For example, in the production of coke (a gray, hard, and porous coal-based fuel with high carbon content and few impurities), the blast furnace consumes as much as 96% of all the energy requirements in the integrated iron and steel industry to process the raw iron and steel bars into iron. Furthermore, in this process, the metallurgical coal is heated up and gases, oils, tar, and other by-products are produced that can cause lung cancer. These emissions are a concern not only to workers but also to nearby communities (Prabhu & Cilione, 1992). Other chemical hazards include zinc, hexavalent chromium, hydrochloric acid, and flux for collecting impurities from molten materials (Table 3; Fenton, 1996). Recently engineered nanoparticles have emerged and have many industrial applications. Although they are eective in many areas and economi- cally beneficial, the health, safety, and envi- ronmental impacts are largely unknown. The energy-intensive processes and opera- tions typical in the metallurgical industries are a result of processing large raw materials into smaller sizes and converting raw materi- als into finished products. It is not uncom- mon to use jaw crushers or gyratory and roll crushers in these operations, even though silica dust can be pervasive (Gupta & Yan, 2016). The operations that involve processes such as galvanizing; corrosion resistance; oxide removal; and solid and liquid separa- tion operations, filtration, and thickening units consume significant amounts of chemi- cals where aerosols can be emitted in large amounts (Table 3). The pickling units in some metal and met- allurgical facilities rely on acids to remove the oxides and scales from the incoming steel raw material slabs before they are sent to another unit for further processing (Fox et al., 1993). According to the U.S. Environmental Protec- tion Agency, the source of acid-mist emis- sions depends mainly on the configuration of the acid baths (i.e., surface area volume, tem- perature, local exhaust ventilation systems, degree of stirring or agitation). The resulting acid emissions are a health risk to workers and the environment. Additionally, oxygen deficiency hazards can be prevalent in some facilities (Stefana et al., 2018). These hazards should undergo a systematic assessment for prioritization and risk management to avoid asphyxiation
regarding chronic health eects, can be use- ful in this activity. There are multiple approaches from other federal and nonprofit agencies such as OSHA and the American Conference of Govern- mental Industrial Hygienists (ACGIH, 2023) in which multiple hazards can be assessed through exposure and OELs to determine risks in combination. Databases of injuries and illnesses are also useful tools to estimate the cost of medical care that results from acute or chronic injury and illness. One such database is the Estimated Costs of Occupa- tional Injuries and Illnesses and Estimated Impact on a Company’s Profitability Work- sheet from OSHA (n.d.) that can support exposure assessment goals. The worksheet estimates the risk of harm to employees and, with good historical records in industrial facilities, the tool can be good at character- izing risks for acute and chronic injuries. A caveat to the use of this approach is that a 3% profit margin must also be included in the characterization process. Results and Discussion The hazards identified and recognized in the literature, from walk-through audits and through previous experience in the industry, are profiled in Table 3. A basic information characterization shows that acid mists, heat stress, and ergonomic hazards are but a few of the hazards in the industry. A brief description of each hazard, task, and worker exposure is provided (Table 3). A strategy to assess, pri- oritize, and characterize risks of hazards relies on additional eort, including letter coding (Table 4). This strategy is aided by the estab- lishment of exposure assessment goals, expo- sure profiles, risk pathways, and exposure control categories for each hazard (Hager & Johnson, 2015; Reinhold & Tint, 2009). Chemical Hazards Typically, this industry can source its raw materials by importation of heavy iron bars and pellets (50–70% iron) using a basic oxy- gen furnace or by the reprocessing of scrap metal, mill scale, and steel slag that are recy- cled on-site using an electric arc furnace (Gal- laher & Depro, 2002; Supplemental Figure 1, www.neha.org/jeh-supplementals). The last two processes (i.e., forming and finishing) are energy-intensive, making the industry the 5th- largest consumer of energy in the U.S.
risk to employees, contractors, and people in nearby communities. When confronted with multiple chemical exposure scenarios, Equation 1 considers personal exposure samples and the OEL for each chemical to characterize and prioritize the hazard (ACGIH, 2023).
C1 C4 OEL1 OEL3 OEL3 OEL4 + C5 + Cn OEL5 OELn + C2 + C3 +
x =
(1)
Where Cn in the equation is the expo- sure concentration of chemical 1 and OELn is the corresponding permissible exposure limit (PEL). When x > 1, there is significant exceedance relative to OELs. When x < 1, the risks are low relative to OELs. Occupational Noise NIOSH has a recommended exposure limit for noise exposure of 85 dBA as an 8-hr time- weighted average (TWA). NIOSH estimates that a lifetime exposure of 40 working years would easily translate into an 8% excess risk of noise-induced hearing loss, with over 25% of the excess risk if exposures are ≥90 dBA of the OSHA PEL for an 8-hr TWA (Chan, 1998). A literature review concludes that >30 million people in the U.S. are exposed to excessive noise that might cause long- term noise-induced hearing loss (Chen et al., 2020; Farrell Luka & Akun, 2018; Royster, 2017). Occupational exposure to noise is not confined to the workplace and can have a spillover eect on the health impacts felt in communities. Symptoms of depression have been reported, along with paranoia, com- munication di«culties, suicide attempts, and lower quality of life in aected communities (Monazzam et al., 2019; Themann & Master- son, 2019; Yoon et al., 2014). Modernization of the workplace often includes engineered noise abatement meth- ods, but some automated systems are likely to create novel hazards that require new solu- tions to identify, characterize, and manage these hazards. In some areas of these metal and metallurgical industries, personal and area noise monitoring can range from 85 dBA to >100 dBA, respectively (Nyarubeli, 2018). Most workplace facilities that process steel coils of varying thicknesses are wrapped with several metal bands under high tension; this
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December 2023 • Journal of Environmental Health
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