Houston-based oil and natural gas giant ConocoPhillips (NYSE: COP) has been fined $257 million to settle charges brought by the Chinese government following a massive oil spill. The company's Chinese venture partner, CNOOC Ltd., was fined $76 million.

The oil spill occured in June of last year, when some 700 barrels of oil and some 2,500 barrels of mineral oil-based drilling mud were released into Bohai Bay, off the country's northwest coast. The industrial accidents that led to the leaks occurred at two separate platforms, according to company statements. One platform has been repaired, while the other well is permanently plugged and abandoned.

The current fine is larger than analysts had expected, but comes amidst a case of environmental degradation that has cause widespread, and nationalist-tinged, outrage across the country.

ConocoPhillips said the settlement resolves all pending governmental claims regarding the spill. But the company might still face private claims. In January, a Chinese appeal court allowed local fishermen to file a $78 million class-action lawsuit against the company.

Shares of ConocoPhillips fell hard on the news, and closed the day down 21.08 percent, to $56.52 per share on the New York Stock Exchange, a 2012 low.