A deal has been struck that for now averts a strike by 14,500 longshoremen at major ports on the East Coast and Gulf of Mexico.

A federal mediator announced Friday that an expired contract for workers in the International Association of Longshoremen would be extended for another 30 days while negotiations continue.

The longshoremen had been preparing for a possible strike Sunday that would probably have crippled operations at ports that handle about 40 percent of all U.S. container cargo.

The mediator says there have been major steps forward toward resolving the dispute.

Background

A strike could've shut down ports from Florida to Maryland - including the Port of Tampa.

The International Longshoremen's Association couldn't reach a contract deal with the United States Maritime Alliance, and the current one was supposed to end at midnight.

If the ILA strikes, nearly 15,000 workers at 15 ports will go on strike.  Four ports would be affected in Florida: Miami, Fort Lauderdale, Jacksonville and Tampa.

Port leaders in Maryland say the damage of a shutdown would reach well beyond the docks.

"Everybody from your mom and pop retailer to your farmer, to the trucking company who has to go in and pick up the containers at the ports," Maryland Port Administration spokesman Richard Scher said. "So this is going to be felt not just at the local economy at the ports, but nationwide for everybody else who relies on these ports to move their commerce."

Gov. Rick Scott said shutting down the ports is not an option, as too many livelihoods depend on them.  On Thursday, he posted on Twitter that he wants President Barack Obama to step in.

"If a strike or a lockout occurs at that time, Florida’s largest ports could be shut down, sending shockwaves through jobs all across our state - including truck driver jobs, manufacturing jobs, warehousing jobs - and many jobs beyond the ports themselves," Scott said in a press conference on Thursday. "A shut down of Florida ports is simply not an option for Florida families." 

Scott, who was joined by the directors of Florida's ports, has called on President Obama to invoke the Taft-Hartley Act, which gives the president the power to keep the ILA working even if they cannot come to an agreement.

Florida ports add up to more than 500,000 jobs in the Sunshine State, as well as $66 billion in economic activity, the governor's office said.

Port Canaveral

Brevard County's Port Canaveral is not yet heavily in the cargo business, with only a miniscule percentage of the port's business being in cargo. The popular cruise ship port, however, would not stay unscathed during a longshoreman strike.

Large cruise ships require cargo to supply them. Those provisions often come in container cargo.

Port Canaveral is the home port of several large cruise ships, including the Disney Cruise Lines' Dream and Fantasy, Royal Caribbean's Freedom of the Seas, and Carnival's Dream.