):705-13.
• 8. Lusk SL, Hagerty BM, Gillespie B, Caruso CC. Chronic effects of workplace noise on blood pressure and heart rate. Arch Environ Health. 2002;57(4):273-81.
• 9. Ministério do Trabalho e Emprego. Portaria 3.214 de 8 de junho de 1978. Aprova as Normas Regulamentadoras do Capítulo V do título II da Consolidação das Leis do Trabalho, relativas à Segurança e medicina do trabalho. Diário Oficial da União 1978; 9 jun.
• 10. Ministério da Saúde, Secretaria de Atenção à Saúde, Departamento de Ações Programáticas Estratégicas. Perda auditiva induzida por ruído (PAIR)-(Série A. Normas e Manuais Técnicos) (Saúde do Trabalhador; 5. Protocolos de Complexidade Diferenciada) - Brasília: Editora do Ministério da Saúde, 2006. Disponível em: <http://bvsms.saude.gov.br/bvs/publicacoes/protocolo_perda_auditiva.pdf>
• 11. El Dib RP, Atallah AN, Andriolo RB, Soares BGO, Verbeek J. A systematic review of the interventions to promote the wearing of hearing protection. São Paulo Med J. 2007;125(6):362-9.
• 12. Nelson DI, Nelson RI, Concha-Barrientos M, Fingerhut M. The global burden of occupational noise-induced hearing loss. Am J Ind Med. 2005;48(6):446-58.
• 13. Concha-Barrientos M, Nelson DI, Driscoll T, Steenland NK, Punnett L, Fingerhut, MA et al. Selected occupational risk factors. IN: Ezzati M, Lopez AD, Rodgers A, Murray CJL, editores. Comparative Quantification of Health Risks: Global and Regional Burden of Disease Attributable to Selected Major Risk Factors. Geneva: World health Organization; 2004. p. 1651-801.
• 14. Garcia AM, Canosca PB. Why do workers behave unsafely at work? Determinants of safe work practices in industrial workers. Occup Environ Med. 2004;61(3):239-46.
• 15. Neal A, Griffin MA, Hart PM. The impact of organizational climate on safety climate and individual behavior. Saf Sci. 2000;34:99-109.
• 16. Pignati WA, Machado JMH. Riscos e agravos à saúde e à vida de trabalhadores das indústrias madeireiras de Mato Grosso. Ciênc Saúde Coletiva. 2005;10(4):961-73.
• 17. Fassa AG, Facchini LA, Dall'Agnol MM. Trabalho e morbidade comum em indústria de celulose e papel: um perfil segundo setor. Cad Saúde Pública. 1996;12(3):297-307.
• 18. Gonçalves CGO, Iguti AM. Análise de programas de preservação da audição em quatro indústrias metalúrgicas de Piracicaba, São Paulo, Brasil Cad Saúde Pública. 2006;22(3):609-18.
• 19. Teles RM, Medeiros MPH. Perfil audiométrico de trabalhadores do distrito industrial de Maracanaú - CE. Rev Soc Bras Fonoaudiol. 2007;12(3):233-9.
• 20. Vivan AG, Morata TC, Marques JM. Conhecimento de trabalhadores sobre ruído e seus efeitos em indústria alimentícia. Arq Int Otorrinolaringol. 2008;12(1):38-48.
• 21. Oliva FC, Morata TC, Lacerda ABM, Steinmetz L, Bramatti L, Vivan AG, et al. Mudança significativa do limiar auditivo em trabalhadores expostos a diferentes níveis de ruído. Rev Soc Bras Fonoaudiol. 2011;16(3):260-5.
• 22. Zocoli R, Silva AMP. Perfil audiológico em indústrias madeireiras. Rev Bras Otorrinolaringol. 1995;61(3):188-92.
• 23. Rocha R, Porto M, Morelli MYG, Maestá M, Waib PH, Burini RC. Efeito de estresse ambiental sobre a pressão arterial de trabalhadores. Rev Saúde Pública. 2002;36(5):568-75.
• 24. Boger ME, Barbosa-Branco A, Ottoni AC. A influência do espectro de ruído na prevalência de Perda Auditiva Induzida por Ruído em trabalhadores. Rev Bras Otorrinolaringol. 2009;75(3):328-34.
• 25. Lopes AC, Santos CC, Alvarenga KF, Feniman MR, Caldana ML, Oliveira AN, et al. Alterações auditivas em trabalhadores de indústrias madeireiras do interior de Rondônia. Rev Bras Saúde Ocup. 2009;34(119):88-92.
• 26. Queiróz MFF, Maciel RH. Condições de trabalho e automação: o caso do soprador da indústria vidreira. Rev Saúde Pública. 2001;35(1):1-9.
• 27. Ribeiro FSN, Oliveira S, Reis MM, Silva CRS, Menezes MAC, Dias AEXO, et al. Processo de trabalho e riscos para a saúde dos trabalhadores em uma indústria de cimento. Cad Saúde Pública. 2002;18(5):1243-50.
• 28. Abreu MT, Suzuki FA. Avaliação audiométrica de trabalhadores ocupacionalmente expostos a ruído e cádmio. Rev Bras Otorrinolaringol. 2005;68(3):488-94.
• 29. Gonçalves CGO. Implantação de um programa de preservação auditiva em metalúrgica: descrição de uma estratégia. Disturb Comum. 2004;16(1):43-51.
• 30. Botelho CT, Paz APML, Gonçalves AM, Frota S. Estudo comparativo de exames audiométricos em metalúrgicos expostos a ruído e ruído associado a produtos químicos. Rev Bras Otorrinolaringol. 2009;75(1):51-7.

Exposure to noise in the manufacturing industry in Brazil

Franciana Cavalcante^I; Silvia Ferrite^II; Tatiane Costa Meira^III

Publication Dates

• Publication in this collection
  10 May 2013
• Date of issue
  Oct 2013

History

• Received
  18 Jan 2012
• Accepted
  27 Apr 2012