Angry at being left out of a compensation deal, about 500 fishermen from Shandong Province sued energy giant ConocoPhillips in the US for losses resulting from oil spills in the Bohai Bay area last year.

Three law firms in the US representing the fishermen filed the suit in the District Court in Houston on Monday, where the company headquarters are based, according to Jia Fangyi, a Beijing-based lawyer who helped build the case.

A total of 500 fishermen have signed contracts with the law firms and more are joining the suit. The final amount of the compensation claim has yet to be decided, but they are claiming about 870 million yuan ($137 million) in direct losses, Jia told the Global Times.

The company has not been served this lawsuit yet, John McLemore, a spokesman for ConocoPhillips, told the Global Times via email on Tuesday.

Tom Bilek, one of the lawyers, said that ConocoPhillips assumed responsibility and "we are trying to make them responsible," the AP reported.

Two oil spills occurred on June 4 and 17 last year at an oil field jointly managed by ConocoPhillips China (COPC) and China National Offshore Oil Corp (CNOOC) on Northeast China's Bohai Bay.

About 723 barrels of oil were spilled, polluting about 6,200 square kilometers of water. The damage was evaluated at around 1.7 billion yuan.

Official investigations concluded that COPC was at fault for the spills and should be held fully responsible.

At the same time, the Ministry of Agriculture has led negotiations between COPC, CNOOC and the local governments of Hebei and Liaoning provinces, both bordering the Bohai Bay.

According to a settlement they reached, COPC would pay 1 billion yuan for damages to the fishery resources while COPC and CNOOC would each pay 100 million and 250 million yuan respectively for fishery restoration and maintenance.

The deal failed to appease a large number of fishermen and lawyers.

"The authorities should sample the entire Bohai Bay area to assess the damage at different locations," said Jia. "Also the settlement is more like charity, rather than taking responsibility in proportion to the damage they caused."

Fishermen in Shandong have more reason to be angry as they have been completely left out of the deal.

"That's what's most aggravating, that they wouldn't admit they've caused damages to us," said Qu Baozheng, a fisherman in Muping county, Shandong.

The area lies to the east of where Bohai Bay meets the Yellow Sea.

Qu said about 70 to 80 percent of the scallops he raised in the Bohai Bay had died since the oil spills.

"The oil spills caused this, what else could it have come from?" he said. "Since we can't sue them in China, we will do this in the US."

Fishermen in Laoting, Hebei are also considering joining the overseas lawsuit as their case has yet to be tried six months after they filed a suit in Tianjin, said Jia.

Guo Kai contributed to this story