Longshoremen returned to work at the Mount Pleasant and North Charleston terminals Thursday evening, roughly nine hours after walking off the job amid a labor dispute that threatened to disrupt supply chains across the globe.

The dock workers returned to work about 7 p.m., shortly after a federal judge signed an order, officials said.

Longshoremen walked off the job at Wando Welch and North Charleston terminals Thursday morning. The action was the result of an unspecified number of members of International Longshoremen’s Association Local 1771 Clerks and Checkers being fired for not agreeing to expanded duties outside their labor contract, according to Ken Riley, president of ILA Local 1422 in Charleston.

Riley said the ILA workers were told about new duties on Wednesday. When they declined to accept the added duties Thursday morning, they were terminated, Riley added.

Clerks and checkers are charged with directing trucks that move in and out of the port. They are employed by stevedores, the third-party group that organizes and supervises the work done by longshoremen.

Early Thursday evening, U.S. District Judge David C. Norton signed a temporary restraining order that told ILA members to return to work at the terminals.

The complaint by the S.C. Stevedore Association claims the ILA workers actions are “causing irreparable damage.”

Riley was not available for further comment Thursday night.

Even though the truck flow is determined by ILA workers, some apparently never left the job, since the tractor-trailers were still moving in and out of both terminal gates Thursday.

Some cargo already on dockside is handled by S.C. State Ports Authority workers, which are not part of ILA workforce.

Billy Adams Jr., executive director of the Stevedores Association, was not available for comment. Officials at ILA Local 1771 were also not available.

Riley said members of the Local 1422, which load and unload the shipping vessels, walked off the job Thursday as a sign of solidarity.

“We work in tandem with clerical,” he said. “If they’re not working, we are not working, either.”

Around 9:40 a.m., members of the ILA walked off the job during vessel operations at the Wando Welch Terminal in Mount Pleasant, where one container ship was docked, and North Charleston Terminal, where there were two ships, said Allison Skipper, spokeswoman for the SPA.

The last local dockside work stoppage occurred Dec. 20 when longshoremen at the Wando Welch Terminal delayed unloading a ship for more than an hour in a show of solidarity with workers in third-world countries who labor in dangerous working environments for low pay, officials have said.

The union was joined in its protest by members of Occupy Charleston, who picketed outside the gates of the Wando Welch Terminal.

Work stoppages have a tremendous and often costly impact on supply chains, said Kent Gourdin, director of global logistics and transportation programs at the College of Charleston.

“It can have a pretty significant impact, since stuff is not moving,” Gourdin said. “That means some customers can’t get their goods.”

He added that the supply chain is fragile and it doesn’t take much to have an impact.

Work stoppages have been threatened by the ILA in the past.

The ILA represents roughly 14,500 workers at the Port of Charleston and 14 others that extend south from Boston. The union threatened to strike last year in protest of bitter negotiations about a new master labor contract with the U.S. Maritime Alliance, a group representing shipping lines, terminal operators and port associations.

The strike was averted and sides eventually agreed to a new contract.

There are no impacts to inbound or outbound truck gates at any of the SPA’s terminals at this time, Skipper added in an e-mail.

The two terminals average about 5,000 transactions per day, she said.

Local 1771 has more than 200 members, according to its website.

Riley said Thursday’s issue was unexpected. The ILA and other groups are still hashing out the remaining details in a new local labor contract.

The local contract is separate from the master contract ratified earlier this year by ILA and U.S. Maritime Alliance.

Reach Tyrone Richardson at 843-937-5550 and follow him on Twitter @tyrichardsonPC.