Several terminals at the ports of Los Angeles and Long Beach remained closed on September 27, after a tractor-trailer overturned on a vital artery for cargo, and sparked a fire among its payload of lithium batteries that may burn for a second day.

“The batteries have been damaged, and are on fire and off-gassing, with reports of one battery exploding,” the LA Fire Department said in an alert about the incident that began on September 26.

As of 10 p.m. local time on September 26, the fire department said the blaze could burn for another 24 to 48 hours.

A stretch of roadway linking the two ports to inland trucking routes will remain closed while firefighters monitor the fire. The neighboring Southern California ports make up the busiest container hub in the U.S., handling roughly a third of the nation’s seaborne imports.

The LA port said APM Terminals, Fenix Marine, Everport and Yusen Terminals would be closed on September 27 as work continues around the accident site. TraPac and the West Basin Container Terminal have stayed open, as well as the World Cruise Center, the LA port said.

No injuries were reported, according to the local fire department. LA Mayor Karen Bass said in an emailed statement that an isolation perimeter was established around the fire and a hazardous materials team was on the scene.

The incident comes as dockworkers at major container ports on the Atlantic and Gulf coasts appear increasingly likely to go on strike when their labor contract expires on Monday. The backlog from a one-week work stoppage would take at least four weeks to resolve, according to analysts.

Importers have routed some of their goods to the West Coast to mitigate the risk of disruption of the East and Gulf coast ports, and to get ahead of potential tariff increases from escalating trade conflicts. The LA ports have so far kept up with surging volumes, which are approaching pandemic records. 

As of late September 26, the Port of Long Beach didn’t expect there to be an impact on overall cargo flow, according to a spokesperson.