The square pads at the right end of the photo are for stainless steel tanks 20 feet in diameter by 21 feet tall for storing mixed acid for use in the Nitrocotton Production and Nitroglycerine Production Processes. The mixed acid consisted of various mixes of strong nitric acid and Oleum or weak nitric acid and sulfuric acid depending on the finale use of the acid.
The round pads at the bottom of the highlighted area are for mild steel tanks to store sulfuric acid and Oleum. The Oleum was shipped in by rail car from the Oleum Plant in the north east part of the Plant.
The mixed acid was shipped out to the Nitrocotton and Nitroglycerine production areas by rail cars.