Natural granite and marble contain modest amounts of crystalline silica. Engineered stone is manufactured differently: quartz is crushed to a fine powder, then bound with polyester resins and pigments, producing slabs that are typically more than 90 per cent crystalline silica. When a fabricator cuts, grinds or polishes such a slab into a kitchen countertop, the dust released is correspondingly more dangerous — and workers are also exposed to volatile organic compounds and metals from the resin system. That concentration explains the study's most alarming pattern: workers are being diagnosed young, after unusually short exposure, with disease that progresses fast and often occurs alongside other silica-associated conditions such as autoimmune disease and tuberculosis. Controlling the dust is technically straightforward — water-fed tools and proper ventilation — but the equipment is expensive to install and maintain, and enforcement in small fabrication shops is difficult.

India has the world's largest exposed workforce for this hazard — sandstone and quartz mining, stone crushing, agate polishing, slate pencil manufacture, foundries, ceramics and construction. Rajasthan alone has certified more than 22,000 silicosis cases and disbursed over 250 crore rupees in relief, following an intervention that began when the National Human Rights Commission took up the issue in 2009-10 and awarded relief in 48 cases including 22 deaths. A Comptroller and Auditor General report in 2018 found about 8,000 patients detected in the state in the two years to February 2017. The California findings matter because the same engineered-stone products, and the same small-workshop fabrication model, are spreading through urban Indian kitchens — importing a hazard whose consequences take years to surface and whose sufferers are typically informal workers outside any factory inspectorate's reach.