TULSA, OKLA. ? Notice of plans to sell mining waste piled on Indian allotment lands during decades of lead-and-zinc mining in northeastern Oklahoma went out to construction companies in three states on Friday.

The Bureau of Indian Affairs sent the notice to companies in Kansas, Missouri and Oklahoma that might be interested in buying some of the estimated 40 million tons of chat on land owned by members of the Quapaw Tribe. The bureau plans to offer 16 chat piles for sale with the goal of holding a pre-bid conference by the end of July.

Chat forms gray mountains within the Tar Creek Superfund site in the northeastern corner of the state. Sales of the chat from Indian allotments had been put under a moratorium by the BIA in October 1997. Agency officials, who control use of the land as trustees, set the moratorium because of concerns about potential liability.

Disturbing the lead-laden piles has previously raised red flags for federal and state environmental agencies. The current plan to sell the chat for use in road construction, however, addressed those concerns, said Judy Duncan of the Oklahoma Department of Environmental Quality.

“It’s fine with us,” Duncan said. “The DEQ and the University of Oklahoma studies of chat in asphalt have shown that the lead in the chat appears to stay encapsulate in the asphalt, even when that asphalt is ground.”

The plans to sell the chat represented the first step under a February agreement between the U.S. Environmental Protection Agency and the Department of Interior. The agreement settled procedures for selling the chat and steps necessary to prevent additional damage to the Tar Creek area.

Chat, a waste product of the mining that went on in the area from the early 1900s until 1970, is spread throughout the 44-square-mile district in northern Ottawa County. The chat in piles ranges from fines that lack commercial value up to larger gravel and even boulders left from the former mining activity.

Acid drainage from closed mines led to the Tar Creek area’s addition to the Superfund list in 1983. The piles of waste, lead in the ground, water problems and children’s elevated blood lead levels have been parts of the continuing environmental problems in the area.

Federal agencies, primarily the EPA, have spent more than $100 million attempting to clean up the area. Almost all the chat removed during that time came from privately owned piles.

Cynthia Fanning, a spokeswoman for the EPA regional office, said a pilot project with the Interior Department to facilitate chat sales fit within plans to continue work in the area.

“The DOI has worked with the EPA to develop a sales agreement for third parties and a model site operations plan,” Fanning said. Those plans fit within chat handling guidelines released by the EPA in 2002, she said.

The February agreement addressed procedures and provided guidelines for the removal of chat. The agreement, which federal officials said also should limit liability, included measures for sorting the chat, retaining water run off and keeping dust down. It also included safety measures to protect workers.