An environmental group in Dalian, Liaoning province, is demanding 645 million yuan ($104 million) for damage it says resulted from pollution caused by the China National Petroleum Corp in July 2010.
The claim is the largest made in an environmental case in the country.
Dalian's Maritime Court said it attaches great importance to the case because it is the first of its kind, and it is currently reviewing the indictment.
On July 16, 2010, a crude oil pipeline in Dalian caught fire and exploded, causing more than 1,500 metric tons of oil to gush out and pollute 430 square kilometers of water. A 12-sq-km area was severely polluted.
A firefighter was killed and a worker was missing, and economic losses were estimated at 223 million yuan.
On Friday, the Dalian Environmental Protection Volunteer Association, a nonprofit organization founded in June 2003, filed the lawsuit against seven companies owned by the CNPC that are alleged to be responsible for the accident.
More than 20 vessels were deployed to spray chemicals to clear the oil, and a 7-km barrier was set up to contain the spill.
The city's maritime authority said 92 percent of the leaked oil was recovered by the end of July 2010.
Fourteen people were held by prosecutors and 29 employees of the CNPC have received penalties for contributing to the accident by violating Party or administrative rules. Jiang Jiemin, the company's then-president, received a warning.
Tang Zailin, the association's vice-president, said the organization had wanted to take action for some time, but the Environmental Law did not allow nonprofit groups to sue companies until an amendment was enacted on Jan 1.
"It will take years to clean the pollutants in the water," Tang said. "Our association took part in the cleanup operation. We used dispersants to split up the particles of oil so they fell to the bottom of the sea. The damage to the environment is likely to continue for the next 20 years."
Tang said the amount of compensation being sought was calculated after an evaluation by a team of environmental professionals and lawyers.
"We wish to send a warning to other companies through the lawsuit."
Since 2010, there have been six fires at oil refining facilities operated in Dalian by CNPC, the country's largest oil and natural gas producer and supplier.
