NEW YORK — Aluminum giant Alcoa and its largest union extended their deadline to negotiate a new contract covering thousands of employees.

The Pittsburgh-based company and the United Steelworkers Union are negotiating over compensation for new workers, health care benefits and work flexibility.

Negotiations began in mid-April. The current contract was to have expired at 1 a.m. Monday, but the parties agreed to an 11-hour extension.

The contract covers about 5,400 employees at 10 plants. The plants produce raw aluminum that is used in products such as beverage cans, cars and planes.

An Alcoa spokesman said the company deployed salaried workers from across the country to run the plants in case of a strike.

The last time the steelworkers union went on strike at Alcoa was in 1986.