Engility Holdings has secured a $248m contract to provide support services to the Defense Threat Reduction Agency (DTRA).
The DTRA's aim is to counter chemical, biological, radiological, nuclear and high-yield explosive (CBRNE) threats.
Engility will provide technical consulting and systems engineering to the agency, working alongside its research and development directorate in the US Department of Defense's (DOD) Countering Weapons of Mass Destruction (CWMD) Combat Support Agency.
The contract includes one base year and four additional one-year options, in the second quarter of 2016.
Engility CEO Lynn Dugle said: "This award continues a nearly 50-year partnership between Engility and DTRA to provide high-end chemical, biological, radiological, nuclear, and explosive (CBRNE) technical and acquisition programme support.
"DTRA performs indispensable work that safeguards the American people and we are proud to partner with them on this critical mission."
In February, the company secured a position on a $900m contract to support the DoD's Joint Program Executive Office for Chemical and Biological Defense (JPEO-CBD).
The indefinite delivery / indefinite quantity (IDIQ) contract required the company to provide chemical, biological, radiological and nuclear (CBRN) support to US military services.
It covers the provision of logistics, supply chain management, and maintenance support services for JPEO-CBD for a period of three years, and features an additional one-year option.