The fishermen, who were among a group that ventured into the sea from Kodiakarai in Nagapattinam on March 1, spotted the container off the coast on Saturday, opened it and found the liquid inside. Mistaking it for alcohol, they reportedly consumed it. All three fainted a little while later.
Other fishermen in the vessel, who did not consume the liquid, steered the boat towards the coast and reached the shore on Sunday morning, the sources said.
Antonysamy (38) from Thangachimadam near Rameswaram in Ramanathapuram district died on the way to shore. Another fisherman, Arockiya Prohit (50) was declared brought dead at the Nagapattinam General Hospital, while the third, a 26-year old man, succumbed while undergoing treatment on Sunday.
Officials of the Fisheries Department, Coastal Security Group police and other authorities are conducting investigations.