Home Email this page Print this page Bookmark this page Decrease font size Default font size Increase font size
Noise & Health  
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Email Alert *
Add to My List *
* Registration required (free)  

   Introduction and...
   Materials and Me...
   Results and Disc...
   Article Figures
   Article Tables

 Article Access Statistics
    PDF Downloaded36    
    Comments [Add]    
    Cited by others 3    

Recommend this journal


ARTICLE Table of Contents   
Year : 2010  |  Volume : 12  |  Issue : 46  |  Page : 37-48
Occupational exposure in small and medium scale industry with specific reference to heat and noise

1 Department of Industrial and Production Engineering, Dr. B R Ambedkar National Institute of Technology, Jalandhar, Punjab, India
2 Department of Physiology, All India Institute of Medical Sciences, New Delhi 110608, India

Click here for correspondence address and email
Date of Web Publication16-Feb-2010

This study was undertaken to assess heat and noise exposure and occupational safety practices in small and medium scale casting and forging units (SMEs) of Northern India. We conducted personal interviews of 350 male workers of these units through a comprehensive questionnaire and collected information on heat and noise exposure, use of protective equipment, sweat loss and water intake, working hour. The ambient wet bulb globe temperature (WBGT index) was measured using quest temp 34/36o area heat stress monitor. A-weighted Leq ambient noise was measured using a quest sound level meter "ANSI SI. 43-1997 (R 2002) type-1 model SOUNDPRO SE/DL". We also incorporated OSHA norms for hearing conservation which include - an exchange rate of 5dB(A), criterion level at 90dB(A), criterion time of eight hours, threshold level is equal to 80dB(A), upper limit is equal to 140dB(A) and with F/S response rate. Results of the study revealed that occupational heat exposure in melting, casting, forging and punching sections is high compared to ACGIH/NIOSH norms. Ambience noise in various sections like casting / molding, drop forging, cutting presses, punching, grinding and barreling process was found to be more than 90dB(A). About 95% of the workers suffered speech interference where as high noise annoyance was reported by only 20%. Overall, 68% workers were not using any personal protective equipment (PPE). The study concluded that the proportion of SME workers exposed to high level heat stress and noise (60 - 72 hrs/week) is high. The workers engaged in forging and grinding sections are more prone to noise induced hearing loss (NIHL) at higher frequencies as compared to workers of other sections. It is recommended that there is a strong need to implement the standard of working hours as well as heat stress and noise control measures.

Keywords: Occupational hazards, occupational health, occupational noise in SMEs

How to cite this article:
Singh LP, Bhardwaj A, Deepak KK. Occupational exposure in small and medium scale industry with specific reference to heat and noise. Noise Health 2010;12:37-48

How to cite this URL:
Singh LP, Bhardwaj A, Deepak KK. Occupational exposure in small and medium scale industry with specific reference to heat and noise. Noise Health [serial online] 2010 [cited 2018 Aug 14];12:37-48. Available from: http://www.noiseandhealth.org/text.asp?2010/12/46/37/59998

  Introduction and Literature Survey Top

Many of the developing countries like India are far behind in implementing occupational hygiene and pollution control measures at work sites. Occupational health and safety have not been at the top of small and medium scale manufacturing industry agenda in these countries. India is a population intensive country; labor available is cheap and illiterate, proper occupational hygiene practices are generally ignored at workplaces. Personal protective equipments (PPE) for workers are treated as luxuries rather than necessities and not sufficiently provided. Workers of these units (SMEs) are economic migrants from the eastern part of the country; they accept the working conditions as part of the job and do not demand better hygiene and PPE. Hence workers of these units are very much exposed to excessive amount of physical and chemical pollutants. This study was undertaken to assess heat and noise exposure and occupational safety and hygiene practices in casting and forging units (SMEs) of Northern India.

