SIX workers drowned after falling into a giant vat of sauce at a tomato sauce factory in India, the Indian Express reported.

The horrifying incident unfolded Wednesday evening when a female worker slipped and fell into the 6m deep tank.

As five colleagues dived in to grab her they were all overcome by fumes given off from fermenting vegetables and drowned, the newspaper said.

Two more workers were in a hospital following the tragic incident at the Akansha Food Products unit in Lucknow, in the Uttar Pradesh region of northeastern India.

Investigators say the woman, named as Usha, was scooping up fermented vegetables from the vat when she slipped off her ladder and plunged into the raw material used to make the sauce.

“When the woman fell in, the other workers jumped in to help her,” said Rajiv Krishna, Lucknow's Senior Superintendent of Police.

The factory owner was taken into custody, the Indian Express said.

Originally published as Six workers drown in vat of tomato sauce