CHARLESTON — With Charleston’s crowded steamship terminals running out of space, the State Ports Authority has decided to start charging customers for steel shipping containers stored on port property more than a week.

Ports officials say some customers have been using terminals like a warehouse, moving containers to the port more than a month before they are supposed to be shipped.

Starting in June, the State Ports Authority will start charging the fees known as demurrage fees.

“If you think about arriving for your airplane two days early, you’re kind of in the way of people who are actually boarding,” said Fred Stribling, the authority’s vice president of marketing and sales. “It’s a national issue, and we’re right there with other ports taking it on.”

The authority isn’t expected to announce how much the fees will be until next week, but officials indicated they will be similar to those charged elsewhere.

Shipping companies including Maersk Sealand have told their customers such fees could be as high as $345 per day per container at some terminals.

State Ports Authority spokesman Byron Miller said that some loaded containers have been moved to Charleston terminals as much as five weeks before a ship is scheduled to sail.

“It’s an all-too-common practice,” he said.

“These companies will do large volumes of something, and once it’s produced, they want it out of their facility. The waterfront property we have is a very valuable resource, and we’re just trying to get the highest and best use of it,” he added.

The fee will be included in contracts negotiated between the authority and its customers. Many clients have already been told the fee will be imposed, Stribling said.