Indian Institute of Foundrymen (IIFM) represents the foundry industry and has more than 3500 members. The foundries support automobile, machine building, sanitary needs, households needs; 40% of the output of the foundries are for the automobile sector. The foundry industry has around 4500 foundries in India producing around seven million tons of castings many of them are tiny/small/medium scale. The industry gives employment to more than 500000 directly and three times indirectly. The Association of Indian forging industry (AIFI) represents the composition of the forging industry in our country. It can be categorized into four sectors - large, medium, small and tiny. As is the case world over, a major portion of this industry is made up of small and medium units / enterprises (SMEs). About 200 organized and 1000 unorganized forging units in the country spread across Pune, Chennai, Delhi and Punjab.

Steel forgings are an integral part of auto industry. The total capacity at present is estimated to be about 1.5 million tons per annum. As per estimates the industry provides direct employment to about 200,000 people, contributing directly to the livelihood of more than three quarter of a million people. The employer of small scale units are totally lagging behind in providing occupational health and safety to the workers, therefore the manpower employed in small scale casting and forging units are more exposed to occupational noise, heat stress, musculoskeletal strain and dust etc. The major occupational diseases of concern in these units are silicosis, musculo-skeletal injuries, pneumoconiosis, chronic obstructive lung diseases, and noise induced hearing loss (NIHL).

Scope of noise and heat exposure in casting and forging industry

Casting and forging workers are inevitably and continuously exposed to heat, noise, dust, fumes, gas and chemicals among other pollutants. The level of exposure to these hazards pollutants mainly depends upon the level of occupational hygiene and pollution control methods being implemented. Exposure to these pollutants can be reduced mainly by implementing pollution control methods and secondly by providing personal protective equipments to the exposed workers. Among all these occupational hazards, heat and noise are considered the prime factors affecting productivity/ performance of an individual. In the casting and forging industry, where heavy forging presses and drop hammers are used, noise is an integral part of operation. Hence it is being accepted as a necessary evil. The work place in most of the SMEs is very congested due to lack of availability of space. Simultaneous running of diverse machinery like drop hammers, blanking and punching presses, molding machine, pneumatic chippers grinders and barrels make the shops very noisy.

The main source of heat stress in hot forging industry is oil fired furnace in which the work piece is heated above 800 o C before it is transferred to forge hammer. Workers exposed to heat stress included: i) those transferring the hot work piece from furnace to forging die, ii) those who forge the work piece, iii) the hammer operators, iv) the furnace feeders. In casting units, the heat exposure is mainly in the melting area (cupola/induction furnaces), pouring process form cupola/induction furnace into crucible/ladle/mould. While working in heat the human body works at its best within a narrow temperature range. Shift of 2°C or more above or below the body's normal temperature of 37°C can begin inefficiencies.

Heat stress and human performance

The temperature of the environment is one of the factors affecting human performance. At body temperature substantially higher than the optimal levels (36.5°-37.5°C), both physical and mental performance deteriorates due to the complicated relationship of physiological and pathophysiological processes. A prolonged heat stress thus leads to loss of body fluid (de-hydration), which reduces performance, especially endurance. In addition, prolonged heat strain may impair mental and psychomotor functions, thereby affecting performance. In order to ensure optimal conditions for health and productivity, it becomes very important to assess the magnitude of the heat stress in the working environment and the worker's physiological reaction to it. In the last few decades, several studies have been carried out to assess occupational heat exposure and heat stress index. Most of the studies have been carried out in developed countries whereas casting and forging industry (SMEs) of under developed or developing countries like India are still far behind in this regard. In one study, the workers at a foundry were found more exposed to higher heat, noise, IR, UV radiations in comparison to workers in a bottling plant. [1]

The effects of metabolic heat can be reduced by providing rest periods after a regular interval of time. Failure to create reasonable comfortable working conditions in underground mining severely affects the productivity. [2] The spectral characteristics of muscles' sympathetic nerves activity (MSNA) are altered by whole body heating. However, heat stress-induced changes in MSNA do not parallel changes in systolic blood pressure variability. [3] The ISO 7243 standard and the ISO/DIS 7933 model are effective in predicting the excessive thermal strain of unacclimated men. [4] Heat can impair the performance of workers and should be considered a potential health hazard and production threat. [5] Productivity indicators pointed towards a poor performance with a correlation between productivity and thermal comfort. [6] Heat stress standard ISO 7243, based upon WBGT index, is suitable worldwide as a simple index for monitoring and assessing hot environments. The standard (index) has validity, reliability and usability. [7] A system of standards, a system of implementation and a culture that promotes health and safety that pervades internationally, will ensure healthy conditions. [8] The international standard for work in hot environments identifies maximum WBGT for continuous work (eight hours per day) and interrupted work (for example 75% work with 25% rest), beyond which a worker is at risk of heat exhaustion. [9]

