Factors Associated With Health Complaints Among Leather Tannery Workers in Bangladesh

The Tanning Process

The tanning process mainly consists of four steps including beamhouse operation, wet finishing, dry finishing, and packing as recommended by the European Commission (Black et al., 2013; Buljan & Kral, 2019; Sathiyamoorthy et al., 2013). There is a considerable variation in steps between tanneries, depending on the type of leather being produced. There is also significant variation in the scale and types of tanning facilities between developed and developing countries (Stellman, 1998). Tanneries in developed countries like the United States, Australia, and Europe are highly mechanized and use closed automatic systems and many chemicals (Black et al., 2013; Buljan & Kral, 2019), whereas in developing countries like Bangladesh, Pakistan, Afghanistan even India still uses mostly manual work and natural tanning substances with techniques remaining unchanged over a long period (Hashmi et al., 2017; Kesarwani et al., 2015; Öry et al., 1997a).

In the beamhouse, the raw hides are stretched on bamboo frames, by pegs or by spreading on the ground in the mild sun. Beamhouse operation workers are exposed to various dusts and chemical agents during preparatory operations such as soaking, liming, fleshing, deliming, bating, and pickling (Black et al., 2013; Buljan & Kral, 2019). Tanning involves the application of chrome (III) compounds or various barks in the case of vegetable tanning (Sathiyamoorthy et al., 2013). Wet finishing includes splitting, shaving, waxing, and oiling (Black et al., 2013; Buljan & Kral, 2019). Workers do not have direct contact with water or chemicals in this stage; however, they may experience exposure to oil products and chemicals while processing wet hides as well as in the dry finishing stage as drying, shaving, buffing, pressing, padding, and spraying (Black et al., 2013; Buljan & Kral, 2019). Exposure to dust particles generated from leather and paint during operating machinery and spraying are the specific hazards in this stage (Öry et al., 1997a). Finally, several workers perform duties as packers, sweepers, carriers, and mixers of chemicals which are considered “miscellaneous.” The workers in this group have the chance for multiple co-exposures as they move from one section to other during their daily work, and their duties may change from time to time. They carry raw hides and skins and mix chemicals with bare hands.

Occupational Health Concerns

Chemical waste from tanneries’ effluents contain chromate and bichromate salts, aniline, butyl acetate, ethanol, benzene, toluene, calcium salts, chlorine, surfactants salts, sodium sulfide, sulphuric acid, organic matters, toxic or poisonous substance, and dyes (Azom et al., 2012; Rastogi et al., 2008). Approximately 40 different types of chemicals are used in the tanning process, while only 20% of the chemicals are absorbed by the leather, and the remaining 80% is released as waste (Azom et al., 2012; Islam et al., 2014). Tannery workers are exposed to many hazardous materials and processes during the tanning of hides and skins. Chemicals used in the tanning process have been reported as potential irritants and sensitizers to the workers (Febriana et al., 2012a; Hedberg et al., 2018; Kolomaznik et al., 2008; Syed et al., 2010). In addition, infection is a constant hazard to the workers because of exposure to a high concentration of pathogens in the raw materials (Işsever et al., 2007; Skóra et al., 2014). A case-control study from Kenya reported a higher prevalence of dermatological symptoms (20%) compared with a control group due to higher level of chromium exposure among tannery workers (Were et al., 2014). A cross-sectional study in India reported that leather tannery workers frequently complained of low-back pain (61%), asthma (38%), dermatitis (31%), and chronic bronchitis (14%) in the 12 months prior of the survey (Skóra et al., 2014). The prevalence of asthma among tannery workers was estimated at 5.3% in Pakistan (Shahzad et al., 2006), 3% in Istanbul (Işsever et al., 2007), and 20% in Sudan (Mohamed & Musa, 2017), whereas it varied from 2.2% to 38% among the leather tannery workers in India in older studies (Chandrasekaran et al., 2014; Öry et al., 1997b; Shukla et al., 1991). Most of the studies to date reported that occupational exposure to chromium (organic form or protein bound-form) of the tannery workers increases the risk of dermatitis, ulcers, and respiratory illness (Azom et al., 2012; Febriana et al., 2012a; Hedberg et al., 2018; Islam et al., 2014; Işsever et al., 2007; Rastogi et al., 2008; Skóra et al., 2014; Syed et al., 2010; Yoshinaga et al., 2018).

