A Dutch marine salvage company prepared on Tuesday to begin pumping half a million gallons of fuel from the stricken cruise ship Costa Concordia, the first step toward hauling the luxury liner away for a complete overhaul or cutting it up for scrap.

Workers from the company, Smit Salvage, expected to begin transferring the fuel, which weighs about 2,400 tons, to barges on Wednesday. About 200 tons of heavier oil will also have to be removed from the ship, which is on its side, half-submerged, off the Italian island of Giglio in the Mediterranean. The process is expected to take two to four weeks, depending on the weather.

The ship ran aground within a 30,000-square-mile zone that is designated a sanctuary for marine mammals, and Italian government officials and environmentalists are worried that rough seas may further damage the ship and cause a fuel leak. Company officials said that so far all of the ship’s 17 tanks are intact.

Mike Lacey, secretary general of the International Salvage Union, a trade group, said the salvage workers’ task would be a little easier because most of the fuel is diesel, which is relatively light and will not have to be warmed before pumping. “It’s not as bad as heavy fuel, but it can still make a mess,” he said.