Questions about the earthiest of matters — whether there is such a thing as clean dirt and, if so, does it exist in Chicago? — are at the heart of a bitter policy fight between two powerful, politically connected industries: landfill and quarry operators.

Next week in Springfield, the Illinois Pollution Control Board will begin what promises to be a highly charged set of hearings about rules proposed by the state Environmental Protection Agency to define whether dirt and debris from construction and demolition sites is clean enough to be deposited in quarries. Such dirt and debris has long been deposited there, and state statutes mandate that the deposits be clean. But “clean” has never been clearly defined.

The debate over the proposed regulations is expected to resonate in suburban communities that get their water from aquifers connected directly to quarries, which have no linings or barriers to prevent toxic materials from leaching into the water supply.

It has pitted quarry operators, who say that the proposed regulations are too strict and costly, against landfill operators, who say the proposed rules are too lenient and will lead to polluted drinking water.

The landfill operators say most dirt in Chicago is contaminated enough that it should be going to landfills, which have waterproof liners and stricter monitoring requirements.

In 2010, the State Legislature passed a law that requires the pollution control board to develop rules to ensure that contaminated dirt is not dumped in quarries.

“How do you define uncontaminated?” asked Matthew Dunn, chief of environmental enforcement for the Illinois attorney general.” One side says well if it’s not too contaminated, if it’s just normal urban contamination, we can still call it ‘clean,’ while the other side says if it contains chemicals or metals that didn’t come from God or the glaciers it is contaminated.”

Quarries are usually owned by construction companies, which mine them for gravel, sand and other materials for building roads and making concrete. After the companies stop mining, they can earn income by accepting “clean construction and demolition debris” for a fee. Such material includes concrete, bricks and other rubble often mixed with dirt that can contain toxic metals and chemicals.

Under the proposed rules, dirt headed for quarries would have to be tested for specific contaminants and could not be dumped if it exceeded limits for what was considered safe. Quarries would also have to monitor nearby groundwater once a year and report any problems to the state within 60 days.

Pressure for regulation has increased amid concerns that some quarries were accepting dangerously contaminated dirt. A Joliet quarry was fined $20,000 last year after the Illinois attorney general, Lisa Madigan, accused it of accepting contaminated materials.

Both the quarry and landfill industries are known for their political clout. A leading player in the quarry business is Michael Vondra, a major donor to city and suburban politicians whose construction companies have received millions of dollars in city contracts. The landfill company Waste Management has spent generously for decades on campaign donations and has won contracts for hauling Chicago waste.

State legislation to regulate construction dirt in quarries was proposed in 2009 but died after an outcry that it was too lenient. Revised legislation passed in the summer of 2010, mandating that the pollution control board issue new rules by July 2012.

“It is good to see that the rule-making process is progressing to eliminate ambiguity and raise the bar by establishing more stringent requirements, standards and controls,” said Joshua Robbins, a spokesman for Vulcan Materials, which owns several Chicago-area quarries.

In comments filed with the state environmental agency, the attorney general said that protective barriers should be required for quarries accepting construction debris. The proposal does not include them. Madigan also said the rules should require groundwater monitoring at least twice a year instead of once a year, as the agency recommended.

According to James Morphew, a Springfield lawyer for the National Solid Waste Management Association, a landfill group, “The big problem we see is with groundwater monitoring and protection.”

“It’s not as simple as we’re going to lose business,” Morphew said. “It is a legitimate concern if material with this level of contamination is going to holes in the ground without liners.”

Under the proposed rules, construction and demolition managers would in many cases need to pay professional engineers or geologists to certify that their dirt was clean. Quarry operators would also have to test the dirt with an electronic meter and pay for the annual groundwater monitoring.

Greg Wilcox, executive director of Land Reclamation and Recycling Association, a quarry owner group, called the proposed screening requirements redundant, comparing them to wearing “a belt and suspenders.”

If dirt is deemed too contaminated for quarries under the new rules it would have to go to landfills, where it costs more to deposit waste. The City of Chicago could see costs increase under the proposed rules, since many city agencies, including the Chicago Public Schools, do much building and demolition.

The state environmental agency and some experts say that low levels of chemicals and metals are safe and should not preclude dumping dirt in quarries.

“In the city of Chicago, if you take a sample of dirt and look hard enough, you will find chemicals in it,” said John Hock, an environmental consultant to quarries.

Jack Darin, director of the Illinois Sierra Club, opposes dumping dirt in quarries but thinks the proposed rules are an improvement from the current, largely unregulated situation. “Quarries are usually about the last place you would want to put waste material, because usually a primary goal of any waste facility is to keep waste out of contact with the water table,” Darin said.

The new rules would rely on companies to monitor themselves and report problems, with little direct oversight by the Illinois Environmental Protection Agency. The agency’s land pollution division director, Doug Clay, said self-monitoring was reinforced by state regulators who periodically inspect quarries, and he was not aware of any past incidents of groundwater contaminated from construction dirt.

Jim Moustis is the board chairman for Will County, home to the Joliet quarry fined for contamination as well as at least nine other quarries permitted to accept construction dirt. He thinks the proposed rules legitimize a practice that he fears will taint drinking water.

“To not require some type of lining defies common sense,” Moustis said. “You don’t have to be a geologist or chemist to know no good can come of that.”

Idalmy Carrera contributed reporting.