Four contract workers fell unconscious after allegedly inhaling toxic fumes while cleaning a wastewater tank at a private factory near Sriperumbudur in Kancheepuram district on Tuesday.

The incident took place at United Industries Plastic Private Limited, located at Vengadu village.

According to police, waste generated during the manufacturing process was stored in a wastewater tank situated nearly 40 feet below ground level inside the factory premises. The tank was reportedly cleaned once a year. The police said three contract workers entered the tank, and they allegedly inhaled toxic gas and began losing consciousness inside the tank. Hearing their cries, six co-workers rushed to rescue them.

Following the rescue operation, four workers — Manikandan, Madhanraj, Vignesh, and Sridhar — were affected due to toxic gas exposure. The workers were rushed to the Sriperumbudur Government Hospital. As the condition of two workers turned critical, they were later shifted to Shri Ramachandra Medical College Hospital in Porur.