An organic compound was found to be responsible for the recent contamination of the Kelani River by the Coca-cola plant, National Water Supply and Drainage Board stated.

Quoting its Chairman Alahudeen Ansar, 'The Nation' newspaper reported that the test reports of water samples in Ambatale and other places have shown relatively high presence (0.5 mg per liter) of a methylene compound.

While the toxicity of methylene compounds can vary, it should never be mixed with drinking water, the Chairman also stated.

One methylene compound known to be associated with the manufacture of Cola compounds is 4-methylimidazole (4-MeI) which is contained in caramel coloring. In January 2011, California added 4-MeI to its list of probable carcinogens and stipulated 29 μg per day (29 micro grams per day) as the "No Significant Risk Level" intake. Studies have found levels of up to 700 micro grams per liter in cola soft drinks.