Indium damages LCD plant workers' lungs

NEW YORK (Reuters Health) - Japanese researchers have found emphysema-like changes in the lungs of workers exposed to indium, a material used in the production of liquid-crystal displays (LCDs) and plasma display panels.

"Inhaled indium could be a potential cause of occupational lung disease," Dr T. Chonan of Nikko Memorial Hospital in Hitachi and colleagues conclude.

Manufacture of liquid-crystal panels has been increasing over the past 10 years, meaning more and more workers are being exposed to indium, Chonan's team notes in the European Respiratory Journal.

Animal studies have shown that indium compounds can cause lung inflammation and cancer when inhaled, and there have been two cases of serious lung injury in workers at an indium processing plant, one fatal, they add.

To investigate the effects of indium exposure, the researchers performed high-resolution CT scans of the lungs of 108 men working at the same plant where the injuries had occurred.

Twenty-three of the workers had significant interstitial lung changes, meaning their lung tissue showed scarring and inflammation. Forty had abnormally high blood levels of an antigen called KL-6, a marker for interstitial lung disease.

Workers with the highest levels of indium in their blood had been exposed to the material for the longest time, and also showed more severe changes in their lungs on CT scans and higher KL-6 levels

Recent efforts have been made to increase safety in indium processing plants -- for example, requiring workers to use dust respirators, the investigators note. However, they add, evidence suggests that indium causes lung changes that persist even after exposure ends.

The researchers call for "careful follow-up" of indium-exposed workers as well as efforts to eliminate indium exposure.

SOURCE: European Respiratory Journal, February 2007.