The scientists of Gentek worked for an organization known as Blackwatch. The employees of this facility were always under surveillance by them. This facility also held Elizabeth Greene, a highly unstable test subject who's body produced new viral strands each day. Many experiments were conducted with these new strands.
Greene was situated on the 51st floor of the facility. She was eventually freed by Alex Mercer.
Despite the Infected's considerable control within Manhattan, it appears that the Gentek building remains relatively unscarred, thanks to Blackwatch's protection. A military base has been erected within the building's surroundings, with both Blackwatch and U.S. Marine Corps infantry constantly repelling the Infected - at a high cost, given the suicidal environment of the Red Zone after the Second Outbreak.
James Heller was forced to employ Juggernauts to break down the fortified steel that blocked the entrance to the Gentek headquarters. Once inside the building, Heller encounters Colonel Rooks and his men.