Tanneries in the Hazaribagh area of Dhaka district have been identified as one of the leading causes of environmental pollution in Dhaka city (Muralidhar et al., 2017; Yoshinaga et al., 2018). A cross-sectional study on the health of 276 tannery workers reported the prevalence of diarrhea (71.7%), blood pressure (52.2%), asthma (49.9%), and skin disease (73.9%) among the tannery workers (Mahamudul Hasan et al., 2016). The Society for Environment and Human Development (SEHD) of Bangladesh conducted a survey on the health of 179 tannery workers from six tanneries and reported that 58% of tannery workers suffered from gastrointestinal problems, 31% from dermatological diseases, 12% from hypertension, and 19% from jaundice (Akhtar & Shimul, 2015). Despite the results from multiple surveys, very few studies have reported the association between specific occupational exposure and health complaints in leather tannery workers. No comprehensive occupational disease registry, ongoing health monitoring, health surveillance, and risk assessment activities have been implemented for the tannery industries in Bangladesh where the sociodemographic and housing conditions in tannery workers are different from other countries. In Bangladesh, the tannery workers mostly inhabit the slum area where poor living conditions further influences their health status, whereas the studies from other developing countries did not mention housing and living conditions (Febriana et al., 2012a; Shahzad et al., 2006). In addition, no study has been conducted in Bangladesh to investigate the association between occupational exposures and health complaints among tannery workers. Therefore, we aimed to investigate the association between length of employment and types of work and health complaints among the tannery workers in Dhaka, Bangladesh. This study will provide new information for occupational health practitioners and policymakers in settings where regulations are less strict, and the economy and health care are very different from the developed world.

Study Area, Population, and Data Collection

This cross-sectional study was conducted in a cluster of leather tanneries in Hazaribagh of the south-western region of Dhaka, the capital city of Bangladesh (Figure 1). This study was conducted in 10 large tanneries in the Hazaribagh area of Dhaka between May to August 2017. These tanneries were randomly selected through a lottery as representative of the study area. We collected a list of workers from the administrative departments of the 10 selected tanneries, including the number of workers and their work sections (i.e., handling from rawhide to finished leather). From this list, we randomly selected 231 full-time workers at least 16 years of age. All workers were involved in the manufacturing or processing tasks within the tannery. Workers from administrative and other departments, who were not directly involved in the manufacturing or processing tasks, were excluded. All workers were involved in leather tanning processes and had a minimum of 2 years of working experience in tannery work. The respondents were classified into ever smoker and never smoker according to their smoking status. Smoking daily or occasionally or former smokers were classified as ever smoker. Education level was grouped into illiterate (no education), primary education (up to 5 years), secondary education (6–12 years), and graduate (>12 years) education. The housing condition of the participants was classified into kacha house (traditional village house which is made of mud, wood or bamboo, straw, and dry leaves and the floor is made by soil), tin shade house (wall of this house is made by soil or brick, the floor could be soil or brick but the roof is tin), slum house (this house is typically made by various waste materials such as cardboard, tin or plastic; the wall is sometime made of tin or is just a fence where the roof is covered by tin or polythene), or a building. Monthly income was defined as respondent’s personal income from wages and overtime. The study participants were de-identified, and written consent was obtained from all the participants prior to the interview. Ethical approval was obtained from the Northern University Bangladesh human research ethics committee.

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Figure 1.

Study area in Hazaribagh Thana, Dhaka Metropolitan City, Bangladesh.

Occupational Exposure and Health-Related Questionnaires

Self-reported information was obtained from participants through face-to-face interviews. A standardized semi-structured questionnaire was used for data collection. The questions on breathing difficulty and the occupational history questions were adapted from the European Community Respiratory Health Survey (ECRHS) (Le Moual et al., 2014) and Tasmanian Longitudinal Health Study (TAHS) (Matheson et al., 2016). The information was collected on demographic characteristics, previous and current job responsibilities, history of injuries at the workplace, knowledge, and use of personal protective equipment (PPE) (including face mask, cap, apron, goggles and shields, gloves, ear plugs, respirators, and safety shoes/boots) and length of employment. The health-related questions asked the participants whether they had any known lung disease or airway disease, history of chest tightness or shortness of breath with wheezing or breathing difficulty, history of jaundice, and any kind of skin disease/itching. The questionnaire was initially developed in English and translated into local (Bengali, national language of Bangladesh) language, and the interview was conducted into the local language using a local interpreter.

Exposure Measures

Self-reported exposure variables were the length of employment and types of work in the tannery industry. The length of employment was defined as total years of work in the tannery industry, and it was collected as a continuous measure. Types of work were defined as all the workers were assigned any one of the four exposure groups that best fit their daily activities (beamhouse, wet finishing, dry finishing, and miscellaneous).

