A drought has hit the Panama Canal, forcing some limits on the size of vessels that can pass through. This could have a sizable impact on U.S. agricultural shipments to Asia.

Almost 8 percent of grain vessels leaving U.S. Gulf export elevators could be impacted, according to an analysis of U.S. Department of Agriculture data back to January 2018.

There are some restrictions on movements of vessels with a draft larger than 13.1 meters (43 feet) effective May 28, the Panama Canal Authority said in an advisory notice dated May 3. The canal authority didn’t immediately respond to emailed requests for comment.