Four men went on trial in the northern Spanish city of La Coruna Tuesday, including the tanker's Greek captain.

More than 200 witnesses and experts are expected to testify during the proceedings, which are set to last into May, 2013.

Captain Apostolos Mangouras, now 78, is joined by Greek chief engineer Nikalaos Argyropoulos and first mate Irineo Maloto of the Philippines. They are charged with harming the environment, and prosecutors are seeking 12 years of jail time. Maloto, who fled the country, is being tried in absentia.

The fourth defendant is Jose Luis Lopez-Sors, who was head of the Spanish merchant navy at the time. The accused are not expected to take the stand until November.

Worst oil spill in Spanish history

Greek-operated and Bahaman-flagged, the Prestige took on water in a storm on November 13, 2002, and began leaking. Then prime-minister Jose Maria Aznar ordered the tanker to be towed away from the Spanish coast instead of following an expert-prepared contingency plan that called for the ship to be brought closer to shore where the spill could be confined.

The Prestige eventually broke up and sank on six days after the incident began, leaking 77,000 metric tons of fuel in total into the Atlantic, polluting thousands of miles of coastline in Spain, Portugal and France.

A report released in 2010 revealed that fisherman who helped with the cleanup effort suffered genetic and lung problems.

Government officials not held accountable

Environmental groups have argued that high level officials, who should share blame in the disaster, are not being held accountable.

"There are many people who should be in the dock as well who are not there," said Maria Jose Caballero, coordinator of Greenpeace Spain campaigns. She added that Spanish Prime Minister Mariano Rajoy, who was deputy prime minister and government spokesman at the time of the incident, should also be held accountable.

"We feel that the government's management of the accident bordered on negligence," Caballero said.

Rajoy initially downplayed the significance of the incident, calling the black spots that appeared in the sea where the Prestige went down "small threads of clay."

Environmentalists in Action, a Spanish non-government group, said charges should be brought against ABS, the marine classification company which certified the aging tanker as seaworthy, complaining that single-hull tankers are still being used to transport fuel.

Outside the court around 300 people gathered to protest the government's actions in dealing with the spill.

During the first day of proceedings the court is expected to evaluate the total cost of the damage - thought to be over 2 billion euros ($2.6 billion) and sought by more than 2,000 plaintiffs. A verdict is expected in September 2013.

dr/rc (AFP, dpa)