The S.C. Transportation Infrastructure Bank effectively took out a payday loan for highway construction when it approved additional money for the completion of the Mark Clark Expressway, said Coastal Conservation League leader Dana Beach.

Beach, who is opposed to the extention of Interstate 526, was one of several speakers at a South Carolina Policy Council press conference Wednesday in Charleston.

The conference was unusual for the conservative group in that members of the tea party, an environmentalist and a local civil rights leader all spoke at the event.

Policy Council President Ashley Landess said the conference was held to present a united front in opposition to corruption in state government. She defined corruption as “a concentration of power and secrecy,” and said actions don’t need to be illegal to be corrupt.

Beach said funding for I-526 was a great example of corruption. The seven-member bank board already had approved $420 million for the project, which has not been ranked a state priority.

Then at a meeting this month it approved an additional $138 million for the project, which many local residents have said they don’t want. When the board did that, Beach said, it committed money it would borrow after 2020, because it has no bonding capacity left now.

Money for I-526 will take all the bank’s current resources and “a substantial amount of the resources of the next generation,” Beach said.

He also said that money from the Infrastructure Bank mostly has gone to projects in counties in which bank board members or those who appointed them live. “It’s indisputable that the state Transportation Infrastructure Bank is a slush fund,” he said.

For instance, he said, Charleston County has received more than $1 billion of the $4 billion the bank has allocated since 1997. Two of the seven bank board members live there, and four of the six elected officials who appoint them also live in Charleston County.

House Speaker Bobby Harrell, a Charleston Republican and staunch supporter of I-526, appoints two members of the bank board. He has said the road is needed to alleviate traffic woes and for safety. He has worked diligently in recent months to bring in money for it.

He said he thinks arguments made at the press conference opposing funding for I-526 are not true.

“The Infrastructure Bank has delivered major projects for communities all over our state, from the Lowcountry to the Upstate and across the Midlands to the Pee Dee,” he said. “This is just the desperate actions by a few who, unlike the vast majority of Lowcountry residents, want to stop the completion of 526.

“They have proven there is no depth too low or tactic too underhanded for them in their effort to kill the completion of 526.”

Harrell vowed to continue to fight to complete the interstate loop around Charleston.

Landess said I-526 was an example of a corrupt system where a handful of politicians control the Legislature, the judicial branch and most state agencies. What the state needs is across-the-board reform, she said.

In South Carolina, she said, “citizens are victimized by politicians who have forgotten for whom they work.”

Reach Diane Knich at 937-5491 or on Twitter @dianeknich.