Surat: Four workers, including a supervisor, died after allegedly inhaling toxic gas while cleaning an underground Effluent Treatment Plant (ETP) tank at a jewellery processing unit in Surat’s Khand Bazar area on Saturday.

The incident occurred at Rati House (Ratih Jewellers), located near the Choryasi Dairy premises. According to fire officials, the workers had entered the underground tank chamber for routine cleaning when they became unconscious and got trapped inside.

A Fire Brigade team rushed to the spot after receiving an emergency call at around 10:22 am and launched a rescue operation. All four workers were pulled out and rushed to SMIMER Hospital, where doctors declared them dead.

The deceased were identified as Nimesh Vitthalbhai Savaliya (26), supervisor; Vikas Kumar Santoshbhai Sonawane (24); Vijay Bhikhabhai Ahire (24); and Yogesh Nanabhai Jadav.

Varachha Zone ‘A’ Divisional Fire Officer Ranjitsinh Khadiya said the initial information suggested that one person had fallen into a chamber. However, upon reaching the site, rescue teams found four workers inside the ETP tank. He added that no personal protective equipment (PPE) was found either on the workers or at the site, indicating possible negligence, though the exact cause will be determined after a detailed investigation.

Deputy Commissioner of Police Alok Kumar said the tank was used to collect waste generated during jewellery processing and was cleaned periodically. Preliminary findings suggest the workers may have lost consciousness due to suffocation or toxic gas exposure after entering the tank.

Police have registered a case of accidental death and launched an investigation. CCTV footage from the factory premises is being examined to determine the sequence of events. Officials said strict legal action would be taken if negligence on the part of the factory management is established.

An ETP (Effluent Treatment Plant) is a system used to treat industrial wastewater by removing harmful chemicals and contaminants before the water is discharged or reused.