Occupational Heat Stress Impacts on Health and Productivity in a Steel Industry in Southern India
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View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Safety and Health at Work xxx (2016) 1e6 Contents lists available at ScienceDirect Safety and Health at Work journal homepage: www.e-shaw.org Original Article Occupational Heat Stress Impacts on Health and Productivity in a Steel Industry in Southern India Manikandan Krishnamurthy, Paramesh Ramalingam, Kumaravel Perumal, Latha Perumal Kamalakannan, Jeremiah Chinnadurai, Rekha Shanmugam, Krishnan Srinivasan, Vidhya Venugopal* Department of Environmental Health Engineering, Sri Ramachandra University, Tamil Nadu, India article info abstract Article history: Background: Workers laboring in steel industries in tropical settings with high ambient temperatures are Received 29 July 2015 subjected to thermally stressful environments that can create well-known risks of heat-related illnesses Received in revised form and limit workers’ productivity. 4 August 2016 Methods: A cross-sectional study undertaken in a steel industry in a city nicknamed “Steel City” in Accepted 5 August 2016 Southern India assessed thermal stress by wet bulb globe temperature (WBGT) and level of dehydration Available online xxx from urine color and urine specific gravity. A structured questionnaire captured self-reported heat- related health symptoms of workers. Keywords: climate change Results: Some 90% WBGT measurements were higher than recommended threshold limit values (27.2 e health risks 41.7 C) for heavy and moderate workloads and radiational heat from processes were very high in occupational heat stress blooming-mill/coke-oven (67.6 C globe temperature). Widespread heat-related health concerns were productivity loss prevalent among workers, including excessive sweating, fatigue, and tiredness reported by 50% workers. steel industry Productivity loss was significantly reported high in workers with direct heat exposures compared to those with indirect heat exposures (c2 ¼ 26.1258, degrees of freedom ¼ 1, p < 0.001). Change in urine color was 7.4 times higher among workers exposed to WBGTs above threshold limit values (TLVs). Conclusion: Preliminary evidence shows that high heat exposures and heavy workload adversely affect the workers’ health and reduce their work capacities. Health and productivity risks in developing tropical country work settings can be further aggravated by the predicted temperature rise due to climate change, without appropriate interventions. Apart from industries enhancing welfare facilities and designing control interventions, further physiological studies with a seasonal approach and interventional studies are needed to strengthen evidence for developing comprehensive policies to protect workers employed in high heat industries. Ó 2016, Occupational Safety and Health Research Institute. Published by Elsevier. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 1. Introduction occupational health and safety risks to the exposed population in low and middle income countries [4,5]. Heat is one of the physical hazards that can cause health problems Climate change, as an environmental health-risk component is a in the workplace [1,2] and one of the most important and common newly recognized phenomenon, with global scope, operating over occupational health problems in workplaces is inappropriate thermal long time periods and affecting an unusually wide range of health conditions that can impact the health and productivities of workers outcomes [7]. Climate change is an added risk component due to [3e6]. Daily heat exposure during the hot season in tropical and the predicted rise in air temperatures and humidity as part of local subtropical parts of the world is a problem particularly for people climate change that shall further increase the existing occupational working in jobs that cannot be, or are not cooled by air conditioning health risks due to heat exposures [8]. Several direct and indirect or other technical methods. Tropical climates with high ambient health impacts of global and local climate change have been temperature and humidity may therefore pose higher heat-related documented or forecasted [9,10]. * Corresponding author. Department of Environmental Health Engineering, Sri Ramachandra University, No.1, Sri Ramachandra Nagar, Porur, Chennai, Tamil Nadu, India, 600116. E-mail address: [email protected] (V. Venugopal). 2093-7911/$ e see front matter Ó 2016, Occupational Safety and Health Research Institute. Published by Elsevier. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). http://dx.doi.org/10.1016/j.shaw.2016.08.005 Please cite this article in press as: Krishnamurthy M, et al., Occupational Heat Stress Impacts on Health and Productivity in a Steel Industry in Southern India, Safety and Health at Work (2016), http://dx.doi.org/10.1016/j.shaw.2016.08.005 2 Saf Health Work 2016;-:1e6 People who carry out heavy physical labor as a part of their daily generated radiant heat was observed, especially during charging jobs (or household activities) are at particular risk, as the physical and discharging of coal and coke from the furnace. Radiant heat activity itself causes high internal heat production which must was also predominant in the cooling bed area where the coke was be released to avoid heat strain health symptoms, as it may lead cooled for further processes. Coke making consisted of two pro- to life-threatening “severe hyperpyrexia” (core body temper- cesses, i.e., primary steel making and the secondary steel making ature > 40.6C) [1]. When air temperature exceeds 37C, evapora- process. In the primary steel making process, atmospheric oxygen tion of sweat becomes one of the primary mechanisms to cool the is blown into an initial charge containing hot metal, preheated solid body that can be strongly impaired by high air humidity. This heat scrap, and fluxes in the energy optimizing furnace (EOF) where the cannot easily be transferred from the body when the work envi- slag is formed and carbon, silicon, and phosphorus are eliminated ronment is hot or when the air is humid and evaporation of sweat is depending on the steel grade. Here, the workers had to manually inefficient [11], which creates health impacts and loss of work ca- supply oxygen continuously in to the furnace, as shown in Fig. 1.In pacity among the exposed [1]. the continuous casting mill (CCM), the molten steel from the EOF is For workers to protect themselves from the heat, the simplest solidified into a “semi-finished” billet, bloom, or slab for subse- way is to slow down work and take more and longer breaks [1], but quent rolling in the finishing mills. The blooming mill, an inter- this reduces the daily work productivity of the workers and is also mediate link between the steel casting shops and the rolling shops, not possible in certain jobs [2]. The other mechanism is to cool turns out the semi-finished product of blooms out of steel ingots of themselves, but this is difficult to achieve in many Indian work large cross sections and these are sent to bar and rod mills (BRM). In settings by air conditioning or cooling systems. Asia is at particular BRM, the final process of steel making, the “semi-finished” billet or risk, as confirmed by a health impact assessment for the World bloom is size reduced to different dimensions based on the product Health Organization [12]. India is a country with hot summer requirements. seasons and millions of poor workers are likely to be affected by excessive workplace heat [13], with consequent health risks, and reduced productivity and daily incomes [14,15]. The adverse im- 2.2. Methodology pacts of heat on health and work capacity (and productivity) studied at an individual level [5,11,13,16,17] stands as evidence for Area heat stress was measured in 49 work locations throughout this occupational health risk posed by the workers. With the pre- the industry where workers were exposed to heat. The quantitative dicted rise in temperature and anticipated economic loss due to the heat measurements were conducted according to the protocols changing climate scenario in some geographical locations [18],it recommended by the National Institute for Occupational Safety and becomes imperative that attention be focused on conducting more Health [21]. Locations for measurements were selected based on such studies in the South Asian region of the globe [19]. the initial walkthrough survey that was conducted before the start The need to generate research evidence and implement sus- of the monitoring; these included indoor locations with and tainable intervention techniques to reduce workplace heat stress to without exposures to process-generated heat exposure, and out- prevent health and productivity risks for millions of poor working door and semi outdoor locations. Since most of the workplace lo- people employed in high heat environments is warranted. With cations within the industry were not air conditioned, and therefore fl this background, the present study was carried out by the in- likely to be in uenced by outside temperature and time of day/ vestigators in a steel industry in India to understand the impacts of season, measurements were always made during the hottest part e heat stress on the health and productivity of workers working in (10:00 AM 14:30 PM) of the day. For assessment of exposure to heat high heat industries, the results of which are presented in this stress,