Five members of Congress from Alabama have joined 20 of their colleagues in signing a bipartisan letter to the Biden Administration expressing “major concern” over what they say is an attempt to renegotiate provisions of a trade agreement.

Of particular importance to the Alabama delegation are how any changes might affect Vulcan Materials Corp. and its long-running dispute with the Mexican government.

U.S. Reps. Dale Strong, Barry Moore, Terri Sewell, Gary Palmer and Robert Aderholt signed the letter, dated Jan. 9.

The letter was sparked by reports that the U.S. Trade Representative is attempting to negotiate new provisions of the U.S. -Mexico- Canada Agreement and the U.S.-Columbia Trade Promotion Agreement. According to opponents of the move, the action would strip some investor protections from the agreement.

Palmer has called for a briefing to hear why the administration has taken this action.

The members of Congress, in their letter, are arguing that the Biden Administration should let any disputes be handled during the incoming Trump Administration, scheduled to take office Jan. 20. They believe any renegotiations might jeopardize ongoing disputes between U.S.-based companies and the nations.

The letter also complains that Congress and affected businesses were not adequately consulted.

This dispute is of particular interest with Birmingham-based Vulcan Materials, which is currently in active arbitration with the Mexican government.

Vulcan Materials has owned and operated a limestone quarry in Mexico for more than 35 years. The Mexican government in 2018 prohibited Vulcan from operating on two of its three parcels of land. Vulcan began arbitration proceedings to recover damages.

In May 2022, the Mexican government forcibly shut down Vulcan’s operations in Mexico. About a year later, Mexican military police breached Vulcan’s port facility at gunpoint.

Former Mexican President Andrés Manuel López Obrador threatened to declare the property a natural protected area or seize it by force if Vulcan didn’t accept a $360 million offer for the gravel pits.

Vulcan maintains the Punta Venado deep-water port facility has an estimated value of more than $1 billion.