Update, Feb. 2—Clumps of oil that the Japanese Coast Guard believe are from the sunken Iranian oil tanker have begun washing up on the shores of Amami-Oshima in southern Japan, according to a report from Reuters.

The island is working to determine how widespread the oil is on its shores and to remove it quickly. Last month, the country's environment ministry said they didn't think the oil spill would reach Japan.

Jan. 25—An Iranian oil tanker that collided with a Hong Kong bulk freighter in the East China Sea is creating a new problem now that it has sunk—a possible environmental disaster.

When the oil tanker, the Sanchi, crashed on January 6, it spilled condensate into the waters about 160 nautical miles east of Shanghai, a high-traffic area for ships heading to and from China and other nearby countries. The New York Times reports the vessel burned for several days as rescuers tried to find missing crew members, then finally sank on January 14.

The oil tanker was carrying close to 150,000 tons of condensate, a light oil, when it crashed. It is unclear how much of the oil had burned off or spilled when it sank.

Because there are so many unknowns in this situation—the size of the spill, its chemical makeup, where the chemicals from the oil will spread—it is difficult to predict what impact this spill could have on the environment. The fires and gaseous fumes resulting from its leak almost certainly killed off marine mammals, fish, and birds within the immediate vicinity of the crash, Nature reports.

Unlike crude oil, which can create chronic environmental problems by sinking to the deep ocean and lingering there for years, hydrocarbon condensate is much lighter, evaporating or dissolving into water. That means short-term toxicity might be a bigger concern with this spill.