Occupational hazard exposure and general health profile of welders in rural Delhi

Abstract

Background:

Welding is a common industrial process associated with various health hazards. The aspect of duration of hazard exposure among welders at their workplace has been studied to limited extent in India.

Objective:

To assess the duration of occupational hazard exposure and its association with symptoms among the welders.

Materials and Methods:

A cross-sectional study was conducted amongst 106 welders in North Delhi. Data was collected using a questionnaire containing items to assess the socio-demographic profile, their medical history and individual hazard exposure.

Results:

Majority of them were involved in skilled/semi-skilled job (n = 99; 93%). The predominant nature of work for majority was manual. More than half reported their work to be physically hard (n = 56; 53%), involves much lifting of weight (n = 61; 57%), and is dangerous (n = 59; 56%). Dust/smoke followed by noise was reported to be most common hazards at the workplace by them. Most of them were suffering from eye related symptoms (n = 63; 59%) followed by skin conditions (n = 28; 26%). Skin diseases were reported to be significantly common among group of welders who were exposed to dust and radiation for ≥4 hours in a day (P < 0.05).

Conclusions:

Nearly half of the welders found their job to be dangerous and were being exposed to at least one hazardous substance at their workplace. Majority of them complained of eye symptoms. There is a need for health and safety training of this economically productive group.

INTRODUCTION

Workplace is an important part of human environment. The health and efficiency of workers in any organization get influenced in large extent by conditions in their work environment.[1] It is an established fact that no occupation is without risk of hazard. There are varieties of hazards in the occupational environment to which workers may be exposed and which may cause various diseases. These are related to physical condition such as temperature, humidity, noise, light, chemical agents in the form of vapors, fumes, droplets, gases; and unsafe and unprotected machines and technical equipments responsible for causing accidents.[2]

According to World Health Organization (WHO), there are about 250 million cases of work-related injuries per year worldwide.[3] One of the jobs that contribute to these occupational injuries is the welding process, especially in developing countries.[4] Welding is common indispensable procedure in engineering works and is associated with varied health hazards apart from injuries. Some of the hazards of this occupation include ultraviolet (UV) and infrared (IR) radiation exposure, fumes and particulate generation, thermal burns, occupational heat stress, exposure to electromagnetic fields, and electrocution.[5] Similarly, the excessive lighting (glare) and exposure to UV radiation may lead to ‘arc eye’ or ‘flash burn’ injuries to the cornea, photo-keratosis and double vision and consequent retinal damage.[5,6] Welders are also exposed to noxious metal fumes, depending upon process and material containing a concoction of metals like zinc, copper, cobalt, nickel, chromium, platinum, and their oxides leading to various respiratory dysfunctions and influenza-like condition called metal fume fever.[4,7,8] Metal fume fever is characterized by chills, thirst, fever, muscle ache, chest soreness, coughing, wheezing, fatigue, nausea and a metallic taste in the mouth. Other short term effects include irritation to eyes, nose, throat, chest and respiratory tract; gastrointestinal symptoms nausea, vomiting and cramps. Studies of welders, flame cutters, and burners have shown that welders have an increased risk of lung cancer, and, possibly cancer of the larynx and urinary tract on chronic exposure to the fumes.[9]

The health risks associated with welding gases and fumes are also determined by the length of time one is exposed to them, type of welding engaged in, the work environment and the protection employed.[10] Hence, it is pertinent to keep exposure to harmful gases and fumes below recommended Occupational Exposure Limits (OELs) and for limited duration to curb ill effects on health. However, the aspect of duration of hazard exposure among welders at their workplace has been studied to limited extent in India.

Welders are part of informal occupational sector in India. Hence, they do not have any organized occupational health services. Further, very limited attempts have been made to study occupational exposure and health profile of this population in India. Therefore, the present study was undertaken to assess the duration of occupational related exposure to various hazards and health of the workers.

MATERIALS AND METHODS

Study settings and participants

It was a community based cross-sectional study conducted among welders working in Pooth Khurd village near Bawana Industrial Area of North-west district of Delhi. It is a village located near Delhi-Haryana border and consequently has lot of migrant population from the neighbouring states. According to census 2001, the population of the village was 8,167.[11] More than 75% of the males in the village are employed outside the agriculture. Being located near an industrial area, there are numerous mechanic workshops, motor spare parts market and small-scale industries. Welders are located around these workshops. Taking prevalence of morbidities among welders to be 50% (as there are no available studies in the Indian setting) with 95% confidence interval and precision of 10%, sample size was estimated to be 96. However, 106 welders working in the area consented to participate.

