(CNN) -- A federal judge ruled Thursday that the Tennessee Valley Authority is liable for a coal ash spill in eastern Tennessee in which a massive mixture of toxic ash and water blanketed approximately 300 acres.
"... had TVA followed its own mandatory policies, procedures, and practices, the subsurface issues underlying the failure of North Dike would have been investigated, addressed, and potentially remedied before the catastrophic failure of December 22, 2008," U.S. District Judge Thomas A. Varlan wrote in his 130-page decision.
Plaintiffs have three weeks to file briefs recommending how the court should proceed in the next phase -- in which they must show they are entitled to relief.
In a statement, TVA said its "commitment has not wavered -- to clean up the spill, protect the public health and safety, restore the area, and, where justified, fairly compensate people who were directly impacted."
It added, "TVA remains committed to the full restoration of the community directly impacted by the spill, while being mindful of our responsibility to manage ratepayer dollars."
TVA said it has bought more than 180 properties, settled more than 200 other claims from area residents and gave $43 million to the Roane County Economic Development Foundation.
It predicted the recovery project will continue through 2015.
The spill began before dawn when the walls of a dam holding back more than 1 billion gallons of coal ash waste stored in a retention pond at TVA's Kingston Fossil Plant, 35 miles west of Knoxville, trembled and crumbled. The mixture of water and ash, enough to fill nearly 800 Olympic-sized swimming pools, fouled the adjacent Emory River.
There were no deaths, but three homes were destroyed and about a dozen others damaged.
The spill contained toxic materials such as arsenic, selenium, lead, chromium and barium. But the TVA and the federal Environmental Protection Agency have reported that air and drinking water in the area were safe and that the levels of toxic substances did not exceed federal standards.
Thursday's decision was followed closely by nearby residents. "I'm absolutely thrilled," said Sarah McCoin, who lives on the banks of the Emory River, about a mile from where the spill occurred. "It's just a huge accomplishment for our community and for other communities much like ours that are sitting in coal ash zones."
The ruling not only sets a precedent, she said, "it also allows people to hope that what happened to us will never happen to them."
McCoin, 56, said property values have sunk for the 40-acre farm that has been in her family for generations. "Would you spend your money to live here?" she asked. "No. Nobody would."
The possibility of long-term health effects remains a concern from the disaster, she said.
"It's infiltrated so much of our lives you start to become numb to it: The water's not good, don't swim in the river, don't eat the fish, if you fall overboard, hurry up and get back on your kayak."
In 2010, Tennessee state officials slapped the TVA with $11.5 million in fines after the state's Department of Environment and Conservation determined that the authority had violated state clean-water and solid waste disposal laws.
The TVA itself agreed to pay $40 million for economic development projects in Kingston in 2009 as part of a larger fund set up for cleanup efforts.