Port workers may strike if a labor agreement is not reached, threatening significant economic disruption with the potential impact on 35% of U.S. imports and exports.

With a potential strike at ports up and down the East Coast and along the Gulf Coast set to begin after midnight Monday, logistics executives tell CNBC the remaining hours are critical in moving out as much trade as possible before a shutdown that will do serious damage to the functioning of the U.S. economy.

A longshoremen’s strike will rekindle worries about shortages in stores and inflation weeks from a presidential election in which the economy has been a key issue.