NEW YORK, May 20 (Reuters) - Exxon Mobil XOM.N said on Tuesday it was working to resolve an issue at its 275,000-barrels-per-day refinery in Joliet, Illinois.

The Houston, Texas-based company reported an equipment failure involving its process unit boiler that resulted in a gas release at the Joliet facility, according to a filing.

"We are working to resolve an operational issue and expect to meet customer commitments," a company spokesperson said.

Exxon Mobil did not disclose the cause of the issue or the impact.

The refinery had reported a separate operational issue in late April.

The Joliet refinery can produce about 11 million gallons a day of gasoline and diesel fuel, according to the company's website.

(Reporting by Nicole Jao in New York; Editing by Jamie Freed)

((Nicole.Jao@thomsonreuters.com; Twitter/X: @ByNicoleJao; +1 646 540 2216;))