Test proves positive for the presence of formalin in fish samples. A cancer inducing chemical that is used illlegally to preserve fish has been found in as many as 11 out of 30 samples of fish species purchased from Chinthadripet and Kasimedu, the two major fish markets in Chennai, on two different days . Exclusively for The Hindu fishes were tested by the scientists of the Tamilnadu Dr. J.Jayalalitha Fisheries University. A low cost formalin detection kit was purchased on July 4th and July 8th and tests were also conducted on same day. Using the low cost formalin detection kit ,the presence of carcinogen, was scertained.Carcinogen is widely used as a preservative and disinfectant. Formalin causes irritation in the eyes, throat, skin and stomach. In the long run continued exposure causes harm to the kidneys, liver and can even cause cancers. This is the first time samples of fish in Tamil Nadu have tested positive for formalin. Food Safety and Standards Authority of India (FSSAI) officials have been undertaking tests at fish markets and harbours across the State to test for formalin following a scare in neighbouring Kerala that fish sourced from here were chemically contaminated. Fisheries Minister D. Jayakumar said use of formalin as a preservative cannot be allowed at any cost. He said tests had been conducted in Thoothukudi and other places based on information received by the department but none of those samples had any formalin.