The Worker Adjustment and Retraining Notifications (WARNs), which were issued last Thursday, are required under federal law for manufacturing facilities with more than 200 employees. The WARNs said that the plant could close within 60 days.

According to Marc Roper, Vice President of Sales and Marketing at SCHOTT Solar Inc., the decision to issue the WARNs was entirely related to the company's inability to lock up enough silicon for cell production. Roper said that SCHOTT had no intentions of pulling out of the U.S. photovoltaic (PV) market.

"This is all about the silicon supply situation. It is definitely not related to any consideration of the market in the U.S.," said Roper. If the plant closes, SCHOTT Solar, Inc. will keep its headquarters in Roseville, California, and continue shipping modules into the country from its European facilities.

The potential closing of the 15-megawatt (MW) capacity manufacturing plant is a grim reminder of the impact that silicon constraints are having on the PV market in the U.S. and around the world. Many companies have had to scale back operations because of the silicon shortage.

"SCHOTT -- like many other solar manufacturers right now -- is having a tough time identifying adequate supplies of silicon. The company doesn't have enough silicon to run all its facilities, and won't until 2008," said Roper.

SCHOTT European manufacturing is not up to capacity either, he said. The company currently has four manufacturing facilities in Europe and one in the U.S. with a combined capacity of 130 MW. But because the Billerica plant is the oldest and least efficient of all SCHOTT's facilities, the company will close it if necessary.

If the plant closes, SCHOTT could sell it to another solar company with enough silicon supply to resume production. Roper said it was too early to comment on any specific negotiations.