Jacinta Bowler
Jacinta Bowler is a science journalist at Cosmos.
They were published in the Best Australian Science Writing 2023.
The deadly lung disease silicosis is becoming more prevalent in Australian workers – particularly in the ‘engineered stone’ industry. But new research suggests it may not just be the maligned silica – or quartz – to blame.
This raises important questions about use of alternatives for the popular stone benchtops.
“Many countries worldwide have witnessed the re-emergence of silicosis, a historical occupational lung disease that should have been extinct,” the researchers from Adelaide and Hobart write in a new paper in the journal Respirology.
“This is likely due to the emergence, and increasing popularity of, high-silica containing engineered stone products in the manufacturing industry.”
“The outcomes of this study have important implications for future regulation of engineered stone products as they challenge the common view that reducing the crystalline silica alone will eliminate disease risk,” the researchers conclude.
While high-silica engineered stone is slowly being phased out across the nation, alternatives with less silica are starting to emerge.
However, when researchers analysed fine particles of dust from 50 resin based engineered stones, three natural stones and two non-resin-based materials, they found that it was not just the silica that was causing issues.
In the cell-based study, immune cells called macrophages and lung cells were used to test for inflammation and cytotoxicity.
“From an ethical (and moral) perspective, we cannot expose humans to any hazards for research purposes. So really human lung cells grown in vitro are the next best thing,” lead author Dr Chandnee Ramkissoon from the University of Adelaide, told Cosmos.
“They are a simple and powerful tool that enable us to explore with great accuracy how the lung would perform upon exposure to different hazards.”
The team found that while silica caused inflammation, cobalt and aluminium were also a problem.
“Metals like cobalt and aluminium are commonly present during artificial stone making. They can be present in raw materials or be added in for example as pigments used to give colour to stones. These metals have an established link to adverse respiratory health. In particular, excessive exposure to heavy metals like cobalt can cause respiratory disorders including bronchial asthma, chronic bronchitis and pulmonary fibrosis,” said Ramkissoon.
“Our results showed that higher silica content was associated with more inflammation. However, their metallic components could also be hazardous to lung health.”
The team stress that more urgent research needs to be done to find out which – if any – engineered stones are safe for the workers.
“We do need to tread carefully and allow future (urgent) research to evidence the safety,” said Ramkissoon.
“Given the enormous harm that engineered stone has caused, and is continuing to cause, stone benchtop industry workers, it is crucial that we investigate the safety of these alternative products.”
Last month Safe Work Australia released a ‘regulation impact statement’ recommending a prohibition on the use of all engineered stone, irrespective of crystalline silica content.
SWA said engineered stone workers were “significantly over-represented in silicosis cases”.