Addressing a press conference, V V R Narsimham, Executive Director of the HPCL refinery, said the bodies of two workers were extricated from the debris, while 36 injured persons were being treat in various hospitals in the city.
Four to five workers are still reported to be missing, said another official of the government-run company.
Rescue operation was underway at the sprawling complex, where a massive blaze broke out last evening when workers hired by private companies were at work, Narsimham said.
Two workers died yesterday, while as many succumbed to burn injures at a corporate hospital in the port city early this morning. A thick layer of smoke engulfed the area causing panic among residents.
According to Narsimham, preliminary reports indicated a gas leak in the sea cooling water system caused the blaze.
He said three private companies were working on the wooden cooling tower which was completely gutted, and pegged the loss at Rs 15 crore.
HPCL Director (Refineries) B K Namdeo, who flew here from Mumbai, told the media that more than 100 workers were at the site at the time of incident. Four to five workers are reportedly missing. "We are planning to shift 3-4 critically injured to Mumbai or Hyderabad for better treatment."
As a precautionary measure, two production units have been closed and output at the refinery has been reduced to 60 per cent, the HR Director said.
The refinery has a current capacity of 8.5 million metric tones per annum (mmtpa).
He said an internal inquiry will be conducted by Hirak Datta, Executive Director (Oil Industry Safety) of the Navratna PSU who has already reached Visakhapatnam.
Union Minister of State for Petroleum Panabaka Lakshmi and the state's Tribal Welfare Minister P Balaraju visited the accident site and also hospitals, where the injured were admitted.
Union Petroleum and Natural Gas Minister Veerappa Moily is also expected to visit the refinery to assess the situation.