Assessment of Workplace Air Concentrations of Indium Dust in an Indium‐recycling Plant

Miyauchi, Hiroyuki; Minozoe, Aoi; Tanaka, Shigeru; Tanaka, Akiyo; Hirata, Miyuki; Nakaza, Masahiro; Arito, Heihachiro; Eitaki, Yoko; Nakano, Makiko; Omae, Kazuyuki

doi:10.1539/joh.11-0233-oa

Cited by 16 publications

(13 citation statements)

References 9 publications

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“…(48,69,70) The published data clearly indicate that, if not well controlled, indium exposure can exceed recommended exposure limits in the manufacturing of ITO sputter targets, in the handling of indium oxide and indium hydroxide, and in reclaiming indium from recycled materials. (10,68,69) Little has been known about indium exposure to workers in downstream applications of ITO and other indium materials. The results presented here begin to address this data gap by identifying other activities that are likely (if not well controlled) and unlikely to result in worker exposure to indium.…”

Section: Discussionmentioning

confidence: 99%

Use of and Occupational Exposure to Indium in the United States

Hines

Roberts

Andrews

et al. 2013

Journal of Occupational and Environmental Hygiene

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Indium use has increased greatly in the past decade in parallel with the growth of flat-panel displays, touchscreens, optoelectronic devices, and photovoltaic cells. Much of this growth has been in the use of indium tin oxide (ITO). This increased use has resulted in more frequent and intense exposure of workers to indium. Starting with case reports and followed by epidemiological studies, exposure to ITO has been linked to serious and sometimes fatal lung disease in workers. Much of this research was conducted in facilities that process sintered ITO, including manufacture, grinding, and indium reclamation from waste material. Little has been known about indium exposure to workers in downstream applications. In 2009–2011, the National Institute for Occupational Safety and Health (NIOSH) contacted 89 potential indium-using companies; 65 (73%) responded, and 43 of the 65 responders used an indium material. Our objective was to identify current workplace applications of indium materials, tasks with potential indium exposure, and exposure controls being used. Air sampling for indium was either conducted by NIOSH or companies provided their data for a total of 63 air samples (41 personal, 22 area) across 10 companies. Indium exposure exceeded the NIOSH recommended exposure limit (REL) of 0.1 mg/m3 for certain methods of resurfacing ITO sputter targets, cleaning sputter chamber interiors, and in manufacturing some inorganic indium compounds. Indium air concentrations were low in sputter target bonding with indium solder, backside thinning and polishing of fabricated indium phosphide-based semiconductor devices, metal alloy production, and in making indium-based solder pastes. Exposure controls such as containment, local exhaust ventilation (LEV), and tool-mounted LEV can be effective at reducing exposure. In conclusion, occupational hygienists should be aware that the manufacture and use of indium materials can result in indium air concentrations that exceed the NIOSH REL. Given recent findings of adverse health effects in workers, research is needed to determine if the current REL sufficiently protects workers against indium-related diseases.

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Section: Discussionmentioning

confidence: 99%

Use of and Occupational Exposure to Indium in the United States

Hines

Roberts

Andrews

et al. 2013

Journal of Occupational and Environmental Hygiene

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“…Workers engaged in the production and reclamation of ITO are potentially exposed to indium having a variety of chemical forms (Choi et al, 2015; Chonan et al, 2007; Cummings et al, 2010; Hamaguchi et al, 2008; Homma et al, 2003, 2005; Liu et al, 2012; Miyauchi et al, 2012; Nakano et al, 2009). Our in vitro experiments demonstrated that indium was released from all tested study materials using SUF or PSF artificial lung fluids and that observed differences in dissolution rates could be attributed to the chemical form of indium in the dust.…”

Section: Discussionmentioning

confidence: 99%

“…Off-specification or worn product and other indium-containing scrap materials are recycled to reclaim indium (Cummings et al, 2010; Miyauchi et al, 2012). During the production and reclamation of ITO, workers may inhale airborne dusts that contain indium metal, indium salts, indium hydroxide (In(OH) 3 ), indium oxide (In 2 O 3 ) and/or ITO (Choi et al, 2015; Chonan et al, 2007; Cummings et al, 2010; Hamaguchi et al, 2008; Homma et al, 2003, 2005; Liu et al, 2012; Miyauchi et al, 2012; Nakano et al, 2009). Once inhaled, indium clears from the body slowly over time and hence persists in the body even after exposure ceases (Amata et al, 2015; Liu et al, 2016; Nakano et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Application of the ICRP respiratory tract model to estimate pulmonary retention of industrially sampled indium-containing dusts

