Workplace Occup Environ Med: first published as 10.1136/oemed-2017-104428 on 7 September 2017. Downloaded from SHORT REPORT Artificial stone-associated silicosis: a rapidly emerging occupational lung disease Ryan F Hoy,1 Timothy Baird,2 Gary Hammerschlag,3 David Hart,4 Anthony R Johnson,5 Paul King,6 Michael Putt,2 Deborah H Yates7 1Department of Epidemiology ABSTRACT What this paper adds and Preventive Medicine, School Introduction Artificial stone is an increasingly popular of Public Health and Preventive material used to fabricate kitchen and bathroom Medicine, Monash University, Fabrication of benchtops from artificial stone benchtops. Cutting and grinding artificial stone is ► Melbourne, Victoria, Australia may result in workers being exposed to high 2Department of Respiratory associated with generation of very high levels of levels of respirable crystalline silica. Medicine, Nambour General respirable crystalline silica, and the frequency of cases of The frequency of reported cases of silicosis Hospital, Nambour, Queensland, severe silicosis associated with this exposure is rapidly ► Australia associated with artificial stone work is 3 increasing. Department of Respiratory increasing significantly. Medicine, Royal Melbourne Aim To report the characteristics of a clinical series Artificial stone-associated silicosis is Hospital, Melbourne, Victoria, of Australian workers with artificial stone-associated ► characterised by a shorter latency and more Australia silicosis. 4Department of Respiratory rapid loss of lung function than chronic silicosis. Methods Respiratory physicians voluntarily reported Medicine, St Vincent’s Hospital, More cases of silicosis are likely to be cases of artificial stone-associated silicosis identified in ► Melbourne, Victoria, Australia diagnosed, and urgent action is required to 5Department of Thoracic their clinical practices. Physicians provided information increase awareness of the risk of silicosis in the Medicine, Liverpool Hospital, including occupational histories, respiratory function benchtop fabrication industry. Better measures Sydney, New South Wales, tests, chest radiology and histopathology reports, when Australia are needed to control dust levels, monitor and 6 available. Department of Respiratory protect workers in this industry. Medicine, Monash Medical Results Seven male patients were identified with Centre/ Monash University, a median age of 44 years (range 26–61). All were Clayton, Victoria, Australia 7 employed in small kitchen and bathroom benchtop Department of Thoracic Artificial stone is then sold to benchtop fabri- Medicine, St Vincent’s Hospital, fabrication businesses with an average of eight Sydney, New South Wales, employees (range 2–20). All workplaces primarily used cators, who use slabs to create benchtops based Australia artificial stone, and dust control measures were poor. on client specifications. Crystalline silica in arti- All patients were involved in dry cutting artificial stone. ficial stone becomes respirable when workers cut Correspondence to The median duration of exposure prior to symptoms and grind this using powerful tools. There is little Dr Ryan F Hoy, Department of was 7 years (range 4–10). Six patients demonstrated published information regarding levels of respi- Epidemiology and Preventive rable crystalline silica (RCS) generated from this Medicine, School of Public radiological features of progressive massive fibrosis. Health and Preventive Medicine, These individuals followed up over a median follow-up process. One study investigating the effectiveness http://oem.bmj.com/ Monash University, Melbourne period of 16 months (IQR 21 months) demonstrated of dust suppression measures when cutting artifi- Victoria 3004, Australia; rapid decline in prebronchodilator forced expiratory cial stone using a hand-operated circular saw noted DrRyanHoy@ gmail. com volume in 1 s of 386 mL/year (SD 204 mL) and forced that dry cutting generated an extremely high RCS 3 vital capacity of 448 mL/year (SD 312 mL). concentration of 44 mg/m over a 30 min sampling Received 14 March 2017 3 Revised 31 July 2017 Conclusions This series of silicosis in Australian period. This compares with 4.9 mg/m with wet 3 Accepted 13 August 2017 workers further demonstrates the risk-associated high- blade cutting and 0.6 mg/m with wet blade cutting 2 Published Online First silica content artificial stone. Effective dust control and in combination with local exhaust ventilation. on October 1, 2021 by guest. Protected copyright. 