COLUMBIA, S.C. (AP) — South Carolina lawmakers are moving forward on proposals to shake up state laws and boards that enabled a costly nuclear fiasco, unanimously approving Tuesday six bills designed to limit how much more the state's power customers must pay for the now-defunct project.

The six proposals include one that would block project co-owner South Carolina Electric & Gas Co. from continuing to charge its customers $37 million a month for the scuttled project at the V.C. Summer Nuclear Station. Another bill could force SCE&G to refund the $1.7 billion that it already has charged customers.

Utility executives have warned against taking such measures, saying that cutting ratepayers' monthly bills could bankrupt the Cayce-based corporation. SCANA shares have dropped by roughly 25 percent since the project was called off in July, following the bankruptcy of lead contractor Westinghouse.

By the time the project fell apart, ratepayers had already footed $2 billion in payments toward the reactors. In introducing the bills last week, House Speaker Jay Lucas said they would "gut existing laws" that allowed such charges before the reactors were complete, like the 2007 Base Load Review Act. The new proposals would require that power plants be operational before utilities can charge their customers for that investment.

Lawmakers, state and federal authorities and Wall Street regulators are probing the failed project.

During a meeting Tuesday, House members bristled at concerns that some of the proposals would hurt state-owned utility Santee Cooper, the project's other co-owner. Lawmakers are also looking at ways to set new criteria for the utility's future directors, as well as require that Santee Cooper's rate-hike requests be regulated by the Public Service Commission.

Interim Santee Cooper chief executive Jim Brogdon said those moves would hurt the utility's credit rating, which could lead to higher interest rates for the utility and higher electricity costs for customers.

State Rep. Peter McCoy of Charleston, who chairs the panel, said legislators don't want to hurt Santee Cooper but can't be blamed for offering tough solutions to problems the utility helped create.

"This isn't something that I've done," McCoy said. "This is something that the (Santee Cooper) board has done, that agreements have done."

McCoy said he expects SCANA to file a lawsuit once the legislation is passed. At least half a dozen lawsuits are already pending, seeking to hold the utilities accountable for the failure.