Inclusion criteria

All workers above 15 years of age, involved in Manual Metal Arc Welding for at least 1 year were included in the study.

Study tool

A pre-tested, semi-structured interviewer based questionnaire was used for data collection. The questionnaire was prepared after a rigorous literature review.[7,10] The questions were then assessed for suitability, relevance and accuracy in the Indian context by a professional occupational health specialist. The interview schedule was pretested on 35 welders from Gokulpuri in East District of Delhi. The alpha Cronbach coefficient of the questionnaire was calculated to assess internal consistencies of items and was found to be 0.67.

The schedule included questions pertaining to age, gender, state of origin, marital status, education, job status, income and type of housing of the study participants. The schedule also included seven items for assessment of nature of work and exposure to chemicals, heat, dust/smoke, noise, radiation, cold, vibration and fumes on daily basis. Exposure was calculated in hours per day. Past history of diseases such as jaundice, skin diseases, burns, allergy, low back pain (LBP), tuberculosis, joint problems, hypertension, respiratory symptoms such as breathlessness, cough etc., and eye related symptoms in last one month and last one year were elicited from the participants.

Definition of variables

• Housing variables: A slum is a compact settlement of at least 20 households with collection of poorly built tenements, mostly of temporary nature, crowded together usually with inadequate sanitary and drinking water facilities in unhygienic conditions.[12] Resettlement colony is Jhuggi Jhopri households that have been resettled from their original settlement.[13]

• Type of work: An unskilled employee is one who does operations that involve the performance of simple duties, which require the experience of little or no independent judgment or previous experience although familiarity with the occupational environment is necessary. His work may thus require in addition to physical exertion familiarity with variety of articles or goods.[14] A semi-skilled worker works generally in a defined routine nature, wherein the major requirement is not so much of the judgement and skill but for proper discharge of duties assigned to him or relatively narrow job and where important decisions are made by others. His work is thus limited to the performance of routine operations of limited scope.[14] A skilled employee is one who is capable of working efficiently of exercising considerable independent judgement and of discharging his duties with responsibility. He must possess a thorough and comprehensive knowledge of the trade, craft or industry in which he is employed.[14]

• Technical qualifications: Person has received specialized training at a high school, vocational school or community college in welding.[15]

• Case definitions: Hypertension was defined as blood pressure more than or equal to 140 mm of Hg systolic and/or 90 mm of Hg diastolic according to the seventh report of the joint national committee.[16] Low back pain is defined as pain in lumbar region.[17]

• Symptom classification: Watering of eyes, photophobia and redness of eyes were referred to as eye symptoms, LBP and joint problems were classified as musculoskeletal complaints/diseases and breathlessness and cough was defined as respiratory symptoms.

Study methodology

Before the commencement of the study, a thorough search of welding small-scale industries and mechanic work shop was undertaken. After mapping these places, welders were located and contacted. A three-member team led by the investigator interviewed the welders present on the day of survey and involved in Manual Metal Arc Welding at their workplace. The objective of the study was explained to them and informed consent was obtained before the collection of data. The option to opt out of the study was kept open without any clause. Confidentiality of data was ensured. The ethical committee of the institution approved the protocol of the study.

Statistical analysis

The data collected were coded, entered into Microsoft Excel 2007, and analyzed using Statistical Package for the Social Sciences software (SPSS 16.0, SPSS Inc., 233 South Wacker Drive, 11^th Floor, Chicago, IL 60606-6412). Descriptive statistics, including mean, standard deviation, and range, for quantitative data and proportions for qualitative data were used to characterize the study population. For qualitative data, χ2 or Fischer's exact test was used to observe differences between proportions for independent groups. The difference between the 2 groups was considered significant at 5%.