7 September 2017 health surveillance measures need to be stringently Short-term exposure to high concentrations of 3 implemented and enforced in this industry. RCS (>2 mg/m ) has an effect three times as great as a cumulative equivalent longer term exposure to lower levels.3 Freshly created dry, very fine silica particles produced by high-energy cutting have also BACKGROUND been demonstrated to have greater fibrogenicity Artificial stone (also referred to as engineered, compared with wet cutting of aged quartz, due to agglomerated or reconstituted stone and quartz reactive free radical species forming on the surface ► http:// dx. doi. org/ 10.1136/ conglomerate) is an increasingly popular and rela- of the particles.4 oemed- 2017- 104731 tively new building material used primarily in the Artificial stone became commercially available fabrication of kitchen and bathroom benchtops. in 1986, and the first report of artificial stone-as- Artificial stone is manufactured by many compa- sociated silicosis at a stonemasonry company was nies worldwide. Slabs of stone are formed by published from Italy in 2010.5 Since that time, there mixing finely crushed rock with a polymeric resin, have been an increasing number of cases reported 6–9 T Hoy RF,o cite: Baird T, then moulded into slabs and heat-cured. The silica from Spain, Israel and the USA. A 2011 Italian Hammerschlag G, et al. content of artificial stone is approximately 90%, far study of a workshop using mainly artificial stone Occup Environ Med higher than natural stones (marble 3%, granite 30% reported silicosis with a prevalence of 54.5% (6 out 2018;75:3–5. on average).1 11 workers).8 The risk of silicosis appears greatest Hoy RF, et al. Occup Environ Med 2018;75:3–5. doi:10.1136/oemed-2017-104428 3 Workplace Occup Environ Med: first published as 10.1136/oemed-2017-104428 on 7 September 2017. Downloaded from when dry cutting and polishing are performed. However, cases usage or had been involved in employer-organised health have also been noted to occur in workplaces where water jet surveillance. cutting and water dust suppression are used.6–8 Silicosis has been The median duration of exposure to artificial stone-associ- reported in workers involved in both workshop and home instal- ated dust prior to symptoms was 7.3 years (range 4–10 years). lation activities.8 Small businesses are frequently represented, All workers presented with symptoms of cough and progres- and inadequacies in performance of periodic preventive medical sively worsening shortness of breath on exertion. The duration examinations have been noted.7 Artificial stone has been avail- of symptoms prior to presentation to a respiratory physician able in Australia since the early 2000s. Here, we report the seven ranged from 6 months to 3 years. One patient also noted weight initial cases of silicosis associated with this material in Australia. loss and one experienced haemoptysis. CT was performed in all cases. In two cases the predomi- METHODS nant radiological finding was semiconfluent nodules in the mid and upper zones, maximal at apices and increased upper lobe Following the first reported case of artificial stone-associated interstitial markings. Extensive faint ground glass nodules were silicosis in Australia, further cases were notified voluntarily to present in two cases. Six cases with severe radiological abnor- the Thoracic Society of Australia and New Zealand’s Occupa- 10 malities were characterised by bilateral upper lobe fibrosis and tional Lung Disease Special Interest Group. Notifying respira- volume loss with reticulonodular and large confluent mass-like tory physicians were requested to provide information including densities, consistent with progressive massive fibrosis (PMF). occupational histories, respiratory function tests, chest radiology One case demonstrated rapid radiological progression over a and histopathology reports, when available. period of 4 years. The diagnosis of silicosis was based on a history of sufficient occupational silica exposure, radiological features consistent Lung biopsies were performed in five patients (four via with silicosis and lung histopathology (when available) demon- video-assisted thoracic surgery and one cryoprobe biopsy). The strating features of silicosis. Cases were diagnosed according to predominant histological finding was a histiocytic inflammatory recommended guidelines. Workplace exposure monitoring was infiltrate. Sclerotic nodules surrounded by histiocytes and histio- unfortunately not available. cytic aggregates with nodular areas were reported. In three cases, the presence of birefringent particles within some histiocytes was noted. Three patients had bronchoalveolar lavage performed RESULTS with a cell differential lymphocyte percentage ranging from 31% Between 2011 and 2016, seven cases of artificial stone-as- to 54%. sociated silicosis were identified by respiratory physicians in Respiratory function tests primarily demonstrated restrictive 1 3 3 Queensland, Victoria and