The U.S. Environmental Protection Agency (EPA) plans to propose new rules for some hard rock mines to ensure adequate clean up and at stopping mining companies from declaring bankruptcy to avoid pollution cleanups.

The Associated Press reported that the U.S. Court of Appeals for the District of Columbia Circuit ruled that the EPA must begin the rulemaking process for the hard-rock mining industry before the end of this year. The EPA agreed to take the actions listed in the order after it was sued in 2014 by six environmental groups.

At issue is a 35-year-old edict under the federal Superfund program that requires companies to show they have the financial resources to cover the costs of cleaning up ongoing contamination from their operations as well as any potential spills of hazardous materials. The lawsuits were brought to stop companies from claiming insolvency rather than paying cleanup costs, sheltering profits while leaving taxpayers to foot the bill.

The court said that companies will be more likely to invest in procedures to minimize pollution on the front end to avoid future liabilities if it is more difficult to walk away from polluted projects.

After writing the rules for mining companies, the EPA could go through a similar process for other industries, including chemical manufacturing, electric power generation, and petroleum and coal products manufacturing.

EPA spokeswoman Laura Allen said the agency is reviewing the court’s order.

The ruling comes five months after an EPA cleanup crew accidentally unleashed millions of gallons of contaminated wastewater at the idled Gold King gold mine in Colorado, turning rivers in three Western states a sickly shade of yellow. The Gold King Mine had shut down decades before, its owners leaving it behind to become filed with groundwater polluted by potentially harmful minerals.

Once EPA writes the new recommendations, the mining industry will have the opportunity to comment on them before they become final and then potentially challenge the rules in court.

Luke Popovich, spokesman for the National Mining Association, said the industry is disappointed in the ruling.

“Mining companies already have significant financial obligations already committed through state and federal mining reclamation and closure programs,” Popovich said. Those existing requirements address environmental risks at mine and mineral processing sites, he said, negating the need for a separate financial assurance program.”