The deceased were identified as Lakshmanan (48), a wage worker from Valluvapakkam, and Sunil (26) of Muthiyalpettai. Police said Sunil tried to rescue Lakshmanan, but inhaled the gas and died on the spot.

According to the police, Lakshmanan went to the silk thread colouring factory in Muthiyapettai village to clean the septic tank along with Selvaraj (50) on Thursday afternoon. Lakshmanan entered the tank but became unconscious within a few minutes. Seeing this, Selvaraj, who was standing outside, raised an alarm and sought help. Hearing his cries, Sunil rushed to help Lakshmanan and entered the tank to rescue him. However, before he could do so, Sunil, too fell unconscious.

After being alerted by the local public, teams from Walajabad police and Kancheepuram Fire and Rescue Service rushed to the rescue them. However, by the time the officials managed to bring them out, both had died. Their bodies were send to Kancheepuram Government Hospital for post-mortem examination.

Sunil, staff of a private firm, was left unemployed during the shutdown and was searching for a job. The police have registered a case and are investigating.