An environmental testing company has chosen Darien for its new headquarters, settling into a space at 19 Old Kings Highway South.

TestAmerica, a privately owned business that has 35 laboratories and 40 service centers, opened its main office in late September in a 4,600-square-foot space in a building owned by Forstone Capital LLC.

The Darien site was chosen for its proximity to senior leadership and access to transportation, according to a company statement, which noted that CEO James Hyman lives in Stamford, and Chief Financial Officer Benjamin Erwin lives in Darien.

Stamford resident Constance Hubbard has been hired as vice president of human resources.

Jeffrey Gage, managing principal of the Norwalk office of CresaPartners, which represented TestAmerica in its site search, said it has been operating with a virtual headquarters.

"They felt they needed a home base. The idea is having a beachhead where they can recruit from," said Gage, who worked with Rich Opalenik of the CresaPartners Norwalk office. "We're managing a portfolio of $1.2 million square feet for them."

Gage said the space will eventually house 15 to 20 employees.

The 45,513-square-foot, three-story building, purchased by Forstone Capital eight months ago, is a block from the Darien train station and near Darien's downtown, an important location as Forstone fills the property, said George Walker, executive vice president of the Stamford office of Jones Lang LaSalle, which represents Forstone.

Forstone is remodeling the building and improving the landscaping and parking lot, he said.

"Generally, the occupancy level is about 50 percent, but we've had a lot of interest from companies looking to take advantage of the downtown amenities and Metro-North. Our prospect velocity has been good," Walker said, commenting that Trammochem will soon move to 17 Old Kings Highway South in Darien, and JetBlue will then finish moving to its New York offices. "That gives us the opportunity reposition the building."

Carol Wilder Tamme, president of the Darien Chamber of Commerce, welcomed TestAmerica, noting that Old Kings Highway is a block from the busy Post Road.

"Expanding the `business buzz' from the Post Road into another block will be beneficial for restaurants and all other businesses that support people employed in our central business district," she said.