The blood bank at R.G. Kar hospital has started using Hindustan Latex Limited-manufactured polybags after tests at the hospital's biochemistry laboratory confirmed the white sediment in the bags, detected after blood was stored in them last month, were "harmless," a senior technician at the bank said today. A report in The Telegraph on Friday said the state health department had curtailed the use of Hindustan Latex blood bags after complaints from R G Kar, Calcutta Medical College and the Central Blood Bank about the quality of the bags, 20,000 of which were supplied in early August.