Auditory, non-auditory effects of noise

Since the last two decades many authors have studied auditory as well as non-auditory effects of work place noise like psychological and cardiovascular effects. Chronic exposure to noise levels typical of many workplaces was associated with excess risk for acute myocardial infarction death. [10] The effect on blood pressure of occupational noise annoyance and its combined effect with social support at work, nightshift work, and work satisfaction were studied and an obvious effect of noise annoyance on diastolic blood pressure (DBP) was found. A long exposure to noise over 85 dB(A) might be a risk factor for high blood pressure (BP), and it possibly induces major increases of BP among sensitive individuals. [11],[12] A strict enforcement of current permissible exposure levels would not eliminate occupational hearing loss from industry. [13] The quality of life of industrial worker is one prime factor for production, which cannot be ignored. The revision of occupational Indian noise standard is recommended at par with International/European standards. [14]

An exposure to high intensity noise of 88-107 dB(A) six to eight hrs/day for long duration (10-15 years) brings about biochemical changes which make him prone to cardiovascular pathology. [15] Temporary threshold shift (TTS) recovery time is dependent on the magnitude of the initial hearing loss. Also, TTS driven by noise exposure is enhanced by heat and workload. [16] A continuous noise is a noise with peaks more often than once per second. Thus impulsive noise is assumed to have peaks occurring less often than once a second, and is limited to peak sound pressure levels of 140 dB. All continuous, intermittent, and impulsive noise between the levels of 80 and 130 dB(A) must be included in the exposure assessment. [17] Hearing protection must be provided at no cost to employees and must be worn by all workers exposed to a time weighted average (TWA) of 90 dB(A) and above. Hearing protection is also mandatory for those exposed to 85 dB(A) and above if they have not yet had a baseline audiogram. [17]

In one study, noise exposure of truck drivers of two different brands of truck was assessed and compared, and it was established that noise exposure was potentially hazardous to hearing. Authors gave serious consideration to work environment of truck drivers and proposed that the program for prevention of permanent hearing damage should be implemented. [18] In another study authors reported that impulse noise seemed to produce permanent threshold shifts at 4000 and 6000 Hz after a shorter duration of exposure than continuous steady state noise. Exposure to high levels of impulse noise (despite the use of ear protectors) is more detrimental to hearing than are high levels of continuous noise (even continuous with slightly impulsive features). Impulse noise seems to produce permanent threshold shifts at certain frequencies after a clearly shorter duration of exposure than continuous noise. The frequencies most sensitive to impulse noise are 4000 and 6000 Hz. Therefore, it is reasonable to assume that the qualities necessary for ear protectors to protect hearing from impulsive noise differ from those necessary to protect from continuous noise.

In future, it would be more realistic to not only study the effects of exposure to noise but also pay attention to subjective characteristics and individual factors of work conditions. [19] The workforce of two textile plants was found at high risk of developing noise induced hearing loss (NIHL) and other associated ailments. The author recommended that exposure limit stipulated by OSHA of 90 dB(A) for eight hrs/day shall be followed with caution. It was also recommended to establish hearing conservation programs including noise assessment, awareness among workers and audiometry. [20] Another study revealed that workers of small scale forging industry are highly exposed to high noise levels [more than 90 dB(A)], 60 to 72 h/wk without proper ear protection as compared to OSHA norms. It was recommended that SSI should be encouraged and facilitated to implement hearing conservation programmes under a good association with occupational health and environment professional. [21]

