Roush Technologies is a biotechnology firm connected to the military industrial complex. It is a front company for the Syndicate, and is involved in work on the human-alien hybrid project. The company also has a political arm that is involved in lobbying activities. At least some Department of Defense employees were being compensated for their work by Roush, including Michael Kritschgau. It is unclear, however, what sort of work he may have been doing for them. Section Chief Blevins, the Syndicate's "mole" in the FBI, also worked for Roush. Skinner goes to Congress to obtain information exposing Blevins in front of The First Elder who watches him on TV and after Mulder uncovers him, we knew Blevins also received payment from Roush/The Syndicate (TXF: Redux) (TXF: Redux II).
In 1998 a Roush employee named Sandy was working with the alien Purity virus in their Phoenix, Arizona location. In the process, he accidentally exposed himself to the virus, possibly via a needle prick. He became infected, and soon after gestated an alien lifeform which burst from his chest and went on to kill another Roush employee before fleeing the area (TXF: The Beginning).
Dr. Eugene Openshaw was also affiliated with Roush. He and his colleagues drove a Roush company van to a trainyard where they were conducting gene therapy on Cassandra Spender inside one of the boxcars used by the Syndicate. (TXF: Two Fathers).
The status of Roush after the apparent destruction of the Syndicate is unclear.