A Toyota Motor Corp. plant in southwestern Indiana celebrated on Tuesday the production of its 3 millionth vehicle since opening in 1998, a sign the plant had returned to full speed after natural disasters overseas caused parts shortages during the past year.

The milestone took the form of a silver Sienna minivan, the Evansville Courier & Press reported Wednesday.

"It's a tribute to everyone's hard work," said Norm Bafunno, president of Toyota Motor Manufacturing, Indiana.

Dennis Mewes, who focuses on continuous quality improvement, was among the employees who took part in the celebration. He has worked at the Princeton-area plant, located about 20 miles north of Evansville, for 10 years and said it hardly seems possible the plant already has produced 3 million vehicles.

"I'm just really glad they can do it," he said.

Bafunno said the milestone is especially significant because the Sienna, which is only produced at the plant, was the top-selling minivan in the U.S. in 2011, the first time the vehicle had achieved that mark. The plant was forced to reduce its production schedule because of parts shortages caused by the Japan earthquake and tsunami in March and last fall's flooding in Thailand.

The plant, now operating on maximum overtime, began production in 1998 with the Tundra pickup. It's the region's largest employer, with 4,100 workers and an annual payroll of $288 million.

In November, the Princeton plant began exporting Siennas to South Korea. The plant also exports Sequoia sport utility vehicles to the Middle East, and makes the Highlander SUV.