The Indian Factory Act-1948 lay down a limit of 90 dB(A) for eight hrs/ day but the Indian working hours are 48 hrs/week which leads to high noise exposure. Most of the workers are illiterate, semiliterate and not aware of the exposure norms and health hazardous effects of noise. [22],[23] Other authors reviewed a variety of studies on history of concerns about long working hours and the current scientific evidence regarding their effects on workers' health. It is reported that long working hours increases the risk for hypertension and cardiovascular disease along with relationships between long hours at work and musculoskeletal injuries, diabetes, and chronic infections. Evidence also suggests that overtime and extended work schedules can lead to depression and other psychological conditions. The ethical considerations regarding long working hours are to be thought of as questions about the type of society we want to create. Ethical implications of unconventional shift work and long work-hour schedules were considered in the study. A just and fair society will take actions to ensure that suitable jobs are available for as many people who want to work as possible, and that the jobs are safe and properly compensated, allowing not only for a beneficial work life, but also for a life that has time for rest, health, family, leisure activities and the attainment of one's personal values. [24]

  Materials and Methods Top

This study included randomly selected small and medium scale (SMEs) casting and forging units (each three) located in northern India. The approachability to the management of the organization and their willingness to participate in the study was more of a concern than randomization as work conditions of most casting and forging units in this region are almost similar. Hence convenience of approaching the management was the basis of selecting units for the study. The sizes of units vary from 50 to 1200 workers. The study has been conducted involving randomly selected 350 workers of these units. The questionnaire includes heat exposure, working hours, use of protective equipments, heavy work and awareness about benefits of PPEs, NIHL, noise annoyance etc. [Appendix-A].

The questionnaire was pretested before it was used to assess the information. As workers of these units are mostly illiterate or less educated, statements of the questionnaire were translated to both local language of the state i.e. Punjabi and Hindi. The interview was conducted by the authors in the local language and responses were entered in questionnaire.

Heat stress monitoring

Ambient temperature was measured using area heat stress monitor "Model Quest Temp 36/6º". The WBGT in index has been measured in various sections of these units. Results of the study revealed that occupational heat exposure is high as prescribed by NIOSH/ACGIH. Most of the work locations have an almost high temperature. The ambient temperature was recorded for 15 minutes each time on each work station and one long term recording for eight hours was done. At each section temperature was recorded at least five times at different locations where the movement of the workers was most frequent. There was hardly a difference of 0.5 to 1.5 degree between long term recoding and short term recording. The temperature near the worker's place of work and at five to 10 feet away differed by 0.5 to 1.5 degree at cupola furnace, induction furnace and oil fired furnace and 0.5 to 1.0 degree at drop forge section. The WBGT index at various sections like molding, melting/pouring, drop hammer, grinding and barreling sections was found very high than the permissible limits [Table 1],[Table 2],[Table 3].

Noise measurement

A weighted (Leq) ambient noise was assessed by using a quest sound level meter "model SOUNDPRO SP-DL-1-1/3". OSHA norms for hearing conservation were incorporated including an exchange rate of 5 dB(A), criterion level at 90 dB(A), criterion time of eight hours, threshold level equal to 80 dB(A), upper limit equal to 140 dB(A) and with F/S response rate.

In the molding section at different locations, noise was impulsive or intermittent; in grinding and melting sections there was almost steady noise. The sound pressure was recorded for 15 minutes each time on each work station and one long term recording for eight hours was done. At each section sound pressure was recorded at least four to five times at different locations where the movement of the workers was most frequent. There was hardly a difference of 0.5 to 1.0 dB(A) between long term recoding and short term recording. Most of the work locations have an almost steady noise production except the drop forge hammers, punching, blanking, trimming, and molding sections. Noise level at various sections like drop hammer, cutting / blanking presses, punching press, grinding, barreling and machine molding sections, was found greater than 90 dB(A) permissible limits [Table 4] and [Table 5].

Pure tone audiometry

A sample of 60 workers was deliberately selected from sections like forging, molding grinding, and tool room and invited to conduct pure tone audiometry at the institute laboratory. The hearing threshold was measured in an audiometric room at different frequencies. The workers were explained about the audiometry test and the same was conducted. Workers engaged in forging sections were found with higher loss of hearing as compared to workers engaged in other sections [Table 6] and [Table 7].

