A bill that would free the state Department of Transportation from paying hundreds of thousands of dollars in fines for polluting Georgia’s waterways has moved out of subcommittee, despite push-back from several quarters.

The DOT racked up more than $2 million in fines in the past decade — including $450,000 in fines for 20 sites with water pollution in 2008 alone — when soil ended up in waterways during road-building and other projects.

The DOT is the state’s largest polluter, and dirt is the biggest problem with water pollution, because mud can literally choke the life out of water.

Transportation Chairman Jay Roberts, speaking in subcommittee on Tuesday, described advancing House Bill 131 and exempting the DOT from those fines to the Environmental Protection Division as a constitutional imperative.

“Currently, we’re taking motor fuel dollars and paying fines with them,” Roberts said. “In my mind, that’s a direct violation of the state constitution.”

That question did not go to a committee attorney. Instead, environmental groups argued that the change will make environmental regulations ineffective, and private highway contractors said they are nervous that they could be alone in paying fines if problems occur.

“We need some way for both of us to be on the hook, because we are both party to the permit process,” said David Moellering, head of the Georgia Highway Contractors Association. “Remember, we’re implementing the plans the state put into design.”

Lawmakers tried to address the contractors’ concern by having the current soil and erosion panel act as an arbitrator in disputes.

Private contractors also would get 30 days to make fixes under an amendment to the proposal.

Even with the changes, though, the bill may face an uphill climb. Some House leaders have questioned giving a state agency a break that isn’t available for businesses or individuals in the same industry.

There also is concern that without a state agency to enforce the federal Clean Water Act, a federal agency such as the Environmental Protection Agency will step in.

Any fines then would go to the federal agency, which often levies $900,000 to $1.5 million penalties in a single violation, said Jason Ulseth, the technical program director at the Upper Chattahoochee Riverkeeper.

“We’re not eliminating fines. We’re just changing where the fines go to,” Ulseth said. “If you want to get rid of the fines, maintain compliance.”

The proposal next heads to the Transportation Committee for a full review. It has not yet been put on the calendar.