A liquified gas production facility in Bethlehem has expanded its capacity by 600 tons a day, the two partners in the plant said today.

The plant, East Coast Oxygen, is owned jointly by Air Products & Chemcials Inc. of Allentown and Linde North America of Murray Hill, N.J.

The companies said the plant now is one of the largest liquified nitrogen, oxygen and argon production sites in the United States. Its gases are used for food chilling and freezing, chemical production and metals manufacturing.

The plant began operation in 2000.