  Results and Discussion Top

The results of heat measurements reveal that WBGT index for temperature in casting units ranged from 32.17°C to 37.31°C and in forging units from 33.47°C to 38.03°C [Table 1] and [Table 2]. The main sources of heat in casting and forging units are cupola furnace, induction furnaces, oil fired furnace and heat treatment. In casting units the main sources of noise are machine molding, sand mulling/mixing, over-head cranes, fettling and pneumatic chipping, cupola-feeder and its motor drive. In forging units, drop hammers, punch and blank cutting press, grinders, barrels, vibrator, shot blasting machines are the sources of noise. In the grinding, finishing and shot blasting sections the noise was mainly continuous, however, in blanking, forging, punching/trimming, fettling and barreling processes the noise was intermittent or impulsive. The WBGT values observed in study are very high as compare to the permissible heat stress criteria [Table 3]. [9] In casting units, activities like; shoveling dry sand, machine and manual molding, carrying moulds, carrying molten metal form furnace to moulds and pouring of molten metal into moulds are all heavy work with higher relative metabolic rates (HRMR). In forging units the tasks of transferring hot work piece from furnace to forger, blanking and forging are heavy work activities; [9] workers engaged in these heavy activities are more prone to heat stress, heavy sweating and hence daily tiredness.

Ambient noise level (Leq) in casting and forging processes is shown in [Table 1] and [Table 5]. In casting units, the noise level varies from 88.9 dB(A) to 103.5 dB(A) and in forging units ranged from 86.5 and 110 dB(A) Leq which also exceeds the permissible limits (90 dB A) of OSHA. The daily exposure of workers in sections like blank cutting, forging, punching, machine molding, wheel and belt grinding, barreling section, broaching, gauging and sizing exceeds maximum exposure limit of 90 dB(A) specified by OSHA. Noise exposure in other work areas like nickel plating, machine section, die section is recorded less than 90 dB(A), but is quite higher than the limits used for assessment of noise for community noise. [20] OSHA norms are not valid in Indian SMEs because in most of these units workers work 10-12 hour/day and six days/week i.e. exposure time is 60 to72 hours per week. Most of the workers opted for two to four hrs/day over time i.e. 12 to 24 hours/week [Table 2] and this fact was also established by the managers of the plants. Therefore workers are under total exposure of 20 to 32 hour per week (i.e. 50 to 80%) higher than work exposure time standards (40 hrs per week) in USA or European countries. [21],[22],[23]

The overall noise exposure of casting workers is relatively lesser than forging workers; the casting workers are, however, more exposed to heat stress. Workers of casting processes mainly ignore noise hazards and thus the use of protective equipment at the same time. Workers of forging units accept noise as an integral part of the job.

Subjective responses

The percentages of responses collected from personal interviews are shown in [Table 8]. About 75% of workers are supposed to lift heavy load during their work. This kind of job requirement with metabolic heat production also makes considerable addition to heat stress. Around 85% of the workers reported unnecessary tiredness (of various levels) after working. The overall level of un-necessary tiredness (on five point rating scale) was 1.8. About 80% workers reported heavy sweating during work hours along with water intake of more than four liters /day and overall level of sweating was 3.75 (on five point rating scale). Subjective data also revealed that 85% of the workers do not take glucose/salt with water during work schedule. It is very obvious that mere water intake without salt or glucose is not sufficient to compensate for sweat (salt) loss. Although management of a few units had offered to provide lemon and salt water in place of tea, the workers preferred to tea. Interviews with workers revealed that un-necessary tiredness is very common and more among workers engaged in i) forging, ii) transferring hot work piece from furnace to forger, iii) molding, iv) molten metal pouring man, v) cupola and induction furnace workers. The extent of tiredness was less among workers engaged in grinding, gas cutting/welding, tool room, maintenance and quality check. Hence workers engaged in forging and molding sections, cupola/ induction furnace are more prone to high level of heat stress since these workers are doing heavy work with very high WBGT index as compared to permissible criteria [Table 3]. Consequently, majority of the workers have reported un-necessary tiredness after working hours. The chronic effect of the same can lead to heat stroke and overall health degradation of workers.

