New York (AFP) - Dockworkers at major ports along the US East and Gulf Coasts went on strike Tuesday after last-minute negotiations yielded no new labor contract, a stoppage expected to drag on the world’s largest economy just ahead of the November presidential election.

The International Longshoremen’s Association (ILA) said the walkout by its workers marks the first “coast wide strike in almost 50 years”.

The shutdown would halt shipments of an array of goods from food to electronics and could cost the US economy billions of dollars a week.

“We are prepared to fight as long as necessary, to stay out on strike for whatever period of time it takes, to get the wages and protections against automation our ILA members deserve,” Harold Daggett, who heads the 85,000-member union, said in a statement.

The ILA said it had “shut down all ports from Maine to Texas at 12:01 am on Tuesday” after it rejected a final proposal from the United States Maritime Alliance (USMX) shipping group.

“USMX brought on this strike when they decided to hold firm to foreign-owned Ocean Carriers earning billion-dollar profits” without compensating “workers who perform the labor that brings them their wealth,” Daggett said.

USMX did not respond to a request for comment.

ILA members began walking the picket lines at 14 major ports on the East and Gulf coasts soon after the announcement.

In Boston, dockworkers marched to the port carrying signs that read “no work without a fair contract,” videos shared on social media showed.

CNN broadcast similar images from Philadelphia, while a New York Times video showed Daggett addressing workers on the picket lines.

“We are making history,” he said in New Jersey, as dockworkers held signs saying “Profit over people is unacceptable.”

A possible stoppage had been telegraphed for months, with the odds rising in recent weeks as the two sides described themselves as far apart.

USMX said on Monday it was “hopeful” after the two sides exchanged counter-offers.

However, there was still no deal when the six-year contract expired at midnight.

The walkout marks the ILA’s first since 1977 and follows other high-profile strikes at US automakers, Boeing and other employers.

The contract directly affects about 25,000 ILA members at 14 large US ports, including New York/New Jersey, Boston, Philadelphia, Savannah, New Orleans and Houston.

Oxford Economics estimated that the strike would dent US gross domestic product by $4.5 billion to $7.5 billion per week. The overall economic hit depends on the length of the strike, analysts say.

A lengthy strike could also pose political challenges.

US President Joe Biden, a close ally of organized labor, has so far ruled out federal intervention, citing the need to respect collective bargaining rights.

But business lobbies are sure to amplify calls for action if the strike drags out.

- Fighting automation -

New York Governor Kathy Hochul said on Monday port officials were scrambling to clear out as many items as possible before the impending stoppage.

Other ports, such as New Orleans and Savannah, had offered extended hours in recent days ahead of the deadline.

The union is pressing for protections against automation-related job loss and for hefty wage hikes after dockworkers kept providing essential services throughout the Covid-19 pandemic.

USMX said Monday its latest offer would “increase wages by nearly 50 percent, triple employer contributions to employee retirement plans, strengthen our health care options, and retain the current language around automation and semi-automation.”

Media reports say the ILA is asking for a 77 percent wage increase over six years.

“A port strike would paralyze US trade and raise prices at a time when consumers and businesses are starting to feel relief from inflation,” said Erin McLaughlin, senior economist at the Conference Board.

“There’s no easy Plan B. While shippers have already begun diverting some cargo to the West Coast, capacity for such alternative options are limited.”

New York officials emphasized that any strike would not lead to shortages of basic goods.

“We don’t anticipate shortages of essential goods anytime soon,” Hochul said. “People do not need to rush out to the grocery store and stockpile goods like they did during the pandemic.”

Hochul noted that pharmaceutical products would not be affected because they are typically flown in and not sent by ship. State officials are monitoring other medical supplies but stockpiles were adequate for the foreseeable future, she said.

However, Hochul cited automobiles and semiconductors as items that could be affected more quickly. She also said a lengthy strike could limit the availability of fresh foods such as bananas.