Post updated 11:13 a.m. on Monday, 11/24/14.

After four years and a court order that pitted environmental groups against the coal industry, the Environmental Protection Agency is nearing its December deadline to finalize regulations for how coal-fired power plants dispose of the ash they create.

Coal ash — which contains toxic substances like mercury, lead and arsenic — can leach into groundwater if not properly contained. That has raised concerns among environmental groups who say Missouri does not properly regulate coal ash disposal.

Missouri is a coal-centric state; 83 percent of net electricity generated comes from coal. St. Louis-based energy companies include Ameren Missouri, Arch Coal, and Peabody Energy. Spokespersons for Ameren disputed that coal ash is toxic, and one estimated that complying with the new federal rule will cost the utility several hundred million dollars.

Power plants attempt to contain the coal ash in one of two ways: using specially designed ponds to hold the coal ash in liquid form, or compounding the ash into a solid and storing it in a landfill.

The Labadie Environmental Organization is currently opposing Ameren Missouri’s plan to build a coal ash landfill near the Labadie Plant. (read more here.)

According to the EPA, the rule will be the first federal regulation for coal ash. It has been in development since a 2008 spill in Kingston, TN, that displaced hundreds of people and contaminated millions of cubic yards of land and water. When the agency dragged its feet to publish a final rule, environmental groups sued. The EPA agreed to a December 19, 2014 deadline with a consent decree.

After meeting with federal officials regarding the coal ash rule, LEO president Patricia Schuba said she’s pressing the EPA for a strong federal rule that restricts coal ash disposal on flood plains. Until now, coal ash regulation has been left largely to state agencies, including the Missouri Department of Natural Resources. But the DNR does not regularly monitor groundwater near the existing coal ash ponds and landfills in the state.

Schuba pointed to data from other states, such as Illinois, that do require groundwater monitoring near the ponds and frequently detect levels of arsenic, lead and other contaminants nearby.

“Here in Missouri we hear that there are no problems. How do we know there are no problems? We have no data, no information. The public feels betrayed,” Schuba said.

A lobbying arm for the coal industry said that the heavy metals found in coal ash do not reach unsafe levels, and can be recycled in to building materials.

The most recent 10-Q Financial Report for Ameren mentioned the EPA’s plan to regulate coal ash impoundment. The report said it is still evaluating the cost of complying with the proposed regulations, which may require the utility to cap existing coal ash ponds and dispose of the ash in solid form. Ameren’s vice president of environmental services, Ajay Arora, said that when the ash is in solid form, it’s less likely to come into contact with groundwater or air.

“Even in advance of the rule, we are seeking to transition at Labadie to dry handling of ash in the future, which is an industry best practice,” Arora said.

Geochemist Bob Criss, a professor at Washington University-St. Louis, said regardless of how coal ash is stored, it should not be allowed to be in a floodplain.

“They’re perpetually wet. These are regions where it floods periodically, and they are regions where the groundwater table is very high. So, it’s practically impossible in the long run to keep water away from whatever garbage it is,” Criss said.

Ameren’s latest proposal for a coal ash landfill lies within a floodplain and the landfill may have "intermittent contact" with groundwater, the company acknowledged. (More about that issue in our previous coverage, here)

“There’s not a worse place that I can conceive of, as a geologist, to put any type of waste material than a floodplain,” Criss said.

To comply with a court order, the EPA is expected to release the finalized rule before December 19th.