Speech interference

As far as noise effects are concerned, speech interference was experienced by 95% workers, of which 40% reported 'always' - majority of them were engaged in forging, blanking, punching, trimming, barreling, broaching and grinding sections; 30% reported 'often' and were mainly engaged in machine molding, shot blasting, sizing gauging. Rest of the workers reported low speech interference and were engaged in tool room, nickel plating, quality and cupola/induction furnace operators. The overall level of speech interference was 2.9 (on five point rating scale).

Noise annoyance

Five per cent of the workers reported 'always' annoyed, 15% 'often', 42% 'sometimes', 10% workers 'seldom annoyed' and 28% 'never felt annoyed' by high noise levels. The overall level of noise annoyance on five scales was found to be 1.59. The less per cent of high annoyance is attributed to the two reasons; (a) workers have accepted noise as a part of their job, (b) workers get adapted to noisy work conditions with the increasing work exposure to high noise levels.

Majority of the workers who reported noise annoyance were with less than five years of work exposure, as long as exposure increases noise annoyance is reduced [Table 9]. Concurrent to increased adaptability, workers also undergo noise induced hearing loss (NIHL) which explains why workers feel less noise annoyance.

Hearing disability (NIHL)

A pure tone audiometry was conducted on a sample of 60 male workers of age group 30 to 35 years with experience of seven to 10 years, threshold level of both ears was checked [Table 6]. These workers were selected from forging, molding, grinding and other sections like broaching, shot blasting welding gauging sizing of these shops. Pure tone audiograms of workers engaged in sections like forging, molding, grinding and other sections [Figure 1]a, b. Audiograms of forging worker are significantly different from the others. Depression in audiogram shows that workers engaged in forging sections have high level of NIHL i.e. loss of hearing at frequencies 2 kHz, 3 kHz, 4 kHz 6 kHz and 8 kHz as compared to the workers engaged in molding, grinding and other sections. There is moderate to severe loss of hearing threshold (dB) in at higher frequencies however minor to moderate loss at lower frequencies. Workers of other sections were found with minor loss of hearing threshold. The grinding and forging are found to be more hazardous than other processes. It is already mentioned that majority of the workers do not use PPE; managements of these units also do not bother much about the protection of workers' ears. Hence hearing health is prominently ignored in these SMEs. There is a strong need to provide proper ear protection and noise isolation in these units.

Although 70% workers reported that they are aware of the benefits of using PPE subjective data also revealed that a big proportion (68%) of workers did not use PPE in both casting and forging units [Figure 2]. Only 25% of the workers wear dungarees, 45% use gloves, 35% report using eye protection (goggles) and 25% workers wear gum shoes or boots and nose mask was used by 40% workers. The ear protection was found to be the least preferred or ever used PPE, and only to 12% workers used it.

The reasons stated for not using PPE: 35% did not feel uncomfortable, 10% are not used towearing the same, 30% admitted to egligence and around 25% said management did not provide PPE at work place [Figure 3]. Workers working without PPE in casting and forging processes are shown in [Figure 4]. About 85% of workers reported that management did not enforce use of PPE; in most small scale units management did not even bother about it. Reason, management concentrates on executing the orders and shipments. Another significant factor is that workers in small scale casting and forging units also work under contractors who ignore this aspect. It is also true that workers do not expect health and safety care from the management; rather they have accepted hazards conditions as a part of their job as well as life. Whatever the reason may be, workers do not use PPE; thus it is obvious that majority of the workers are directly exposed to noise, temperature / heat radiations and dust also. Around 85% of workers work more than eight hrs/day with additional over time of two to four hrs/day (12 -24 hrs/week) which is a major factor contributing towards very high noise exposure (more than the OSHA norms). Such long working hours may increase risk of hypertension and cardiovascular disease along musculoskeletal injuries, depression and other psychological conditions. [23] This gives sufficient support to consider ethical considerations regarding long working hours and poses a new question about the type of society we want to create and the ethical implication on unconventional shift work and long work-hour schedules. The prevailing performance standards in SMEs generally do not include sufficient rest allowances. Thus there is also a strong need to set reasonable performance standards for various activities with appropriate rest allowances.

