Silicosis Among Engineered Stone Workers in Ontario, Canada: A Case Series of 20 Patients.

Abstract

Background: Silicosis is a preventable occupational lung disease caused by inhalation of respirable crystalline silica. Although traditionally associated with mining, it is increasingly recognized among workers who fabricate engineered stone, also referred to as artificial stone, for kitchen and other countertops. In Canada, updated surveillance data are limited, and no published case series have characterized engineered stone-associated silicosis.

Methods: We report a retrospective case series of 20 patients diagnosed with silicosis following occupational exposure to engineered stone in Ontario, Canada, between November 2015 and September 2025. Demographic, occupational, clinical, radiologic, and functional data were extracted from medical records. Continuous variables are reported as median and interquartile range (IQR).

Results: The median age at diagnosis was 52 years (IQR: 41.5-64.5), and all patients were male, predominantly immigrants from Southeast Asia. Median occupational exposure to silica was 19 years (IQR: 10.5-27.5). Although 80% reported respirator use, adherence was inconsistent, and workplace controls were often inadequate. Cough and dyspnea were the most common presenting symptoms (60% each), with a median diagnostic delay of 13.5 months. Imaging showed simple silicosis in 70% and progressive massive fibrosis in 30%. Pulmonary function tests demonstrated predominantly restrictive impairment with reduced diffusion capacity. Outcomes were significant, including 15% mortality, median age at death of 43 years, chronic hypoxia in 35%, and lung transplant referral in 30%.

Conclusions: Engineered stone-associated silicosis in Ontario is characterized by prolonged silica exposure, inadequate workplace protections, delayed diagnosis, and severe disease at presentation. These findings underscore the urgent need for strengthened regulatory measures to protect engineered stone workers: more effective occupational silica exposure controls, systematic respiratory health surveillance of workers at risk, and earlier recognition and diagnosis of silicosis.