Nippon Oil Corp. said Tuesday that 349 workers, including some at its oil refining subsidiary Nippon Petroleum Refining Co., will voluntarily retire on July 1 under the two companies' early retirement program.

The two companies launched the program last month to cut back their combined workforce of about 5,700 by 500, or about 9 percent.

The number of applicants for the program fell short of the target. Nippon Oil officials said, however, that the two companies would not take any additional steps to boost the number.

The companies will pay special retirement money in addition to regular retirement benefits to the retirees. It will also bear some of the expenses they might incur in finding new jobs, they said.

Nippon Oil will book an extraordinary loss of 12.1 billion yen in connection with the program for the business year ended March 31.