BOSTON — Weeks after a critical West Coast port complex was crippled by a few hundred striking workers, the East Coast is bracing for a possible walkout numbering thousands that could close 15 ports from Massachusetts to Texas.

The latest talks between shipping companies and dockworkers broke down Tuesday, less than two weeks before the contract expires Dec. 29, leading to worries a strike was inevitable.

The National Retail Federation wrote to President Barack Obama this week to ask him to use “all means necessary” to head off a strike, which they fear could have catastrophic ripple effects nationwide.

“We foresee this as a national economic emergency, to be honest,” said Jonathan Gold, the group’s vice president of supply chain and customs policy.

Ingrid Hirstin Lazcano, founder of the Los Angeles-based Andean Dream LCC, said a strike on the East and Gulf coasts could bankrupt her company, which sells soups, pasta and other products made from quinoa, a grain, grown in the Bolivian Andes.

The company has two containers shipped monthly to both Los Angeles and Philadelphia, and Lazcano said she’s still recovering from the eight-day strike of 450 clerical workers at the Los Angeles-