Calcutta, Dec. 7 :    Calcutta, Dec. 7:  The government has closed down Frigerio Conserva Allana Limited, a meat processing factory in Mourigram, Howrah, two days after terrified residents stormed the plant following leakage of ammonia gas. Environment minister Manab Mukherjee said a team of officials from the Pollution Control Board and the inspector of factories conducted a probe into the leak and recommended steps to avoid future toxic emissions. 'We have asked the factory authorities to keep the plant closed till they implement the recommendations,'' he said. Mukherjee added that the refrigeration unit of the factory has not been closed down as 300 tonnes of buffalo meat is still under process. 'There will be a major pollution and health hazard if such a huge quantity of raw meat rots,'' he said. S.J. Padrikar, general manager of the unit, however claimed that the factory had already implemented the measures recommended by the environment minister ever since they started trial production. According to local residents, a similar incident of toxic emission occurred on October 28. Of the four factory workers injured, one died at the West Bank hospital where he was being treated. Another worker lost his right eye. 'We have promised to look after the family of our deceased staff,' Padrikar said. The residents today observed a 12-hour bandh in the area. They also squatted on railway tracks, disrupting rail traffic for over an hour. The Mourigram Paribesh Suraksha Committee, a forum floated by the residents in protest against the 'illegal factory', took out a procession and demonstrated in front of the factory gates. Mukherjee said the preliminary enquiry report reveals that ammonia condensate in the vapour line was misjudged and that the isolation valves might have malfunctioned. The report also did not rule out failure of the refrigeration system. At a press conference in Writers' Buildings today, the minister said the leakage was an accident. The recommendations suggested are installation of an ammonia detection and monitoring system and a self-contained compressed air breather.