To study the association of different morbidities with duration of exposure, the groups were divided into two groups, based on the exposure to hazards for duration less than 4 hours and more than equal to 4 hours. The cut-off of 4 hours was taken since the evidence suggests that some of the short term health effects of welding processes develop within 4 hours.[9]

RESULTS

Socio-demographic profile of welders

Overall 106 male welders consented to participate. The mean age of study group was 30.96 ± 11.33 years with 79.2% (n = 84) belonging to 15-39 years age group. Majority of the respondents were married (n = 68; 64%). Nearly one-third of the participants (n = 33; 31%) were educated up to primary level, whereas 27% (n = 29) were illiterate. Out of all, 75% (n = 80) of the participants were residing in resettlement colonies. More than half of the respondents (n = 63; 59%) were from Uttar Pradesh (UP) and only 22% (n = 23) from Delhi. The mean time in years for which the study group has been Delhi was 18.09 ± 13.23 [Table 1].

Table 1.

Socio-demographic profile of study participants (n=106)

Work profile of the welders

There were only seven welders (7%) who were doing unskilled work while rest of them were either involved in semi-skilled (n = 51; 48%) or skilled job (n = 48; 45%). A large proportion of welders (n = 75; 71%) did not possess necessary technical qualifications related to welding. The usual hours of work was reported to be 8.55 ± 1.80 (range = 1-12 hours/day). More than half of the respondents reported that their work to be physically hard (n = 56; 53%); involves much lifting of weight (n = 61; 57%), is dangerous (n = 59; 56%) and nature of work is manual (n = 68; 64%). While 46% (n = 49) said that their work involves to be sitting most of the time and 40% (n = 42) reported to be moving most of the time [Table 2].

Table 2.

Work profile of study participants (n=106)

Exposure to occupational hazards

Dust/smoke (n = 73; 69%) followed by noise (n = 54; 51%) were reported to be most common hazards at the workplace by the welders. Chemical exposure was reported the least (n = 5; 5%) [Figure 1]. The study participants reported that they were being exposed to dust/smoke for 4.41 ± 2.76 hours (Median = 4; interquartile range (IQR) = 2-6 hours), radiation for 2.01 ± 3.35 hours (Median = 0; IQR = 0-3 hours), noise for 2.67 ± 2.71 hours (Median = 2; IQR = 0-5 hours) and heat for 1.92 ± 2.85 hours (Median = 0; IQR = 0-3 hours). The mean duration of exposure to chemicals was negligible (<1 hour) [Figure 2].

Figure 1.

Self-reported exposure to various hazards at workplace

Figure 2.

Duration of Individual Hazard Exposure at workplace

Self-reported health problems among welders

Eye symptoms were the most commonly reported symptoms such as watering of eyes (n = 63; 60%) followed by skin diseases (n = 24; 24%) and LBP (n = 23; 23%) in last month amongst the welders [Table 3]. Skin diseases were reported to be significantly common among group of welders who were exposed to dust and radiation for ≥4 hours in a day (P < 0.05). No significant association was found between eye, respiratory and musculoskeletal symptoms with the duration of exposure of different hazards. Though association with age and morbidities was found to be not significant, eye symptoms were found to be more common among younger age group [Table 4].

Table 3.

Self reported health problems amongst welders (n=106) in last one month and last one year

Table 4.

Association of exposure to hazards and age to presence of various morbidities among welders (n=106)

DISCUSSION

Welding is an important occupational activity in India, and as with other occupations, it is not without health risks. However, this population has been studied in limited extent in Indian settings. Therefore, the present study attempted to assess the duration of exposure to various hazards at workplace and presence of various morbidities among welders at the time of survey and a year prior to it.

Although there are a vast number of processes, it has been estimated that shielded metal arc welding (SMAW, also known as manual metal arc welding, MMAW or stick welding) and gas metal arc welding (GMAW or metal inert gas welding) account for combinations practised by 70% of welders.[7] Hence, study population chosen was primarily those involved with MMAW. The welders in this study were all males pointing towards the gender predisposition towards this occupation, especially in a developing country like India. Also, males tend to select themselves into more hazardous jobs and females are assigned less physically demanding jobs. The finding that majority were in age bracket of 15-39 years (79%) was probably due to apprenticeship setting where there are younger apprentices working under their masters as found in another study done in Nigeria among 758 welders in 2006.[18] Another notable characteristic of our study population was that the large chunk was migrant. Evidently, Delhi is first among Union Territories in term of migrant population according to Census 2001 with largest inflow of workers from state of UP.[19,20]

