EL DORADO, Ark. (AP) _ Tetra Technologies Inc. broke ground Thursday on a new $100 million chemical plant in El Dorado, where the company will produce calcium chloride.

The plant will employ about 50 people when it opens next year, officials said, and in the meantime is expected to generate about 400 construction jobs. Tetra provides products and services to the oil and gas industries.

Based in The Woodlands, Texas, the company had previously said it would build the plant near Magnolia. Instead, Tetra announced last year it would put the facility at El Dorado. The plant will be Tetra's second in Arkansas. The company opened a zinc bromide plant in West Memphis in 1987.

The new plant will collect saltwater from underground and process the brine into calcium chloride for use in drilling and in other products.

Arkansas is undergoing a boom in gas drilling in the Fayetteville Shale play in the northern and central portions of the state, though south Arkansas has long been home to the petrochemical industry.

Gov. Mike Beebe said the El Dorado area has the workers and infrastructure that Tetra will need.

"Tetra's arrival in Union County will continue the strong tradition of oil-and-gas investment in south Arkansas," Beebe said. "Let's everybody celebrate, but let's put at the top of the list the people of Union County. They collectively said that they weren't going to be denied and they were going to create the opportunity for another successful company to come to South Arkansas."

Jim Tidwell, general manager of Tetra's south Arkansas operation, said the area's healthy business environment helped attract Tetra.

Union County Judge Bobby Edmonds, the county's top elected administrator, said he very much appreciated the company's efforts.

"The management at TETRA has been easy to work with and we look forward to seeing their investment take shape over the next year and a half," Edmonds said. "We look forward to a long, successful and prosperous relationship."

Tetra had 2007 sales of $982.5 million. As of 2006, the company had more than 2,500 employees spread among five continents.

When in operation, the Union County facility is expected to produce 400,000 tons of liquid calcium chloride annually, plus 120,000 tons a year of dry-flake calcium chloride and 210,000 tons of salt.

Information from: El Dorado News-Times, http://www.eldtimes.com

Copyright 2008 The Associated Press.