Tetra Tech Inc., the Pasadena-based engineering, infrastructure and consulting firm, announced a leadership transition last week.

Current company President Roger Argus will become chief executive next month, replacing longtime Chief Dan Batrack, who will have the new title of executive chairman.

The transition is set to take place Feb. 19 at the company’s annual shareholder meeting.

Batrack has served as chief executive of Tetra Tech since 2005. During his tenure, the company has grown from a predominantly U.S- based high-end consulting engineering firm with about 7,200 employees and $1.3 billion in annual revenue into a global powerhouse with more than 25,000 employees and more than $5.4 billion in annual revenue. Concurrent with this growth, Batrack advanced the company’s “leading with science” mantra.

Rising within the ranks

Argus, who is a chemical engineer, has been with Tetra Tech for more than 30 years. He rose through the executive ranks, including a recent stretch in the dual role of executive vice president of corporate development and president of the commercial/international services group. Last October, Argus was promoted to president of the entire company, which has ended up being for a brief stint.

“Dan has built a remarkable organization grounded in scientific excellence, innovation, and a performance-driven culture,” Argus said in a statement.

Argus also outlined some of his goals.

“As we look ahead, I am committed to advancing our ‘leading with science’ differentiation, deepening our global capabilities, and continuing to deliver impactful solutions for our clients and communities around the world,” he said.

One of Argus’ first tasks will be to continue to offset the fallout from Tetra Tech losing its biggest client last year with the closure of the U.S. Agency for International Development. That closure was one of the first and biggest moves of the Elon Musk-led initiative, the so-called “Department of Government Efficiency,” in the early months of President Donald Trump’s second term.

The USAID shutdown cost the company about $1.1 billion worth of contract awards that had been part of the company’s backlog.

Tetra Tech has continued to win contracts from other government agencies, most notably the U.S. Army Corps of Engineers, which has since replaced USAID as the company’s largest single client.