Mumbai, Oct 7 (IANS): More than 20 hours after a fire broke out at a high speed diesel tank off the Mumbai coast following a lightning strike, a 50-member team of firemen continued to battle the blaze, an official said on Saturday.

The fire broke out on Friday on the tiny Butcher Island, which serves as an oil terminal for the Bharat Petroleum Corp Ltd (BPCL), around eight kilometres in the Arabian Sea off the landmark Gateway of India.

Clouds of smoke billowing in the sky were visible here and in mainland Raigad, two kilometres away.

"The situation is under control and there are no casualties. Efforts are on to control the fire by the Mumbai Port Trust fire personnel," BPCL Executive Director Manohar Rao told IANS, while en route to the island.

According to official sources, the affected tank capacity is around 40,000 tonnes, which was partly filled with HSD (High Speed Diesel). Nearly 25 per cent has been lost in the flames.

The fire brigade said the blaze was noticed around 5 p.m. after lightning struck the island and was initially battled by a team of safety officers stationed there.

Later, a team of Mumbai Port Trust, which has jurisdiction over the island, was sent by a speedboat to help battle the conflagration. The operation was on for nearly 20 hours.

The small island, also known as Jawahar Dweep, belongs to the Mumbai Port Trust and serves to offload crude oil from oil tankers which is stored in the containers there before being shipped to an oil refinery in Wadala.