Commodities groups are sounding the alarm as a potential railway strike threatens to cripple transportation of vital goods from food and lumber to coal.

Freight railroads and labor unions worked through the weekend to try to avoid a strike that could cost the U.S. economy more than $2 billion a day, though there isn’t much sign of progress ahead of a potential Sept. 17 walkout. A strike would threaten shipments of grains, fertilizer and energy when global food prices are elevated and inflation ripples through economies.

The threat comes as the world increasingly turns to the U.S. for food supplies, with Russia’s war in Ukraine roiling commodity markets and disrupting grain shipments from the Black Sea, one of the world’s breadbaskets. The U.S. coal industry also faces significant impacts since the vast majority of the power-plant fuel is transported by train.