Stefaniak

Virji

Badding

et al. 2017

Inhalation Toxicology

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Inhalation of indium-containing dusts is associated with the development of indium lung disease. Workers may be exposed to several different chemical forms of indium; however, their lung dosimetry is not fully understood. We characterized the physicochemical properties and measured the lung dissolution kinetics of eight indium-containing dusts. Indium dissolution rates in artificial lung fluids spanned two orders of magnitude. We used the International Commission on Radiological Protection (ICRP) human respiratory model (HRTM) to estimate pulmonary indium deposition, retention and biokinetic clearance to blood. For a two-year (median workforce tenure at facility) exposure to respirable-sized particles of the indium materials, modeled indium clearance (>99.99% removed) from the alveolar-interstitial compartment was slow for all dusts; salts would clear in 4 years, sintered indium–tin oxide (ITO) would clear in 9 years, and indium oxide would require 48 years. For this scenario, the ICRP HRTM predicted that indium translocated to blood would be present in that compartment for 3.5–18 years after cessation of exposure, depending on the chemical form. For a 40-year exposure (working lifetime), clearance from the alveolar–interstitial compartment would require 5, 10 and 60 years for indium salts, sintered ITO and indium oxide, respectively and indium would be present in blood for 5–53 years after exposure. Consideration of differences in chemical forms of indium, dissolution rates, alveolar clearance and residence time in blood should be included in exposure assessment and epidemiological studies that rely on measures of total indium in air or blood to derive risk estimates.

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“…45 In 2008, workplaces that involved recycling processes were required to improve the work environment. 48 Prevalence of both In-S level ≥3 µg/L and/ or serum KL-6 > 500 U/ml on the Specialized Medical Examination for indium-exposed workers by PHSCS was 189/7412 (2.5% in 2013), 166/8416 (2.0% in 2014), 178/9086 (2.0% in 2015), and 174/9170 (1.9% in 2016). The 1.9% prevalence of indium and indium compounds was slightly higher than the 1.6% for all specified chemical substances.…”

Section: Post-regulation Period Since 2013mentioning

confidence: 90%

“…Among indium‐exposed workers in the baseline study, prevalence of In‐S level ≥3 µg/L and of serum KL‐6 > 500 U/ml were 190/424 (45%) and 124/549 (23%), respectively . In 2008, workplaces that involved recycling processes were required to improve the work environment . Prevalence of both In‐S level ≥3 µg/L and/or serum KL‐6 > 500 U/ml on the Specialized Medical Examination for indium‐exposed workers by PHSCS was 189/7412 (2.5% in 2013), 166/8416 (2.0% in 2014), 178/9086 (2.0% in 2015), and 174/9170 (1.9% in 2016).…”

Section: Indium Lungmentioning

confidence: 99%

Update of occupational lung disease

Suganuma

Natori

Kurosawa

et al. 2019

Journal of Occupational Health

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Objective Occupational Lung Disease is an oldest but still a biggest problem in occupational health. Methods Steering Committee members of the Japan Society for Occupational Health (JSOH) Occupational Lung Disease Study Group selected and summarized current topics on occupational lung diseases based on expert opinion, as informed by governmental regulation, public health concerns, and frequently discussed in related academic conferences. Results The topics included in this review are professional education in medical screening skills, 2014 update of Helsinki Criteria, respiratory diseases found in the earthquake and tsunami affected regions, newly recognized occupational lung diseases, and potential respiratory health hazards. Discussions Although occupational lung diseases seem to stay as one of the major concerns in occupational health, screening tools and control measures are standardized for the better prevention of the diseases. As this health problem usually occurs in where the most actively economically developing area is, the patients tend to increase in emerging economic powers with huge population.

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Assessment of Workplace Air Concentrations of Indium Dust in an Indium‐recycling Plant

Cited by 16 publications

References 9 publications

Use of and Occupational Exposure to Indium in the United States

Use of and Occupational Exposure to Indium in the United States

Application of the ICRP respiratory tract model to estimate pulmonary retention of industrially sampled indium-containing dusts

Update of occupational lung disease

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