The incident occurred at Ravi Frozen Foods located on the 28th Road of Wagle Industrial Estate, Thane. The company employs more than 300 contract workers for peeling, grading and packing of its marine products, which are then stored at a temperature of -40 degrees for export.

At 10.00 am on Wednesday, about 50 women were at work in the packing hall when one of the hose pipes carrying ammonia -- which is used to maintain the extremely low temperatures of the freezing unit -- gave way due to unregulated high pressure and the gas started leaking in the 2,000 sq ft airconditioned premises. All the women employees were affected immediately, and by the time an alarm was raised to shut supply of the gas, many of the women had already fainted and some were vomitting.

Thirty-seven of the employees were rushed tohospitals by the supervisors and other support staff of the company. While 17 of them were taken to the nearby Modi Hospital, 20 were taken to Thane Civil Hospital in a state of semi-consciousness.

Dr S M Dhog, medical officer of Thane Civil Hospital said: ``When the women were brought in, some of them were badly affected due to inhalation of ammonia. However, by evening, they were all responding to treatment and fast recovering.'' The women were kept under observation for 24 hours and discharged this morning.

On hearing of the incident, Wagle Estate police rushed to the spot and summoned the fire brigade personnel, who sprayed water in the packing hall to neutralise the gas. Assistant inspector D P Boraste said: ``It was a case of gross negligence by the maintenance staff, because of which the pressure of the gas shot up and the hose pipe burst.'' When contacted, company officials said: ``The leak could have become a major accident. Had it not been for timely intervention by the workers, more than 50lives could have been in danger.''

Police arrested Jayant Patki, director of Ravi Frozen Foods, Narendra Damania, engineer foreman and two others of the company under Sections 278, 284, and 336 for leakage of poisonous gas due to negligence and endangering the lives of employees. They have since been released on bail.