Outcome Measures

Any affirmative response to one or more of the four respiratory questions became “yes” for the “breathing difficulty” variable for the last 12 months. The four respiratory questions were (a) “Has your doctor told you that you have asthma or asthmatic conditions?” (b) “Have you ever suffered from any lung disease or airway disease?” (c) “Do you usually suffer from shortness of breath with wheezy breathing?” and (d) “Do you usually suffer from tightness of chest or difficulty of breathing? Skin disease was identified as an affirmative response to the question, “Have you ever suffered from any skin disease or itching after starting the job at tannery?” History of jaundice was defined as an affirmative response to the questions, “Do you have any history of jaundice after starting the job at tannery?” Injuries at the workplace was defined by a combination of (a) any kind of accident due to mechanical process (knife, handling mechanics, etc.) at the workplace and (b) any kind of accident due to chemical process at the workplace after starting the job at tannery. All the questions have two response options (Yes/No). When the participants answered “Yes,” they were considered or combined (breathing difficulty and injuries at the workplace) as a positive response to the respective outcomes variable.

Statistical Analysis

We used Stata statistical software for Windows, Version 14.2 (Stata Corp, College Station, Texas) for data analysis. Univariate and multivariate logistic regression models were used to investigate the association between length (years) of employment, types of work, and health complaints among the tannery workers (binary variables), in which odds ratio (OR) with 95% confidence intervals (CIs) we calculated. A two-sided p value of ≤.05 was considered to be statistically significant. In the multivariate model, we included age (continuous variable), smoking status (ever smoker/never smoker), education (illiterate, primary, secondary, and graduate), and personal income (converted into USD) as potential confounders. Confounders were selected based on prior literature review and retained in the model if inclusion changed the point estimate by ≥10%. The length (years) of employment was analyzed as a continuous variable. Types of work were classified into four categories: beamhouse, wet finishing, dry finishing, and miscellaneous which was used as a reference group for the analysis.

Implications for Occupational Health Practice

Leather tannery workers in nonmechanized tanneries are exposed to various chemicals at the workplace. Some health effects may be immediate, such as rhinitis, muscle pain, headache, jaundice, an injuries at the workplace, but others take time to develop, for example, skin disease and breathing difficulties. In Bangladesh, the Occupational Health Service is maintained by the Department of Inspection for Factories and Establishment (DIFE) under the Bangladesh Labour Act (2006) along with other existing regulations (details in online supplement). The working conditions in Bangladesh depend on the environment and workplaces where the tannery workers work but are very poor in general. This is partly due to the specific contractual situation of many tanneries. Most of the tanneries hire the workers on a contract basis where the workers are hired by a company but work within the premises of one or more “host companies.” The employer, that is, the tannery, is responsible for the health and safety of their cleaning workers but is not in control of the environment in which they work in the host company. Because tannery work comprises a wide variety of tasks, workers are potentially exposed to a wide variety of chemical, biological, physical, and psychosocial risks.

The tanneries have been relocated to improve environmental conditions; however, it remains controversial to what extent this relocation will contribute to environmental sustainability and improvement in occupational health of the tannery workers (Hoque & Clarke, 2013). There is a widespread assumption in the government circles that constructing a central Effluent Treatment Plant (ETP) in Savar will resolve the environmental and health issues related to the Hazaribagh tanneries (Human Rights Watch, 2012). However, Human Rights Watch recognized that a central ETP would do nothing to resolve most of the problems such as poor occupational health and safety conditions, hazardous child labor, and the existing industrial pollution of Hazaribagh (Human Rights Watch, 2012). They argued that without closely monitoring and regulating the tanneries in addition to rigorous enforcement of the country’s labor, and environmental laws by the government, there is no incentive for the tanneries to reduce their pollution load by adopting such measures (Human Rights Watch, 2012).

Early interventions in the form of education and training of the workers and employers, by involving public and occupational health authorities as well as worker advocates, may reduce the risk of occupational exposure. Even in the absence of adequate occupational health care facilities in the workplace, public health professionals can take steps to improve the health outcomes for the tannery workers. Greater attention should be committed to employer education, workers’ education, and primary health care. Many employers overlook the effect of prolonged chemical exposure on tannery workers in spite of requirements to monitor their health. Health education is another option to advise employers about risk in their tannery as well as the steps required to mitigate the risk. Moreover, a large proportion of workers do not use PPE during handling tannery materials or chemicals because of lack of availability of PPE or lack of awareness about PPE. Workers’ education about smoking cessation and the importance of hygiene prior to eating and leaving work as well as how PPE and work practice can reduce exposure could minimize the risk of injuries or illnesses in the tannery industry. Health monitoring in the tannery industry together with exposure control measures are required to prevent adverse health impacts.