Authorities in the southern Indian state of Karnataka state are investigating reports that raw silk adulterated with toxins has partially blinded at least 40 weavers.
Workers in Ramanagaram district have complained of eye injuries after handling cloth imported from China over the past three months.
Officials say a sample of the yarn has been sent for chemical analysis, the BBC reports.
Karnataka is a leading silk-producing state, but over the years, more Chinese silk has entered the market.
An official says chemicals have been added to increase the weight of silk and to make the cloth look more attractive - but there is no report of where or when chemicals might have been added.
Four weavers were admitted to a hospital in Ramanagaram last week after they touched a bag of raw silk. "Immediately, our eyes started to burn and our vision got blurred," said one of the victims.
There are more than 38,000 weavers in the silk-producing towns of Ramanagaram and Channapatna.