President Biden on Monday called on Congress to pass legislation to avert a rail shutdown before Dec. 9, warning of major disruptions to the U.S. economy if lawmakers don’t act.

He said Congress should pass a bill “immediately to adopt the Tentative Agreement between railroad workers and operators — without any modifications or delay — to avert a potentially crippling national rail shutdown.”

Biden’s plea to Congress comes amid an ongoing labor standoff that could shut down crucial shipments of food and fuel.

The tentative Biden-backed agreement in September was approved by labor and management negotiators, but not every rail union has signed on.

Biden said that Labor Secretary Marty Walsh, Agriculture Secretary Tom Vilsack and Transportation Secretary Pete Buttigieg have been in regular touch with labor leaders and management since then but see no path to resolve the dispute at the bargaining table.

The secretaries have since recommended that the administration seek congressional action to solve the issue. Biden said that while he is a “proud pro-labor President” and “reluctant to override the ratification procedures,” Congress has to work to adopt the deal.

“On the day that it was announced, labor leaders, business leaders, and elected officials all hailed it as a fair resolution of the dispute between the hard-working men and women of the rail freight unions and the companies in that industry,” he said.

Biden, in his statement, warned about the outcome if there is a shutdown.

“Let me be clear: a rail shutdown would devastate our economy. Without freight rail, many U.S. industries would shut down,” he said, adding that union workers would be out of work, communities would struggle to get chemicals that ensure clean drinking water and farmers and ranchers would be unable to feed their livestock.

The tentative deal reached in September would give union members a 14 percent raise, and workers whose pay had been frozen would get a higher wage increase and a boost in medical care. The Biden administration was largely credited at the time by both sides for stepping in to avert a strike.

The president said that the agreement was reached in good faith by labor and management and warned against changes. He said he shares the workers’ concerns about the agreement not including time to recover from illness or care for a family member, but that he is working to advance paid leave.

“Some in Congress want to modify the deal to either improve it for labor or for management. However well-intentioned, any changes would risk delay and a debilitating shutdown,” he said.

“But at this critical moment for our economy, in the holiday season, we cannot let our strongly held conviction for better outcomes for workers deny workers the benefits of the bargain they reached, and hurl this nation into a devastating rail freight shutdown,” he added.