Forty of the nation's largest business and trade associations are asking Congress to delay a Homeland Security Department cargo security mandate they say will have negative affects on commerce and security.

The groups, which include the National Association of Manufacturers and the Telecommunications Industry Association, are in a standoff with U.S. Customs and Border Protection over a coming regulation that would require them to submit 10 new categories of data on cargo containers before they are shipped to the United States by sea. The rule could be issued as soon as November.

In a letter sent Thursday to key lawmakers, the companies argued that the "10+2 rule" will cost U.S. companies more than $20 billion annually, which they say are costs that will likely be passed on to U.S. consumers. They want Congress to intervene and convince CBP to conduct a test program to study the matter.

"The proposed rule, which requires 10 new categories of data to be collected on U.S.-bound shipments 24 hours before loading in foreign ports, raises serious concerns for both large and small companies from every sector who depend on imported final products, parts and components for their U.S. operations," wrote the groups, which also include the U.S. Chamber of Commerce, Alliance of Automobile Manufacturers and the American Petroleum Institute. "Implementing the proposed rule, as presently drafted, will significantly raise the cost of doing business at a time when increasing global competition and a slowing domestic economy are creating new stresses on U.S.-based manufacturers and companies from every sector," they added.

Customs drafted the new regulation in response to a major port security law that Congress passed in 2006, when Republicans controlled both chambers. The law required the agency to get additional data on U.S.-bound sea cargo to improve its ability to identify high-risk containers.

Trade associations are not opposed to providing the government more information on their cargo, but want the new regulation to be feasible, said Catherine Robinson, a NAM associate director. More than 13 million cargo containers enter U.S. ports each year and 76 percent of all imports are manufactured goods, she added. She said the new regulation could require containers to sit at foreign ports for up to five days, which leaves them susceptible to tampering and could degrade or damage their contents.

"Our main concern with the rule is that it really has negative consequences for both national security and trade facilitation," she said. "What we've been saying is that trade at rest is freight at risk."

She said the groups are targeting their lobbying efforts on the House Homeland Security and Ways and Means committees. But they have made their concerns known to other congressional offices, as well as other federal agencies, such as the Treasury and Commerce departments.

"We believe that a prototype program conducted to the specifications of the proposed rule would be the best method for evaluating the proposed rule's impact on both security and business as well as for identifying ways to improve the rule before the government and industry invest billions of dollars in implementation," the groups wrote in their letter. Customs had no comment at presstime.