1.2 Black Ink Process Description
The US Ink East Rutherford plant (built in the 1920s) manufactures both black and color oil-based ink for various commercial clients. A key step in the ink production process is mixing solid and liquid ingredients to produce a liquid suspension. The mixing operation for black ink ingredients is performed in the pre-mix room, where the October 9, 2012, incident occurred. Figure 1 depicts a simplified plan view of the pre-mix room containing three large mixing tanks in which the various ink formulations are made. The room is 30 feet wide by 17 feet deep and has cinder block walls up to the 30-foot ceiling height. The black ink manufacturing process at US Ink involved the pneumatic transfer2 of bulk solid powder under vacuum to one of three mixing tanks, labeled as 106, 206, and 306 (T-106, T-206, and T-306, respectively).