One of the first companies to locate at Chattanooga's Centre South Riverport is closing part of its operations and laying off about 30 people, an official said Monday.

NA Industries, which has a chemical plant at the site off Amnicola Highway, is moving production of super absorbent polymers from Chattanooga to the Houston area where the business has newer facilities, said Jim Horton, the company's human resources manager.

However, plans are to continue production in Chattanooga of fine chemicals used as detergent additives and to strengthen cement, he said.

The layoffs, slated to take effect Friday, will leave the local plant with about 40 workers.

Horton said the Chattanooga super absorbent polymers unit, which made materials used in baby diapers, actually ceased operations in May 2012. But it was temporarily restarted over the past several months to meet an unusual customer demand, he said.

The company is reviewing the possibility of adding new product in Chattanooga in the future, Horton added.

"There are ongoing studies," he said. "They're looking at the feasibility."

NA Industries, which has operated in Chattanooga for about 22 years, likes the production facility and the city's workforce pool, Horton said.

J.Ed. Marston, the Chattanooga Area Chamber of Commerce's vice president of marketing, said he is sorry about the job losses but encouraged that the company will continue to operate in Chattanooga with the prospect of future expansion.

Meanwhile, work has begun at the Riverport on a $4 million tractor assembly and distribution facility by Southeast Mahindra USA.

The new plant will range from 40,000 to 60,000 square feet and accommodate 10 shipping and receiving docks and six assembly lines with overhead cranes, according to Randy Topping, who is shifting Mahindra assembly and distribution from his Chattanooga Tractor and Equipment dealership on Polymer Drive.

The facility also will include warehouse, office space and training areas on a 10-acre tract and is projected to more than double the staff size to about 100 employees.

Contact Mike Pare at mpare@timesfreepress.com or 423-757-6318.