Satisfaction level of workers

As far as overall satisfaction level of workers with respect to work environment was concerned, it was 2.45 on a five point rating scale. Within the scenario of un-employment workers are scared of losing the job. They have accustomed themselves to the working conditions and do not expect much health and safety facilities from the management; rather they felt satisfied with the job in hand. Whole data reveals that, the workers engaged in various processes of casting and hot forging processes of SMEs units are highly exposed heat stress, as well as noise. Management of the SMEs are more focused on overall production and quality for fetching more and more orders from their customers at the cost of occupational health and safety of workers. The crux of the present study can be enumerated as "managements of SMEs are not giving due consideration to health and safety of workers", but ignoring the health and safety factors. In other words management is defying the fact that "only a healthy worker can give better quality with best output than any unhealthy worker".

  Conclusions Top

Recent industrialization and globalization have changed the Indian occupational morbidity drastically. This transition poses challenges to health care system with new concepts of environmental legislation, new safety regulations and ethical issues. Traditionally, labor oriented markets are changing towards more automation and mechanization but general awareness about the occupational safety, occupational and environmental health hazard is missing. Due to lack of education, unawareness of the hazards of their occupations, general backwardness in sanitation, poor nutrition and climatic proneness of this geographic region to epidemics aggravates their health hazards from work environment. In India, SMEs are still far behind in implementing occupational health and safety programs. The study specifically focused on casting and forging units.

The crux of the present study can be concluded as follows:

  1. Workers of both casting and forging units are highly exposed to heat stress and high noise levels, 60 - 72 hrs/week without using PPE. These long working hours violate ethical implications of the work schedule.
  2. Workers engaged in forging and grinding sections are more prone to NIHL at higher frequencies among workers in other sections.
  3. Majority of the workers do not wear PPE mainly due to negligence or discomfort or not being provided with PPE by the management.
  4. There is a strong need to implement the working hour's standard and heat stress and noise control measures. It is recommended that the hearing conservation program should be implemented under the aegis of some NGOs.
  5. SMEs should be encouraged to implement heat stress management and hearing conservation programs. Workers should be motivated through education to use PPE for heat stress and hazards of noise exposure.

  Acknowledgment Top

Authors acknowledge the co-operation and help extended by the management and workers of casting and forging units in conducting personal interviews, measuring heat stress index and noise levels at each section very thoroughly.

