The Rena off in the distance. (Creative Commons)

At least 70 shipping containers dumped into the ocean early Wednesday and oil gushing at faster pace from a damaged ship piled up in clumps on the New Zealand coast, blackening the Bay of Plenty, closing beaches and killing birds, in the worst environmental disaster the nation has ever faced.

A massive Liberian cargo ship, Rena, became stranded last Wednesday after smashing into a well-known reef for reasons that remain unknown. The ship's captain was arrested early Wednesday and charged with operating a ship "in a manner causing unnecessary danger or risk." He will appear in court later in the day.

Stormy weather, dense fog and turbulent waves are dislodging more and more oil while preventing salvage crews from reaching the ship.

Officials said Tuesday in New Zealand that 53 birds have been found dead amid the spill and 17 were getting emergency treatment.

The ship had nearly 1,400 containers on board when it stalled, including 11 hazardous substance containers. Four of them contain a chemical that could cause an explosion if it touches water.

"It is highly likely that more will come off due to the current severe weather conditions and the vessel’s heavy list," the government said in a statement posted online Wednesday morning in New Zealand. "Once an aerial survey is completed, there will be a clearer picture of exactly how many containers have come adrift. This aerial survey will go ahead today once the weather has cleared and the sea conditions have improved."

About 1,870 tons of oil and 220 tons of diesel were likely on board before the leak began, meaning hundreds of tons of fuel could still spill.

According to the Associated Press:

The owners of the ship, Greece-based Costamare Inc., said they were "cooperating fully with local authorities" and were making every effort to "control and minimize the environmental consequences of this incident." The company did not offer any explanation for the grounding.

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