Calcutta, Aug. 25 :     The state government is issuing a notification to clear all closed factories of hazardous chemicals in the wake of the Lake Town incident, where an abandoned unit has been discharging toxins into the environment. A senior environment department official said today that the board would also make a list of closed factories which were a potential threat, especially to residential areas. The notification will ensure that all units clear their factories of harmful chemicals before they decide to close down or suspend production. In the meantime, the state environment department has written to the ministry of environment and forests for a grant of Rs 5 lakh to facilitate the removal and disposal of the harmful chemical from the Lake Town factory. The ministry had made a similar grant to tackle the Dasnagar chemicals godown fire, which resulted in the death of four persons last year. Residents of Lake Town continue to suffer as poisonous benzyl chloride leaked into a pond in the area. Yesterday, BJP activists tried to pump out the water of the pond but were prevented by the district administration. The authorities have begun moving in drums to carry the chemicals out. But the exact nature of chemicals stored in tanks above and below ground level was yet to be determined. There has been no breakthrough in locating the owners of the factory. Environment department officials said clearing the factory would take some time. ?We have set up a panel of experts, including professors from Jadavpur University, to advise us on the matter,?? officials added. The operation is being overseen by the district crisis management group headed by the district magistrate.