  References Top

1.Gomes J, Lloyd O, Norman N. The health of the workers in a rapidly developing country: effects of occupational exposure to noise and heat. Occup Med 2002;52:121-8.  Back to cited text no. 1      
2.Mustafa O, Saim S, Seyhan O. A study of heat stress parameters at Kozlu coalmine: Turkey. J Occup Health 2005:47:343-5.  Back to cited text no. 2      
3.Jian Cui, Rong Zhang, Thad E. Wilson, Crandall CG, Spectral analysis of muscle sympathetic nerve activity in heat-stressed humans. Am J Physiol Heart Circ Physiol 286: H1101-H1106, 2004.  Back to cited text no. 3      
4.Juhani S, Ilmarinen R, Korhonen O. An evaluation of heat stress indices (ISO 7243, ISO/DIS 7933) in the prediction of heat strain in unacclimated men. Int. Arch Occup Environ Health 1991:63:39-4.   Back to cited text no. 4      
5.Bates G, Veronica M. The effects of the thermal environment on health and productivity. IOHA 2005 PILANESBERG. Paper B2-3.  Back to cited text no. 5      
6.Thatcher A, James J, Todd A. Ergonomics analysis of the thermal environment: a case study for companies in the alpaca textile sector of Arequipa - Peru. Proceedings of "The Fourth International Cyberspace Conference on Ergonomics. Johannesburg. 2005 CybErg.  Back to cited text no. 6      
7.Parsons K. Eat Stress Standard ISO 7243 and its Global Application: Review Article. Ind Health 2006;44:368-79.  Back to cited text no. 7  [PUBMED]  [FULLTEXT]  
8.Parsons KC. Industrial Health for All. Appropriate Physical Environments, Inclusive Design, and Standards that are truly International. Industrial Health 2008; 46:195-7  Back to cited text no. 8      
9.American Conference of Governmental Industrial Hygienists (ACGIH). Documentation of the Threshold Limit Values and Biological Exposure Limits, Notice of Intended Changes. Cincinnati, Ohio. ACGIH 2001.  Back to cited text no. 9      
10.Hugh WD, Kay T, Kennedy SM, Murray RH, Clyde H, Paul AD. Occupational exposure to noise and mortality from acute myocardial infarction. Epidemiology 2005;16:1  Back to cited text no. 10      
11.Peter L, Josef H, Walter WK. Work noise annoyance and blood pressure: combined effects with stressful working conditions. Int Arch Occup Environ Health 1993;65:23-8.  Back to cited text no. 11      
12.Thierry L, Christiane F, Marie-C, Jacquinet-Salord. Length of occupational noise exposure and blood pressure. Int Arch Occup Environ Health 1992;63:369-372.  Back to cited text no. 12      
13.Hetu R. The risk of hearing loss from exposure to noise. Groupe d'acoustique de l'université de Montréal 1994.  Back to cited text no. 13      
14.Kisku GC, Bhargwa SK. Assessment of noise level; of medium scale thermal power plant. Indian Occupational and Environmental Medicine Dec Vol. 10-Issue 3, 133-139.   Back to cited text no. 14      
15.Rai RM, Singh AP, Upadhyay TN, Patil SK, Nayar HS. Biochemical Effects of chronic exposure to noise in man. Int Arch Occup Environ Health 1981;48:331-7.  Back to cited text no. 15      
16.Chiu-Jong C, Yu-Tung D, Yin-Min S, Yi-Chang, Yow JJ. Evaluation of auditory fatigue in combined noise, heat and workload exposure. Industrial Health 2007;45:527-34.  Back to cited text no. 16      
17.OSHA's Noise Standard Defines Hazard, Protection, Resource Guide 2000.  Back to cited text no. 17      
18.Dawid J, van DH, Francois JR. Noise exposure of truck drivers: a comparative study. Am Ind Hyg Assoc J 1996:57:564-6.   Back to cited text no. 18      
19.Mantysalo S, Vouri J. Effects of Impulse noise and continuous steady state noise on hearing. Br J Ind Med 1984;41:122-32.  Back to cited text no. 19      
20.Bedi R. Evaluation of occupational environment in two textile plants in northern india with specific reference to noise. Ind Health 2006;44:112-6.  Back to cited text no. 20      
21.Singh LP, Bhardwaj A, Deepak KK, Bedi R. Occupational Noise Exposure in Small Scale Hand Tools Manufacturing (Forging) Industry (SSI) in Northern India. Industrial Health 2009, 47, 423-430.  Back to cited text no. 21      
22.Bedi R, Shukla DK, Sachdeva A. Effects of Impact noise on humans - a case study of drop forge hammer. Proceeding of 7 th Int. Symposium transport Noise and vibration, St. Petersburg: Russisa; 2004.  Back to cited text no. 22      
23.IS:7194-(1994) Indian Standard, assessment of noise during work for hearing conservation purpose. (First revision) BIS India.  Back to cited text no. 23      
24.Allard E. Dembe. Ethical Issues Relating to the Health Effects of Long Working Hours. Journal of Business Ethics. Springer; 2008. p. 10551-008-9700-9.  Back to cited text no. 24      

Correspondence Address:
Lakhwinder Pal Singh
Department of Industrial &Production Engineering, Dr B R Ambedkar National Institute of Technology, Jalandhar-144 011
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1463-1741.59998

Rights and Permissions


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9]

This article has been cited by
1 Occupational noise-induced hearing loss in indian steel industry workers: An exploratory study
Singh, L.P. and Bhardwaj, A. and Deepak, K.K.
Human Factors. 2013; 55(2): 411-424
2 Hearing protection use in manufacturing workers: A qualitative study
Reddy, R.K. and Welch, D. and Thorne, P. and Ameratunga, S.
Noise and Health. 2012; 14(59): 202-209
3 Occupational health hazards in small scale steel manufacturing industries: A case study
Chohan, J.S. and Bilga, P.S.
International Journal of Manufacturing Technology and Management. 2011; 24(1-4): 182-192