Over 20 tonnes of thick oil powering oil tanker MT Dawn Kanchipuram has spilled into the Bay of Bengal, affecting the marine life and a long stretch of shoreline, the Indian Coast Guard said on Tuesday.
Efforts are on to clean up the oil, it added.
In a statement issued here, the Coast Guard said: "It is estimated that more than 20 tonnes of oil has spilt from MT Dawn Kanchipuram as against the initial report of two-three tonnes."
The collision between liquefied petroleum gas (LPG) vessel MT BW Maple and oil tanker MT Dawn Kanchipuram took place at 4 a.m. on Saturday off Kamarajar Port in Tamil Nadu, following which the oil spill happened.
The Coast Guard continued deployment of its ships and aircraft to coordinate the oil spill response from sea and in shoreline areas.
Post thorough assessment of the spill impact, the entire stretch between Ennore Beach to Elliot Beach (around 20 km distance) has been divided into four zones with dedicated teams for shoreline clean-up, the statement said.
The Coast Guard personnel are carrying out co-ordination and clean-up efforts with the assistance of personnel from the State Pollution Control Board and other non-government organisations (NGO).
High pressure super-sucker pumps have been pressed into operation to extract the sludge. The collected sludge is being transferred into bowsers. In addition, the inaccessible areas are being cleared manually.
The oil spill is disintegrating gradually due to wave action and weathering.
Seaward combating of oil slick is in progress by ICGS Varad. The ship has been deployed with spill spray arms and Oil Spill Dispersant (OSD).
The ship has dispersed about two tonnes of OSD to neutralise the slick at sea.
Approximately 95 per cent of the oil slick is towards the northern side of Chennai Harbour near R.K. Kuppam Beach.
It is observed that north of Chennai Harbour, about 11 locations over a shoreline stretch of 800 metres have been impacted with thick oil sludge, which has washed ashore, the Coast Guard said.
The cleaning of Marina Beach area, which is very minimally affected, commenced on Tuesday and is expected to be completed on Wednesday.
"The owners of MT Dawn Kanchipuram and M/s Dharya Shipping have been directed to hire private agencies for containment and recovery of remaining oil slick," it added.
The Coast Guard has asked the Principal Secretary and Chairman of State Pollution Control Board, Tamil Nadu, to nominate nodal officers for combating/recovery of oil spill in line with the State Oil Spill Disaster Contingency Plan.
The State Pollution Control Board has also been requested to activate the State Oil Spill Crisis Management Group, the Coast Guard said.