Even though nearly 60% of the welders in current study had received education less than primary school and did not possess necessary technical qualifications, a large proportion of them were involved in skilled/semi-skilled job. This could point towards the finding of rampant child labor in India.[21] Further, they are referred to casual laborers who have been characterized by chronic poverty.[21] Thus, if they have joined job at earlier age it is better off in the long run as they could learn a vocational skill through apprenticeship and earn a livelihood. In this situation, person would be younger, skilled or semi-skilled without technical qualification. Also, school education is usually academic and theoretical. Similar findings have been reported elsewhere also.[18]

Notably more than half of the respondents found their occupation to be physically hard and dangerous. This proportion is much lower than observed among welders in Benin City (91.6%)[18] and Kaduna Metropolis of Nigeria (77.9%).[4] Lack of awareness about severity of risks associated with one's occupation aggravates the worker's health hazards in the work environment.[22] Thus, this finding point towards the need for education of this group of workers about the workplace hazards.

On an average, welders were spending eight hours daily in this work. Further, nearly half (46%) of the study participants were spending most of the time sitting. This finding has an important implication. Prolonged sitting (usually in squatting position) or standing have been found to be related to high incidence of LBP, particularly more among those involved in sedentary occupation for years.[23] In the current study, nearly one-fifth (23%) of them were suffering from LBP in month prior to survey. This is consistent with study done 330 welders in Nigeria in 2009 where 19% of them were reported to be suffering from LBP. Prolonged sedentary behavior at work place also predisposes them various lifestyle diseases such as diabetes, coronary artery disease and cancers.[24]

Welding operations led to production of gases and small solid particles, together known as welding smoke. Most of this is produced during arc welding.[25] Evidently, in our study, welding smoke was reported to be the most common exposure at the work place followed by noise. The individual components of welding smoke can affect any part of the body.[25] Skin diseases including burns were found to be significantly associated with increasing duration of exposure to dust/smoke. However, no association of duration of exposure was seen with respiratory and eye symptoms. This could probably be due to the fact that smoke causes both short and long-term effects pertaining to these body systems thereby negating the effect of duration of exposure.[9] Also, there is a possibility where welders with severe respiratory diseases were not able to continue in the profession and have stopped working in the welding processes. Similar findings were obtained with radiation exposure.

The most common self-reported health problems in our study were eye related symptoms (37-59%) followed by skin diseases (24%) and LBP (23%). Eye related morbidity is the most common health hazard reported in several studies.[6,18] Thus, it highlights the need for use of proper eye protective devices while working. Paradoxically, respiratory complaints have been reported less among our study population. There could be several reasons for this. As explained above, workers with severe respiratory complaints may have left this profession. The other reason could be the fact that these workers were usually working in outdoor open space resulting in reduced exposure to dust/smoke. Also, we had not used any objective criteria for respiratory assessment such as spirometry, which have enabled us to diagnose at least mild cases of chronic obstructive pulmonary disease (COPD). As expected, the proportions of the welders with various health complaints increased with duration of exposure to hazard except for eye symptoms which were reported more in less exposure also. This could be because invisible ultraviolet light (UV) from the arc can cause “arc eye” or “welder's flash” after even a brief exposure (less than one minute).[6]

Limitations of the study

One of the limitations of the study was the cross-sectional design of the study. Moreover, results were based on observation over the study period, which may vary over different periods of time. Due to lack of comparison group, the results need to be interpreted with caution, in respect to association between hazard exposure and various ailments. Secondly, the assessment of exposure to various hazards was based on self-reporting by the workers, which could have been affected by the level of awareness among them. Lack of objective instruments such as ambient dust and smoke measurement, spirometry further contributed in underreporting of hazard exposure.

However, the study does point out important hazards to which the welders are exposed in this part of the world. The study deciphered some interesting findings such as association of duration of exposure to various hazards to occurrence of skin diseases among welders. To conclude, there is need for proper health and safety training of this economically productive group on workplace hazards and ergonomics to reduce work related morbidities. Use of correct and adequate personal protective devices at workplace needs to be stressed among this cadre of workers. More research is required to quantify the effects of welding process and duration of exposure on health.