The nation’s major container ports are expected to see another busy month in September ahead of a potential labor strike at East Coast and Gulf Coast ports, according to the Global Port Tracker report released by the National Retail Federation and Hackett Associates.

“This is a critical time as retailers prepare for the all-important holiday season, and we need every port in the country working at full capacity,” NRF Vice President for Supply Chain and Customs Policy Jonathan Gold said. “Many retailers have brought cargo in early and shifted to alternate ports as a precaution, but it is vital that labor and management at the East Coast and Gulf Coast ports actually sit down at the negotiating table and bargain in good faith for a new contract so we can avoid a disruption of any kind when their contract expires. A strike would be another blow to the supply chain as it continues to face challenges, and to the nation’s economy at a time when inflation is finally coming down and the Fed is poised to lower interest rates.”

The contract between the International Longshoremen’s Association and the United States Maritime Alliance covering East and Gulf Coast ports is set to expire on September 30. The ILA has continued to threaten to strike if a new contract is not reached by then. NRF last week renewed its call for both sides to come to an agreement before the contract expires, with NRF President and CEO Matthew Shay saying a disruption “would significantly impact retailers, consumers and the economy.”

“Import levels are being impacted by concerns about the potential East and Gulf Coast port strike,” Hackett Associates Founder Ben Hackett said. “This has caused some cargo owners to bring forward shipments, bumping up June-through-September imports. In addition, some importers are weighing the decision to bring forward some goods, particularly from China, that could be impacted by rising tariffs following the election.”