Import taxes on future industries that locate near foreign trade zones across the nation — including 5,000 acres between Vicksburg and Jackson — will be higher if proposed regulations on the duty-free areas are allowed to stand, economic development officials said.

Foreign trade zones are areas where manufactured products may be stored, processed and moved without custom duties. New rules would force such designations to expire after three years if borders at zones such as the Port of Vicksburg or Ceres Research and Industrial Interplex at Flowers is expanded for new business.

“This could have an impact, because we’re getting a lot of inquiries from German, Belgian, Dutch companies,” said Wayne Mansfield, executive director of the Warren County Port Commission.

All decisions on expansion would be left to the executive secretary of the Foreign Trade Zones Board, part of the Department of Commerce, one of myriad changes effective April 30.

Other conditions, such as allowing the board to issue case-by-case waivers when trade zone areas seek consulting or legal advice, will be sent to the Office of Management and Budget for more review and an effective date remains to be announced.

Vicksburg and Warren County supported the port commission’s opposition to the new rules. The letters will be sent to U.S. Rep. Bennie Thompson’s office, Mansfield said.

The long-term net effect will be “one less option” on the table for business recruiters, said Craig Pool, president of the Mobile, Ala.-based Foreign Trade Zone Corp.

“It’s not just Mississippi,” Pool said. “If you have a three-year sunset, it will delay economic development and it may lose manufacturing jobs.”

The port and Ceres are two of 17 general-purpose sites in the Vicksburg-Jackson Foreign Trade Area, which takes in central and north Mississippi. Thirteen sites are in the Mississippi Coast Foreign Trade Zone Areas, including the John C. Stennis Space Center and the Port of Pascagoula. Individual businesses with subzone status in the state include the Nissan plant in Canton and Huntington Ingalls shipyard in Pascagoula.

More than 230 foreign trade zone projects and nearly 400 subzones are in effect in the U.S.