A conservancy worker died reportedly of asphyxiation and two others became unconscious while carrying out maintenance work in decommissioned submarine INS Vagli at the Chennai Port here.
Port sources said the three were employees of a private conservancy contractor and had entered the decommissioned submarine for maintenance work.
While one died, the two others were rescued, they said.
An enquiry into what caused the mishap is on, the sources added.
