It was at first thought that the existing plants might be able to supply the government’s need of chlorine. The pre-war production averaged about 450 tons (900,000 pounds) per day. The greater amount of this was used in the preparation of bleach, only about 60,000 pounds per day being liquefied. Only a few of the plants were capable of even limited expansion. In an attempt to conserve the supply, the paper mills agreed to use only half as much bleach during the war, which arrangement added considerably to the supply available for war purposes. It was soon recognized that even with these accessions, large additions would have to be made to the chlorine output of the country in order to meet the proposed toxic gas requirements. After a careful consideration of all the factors, the most important of which was the question of electrical energy, it was decided to build a chlorine plant at Edgewood Arsenal, with a capacity of 100 tons (200,000 pounds) per day. The Nelson cell was selected for use in the proposed plant. During the process of erection of the plant, the Warner-Klipstein Chemical Company, which was operating the Nelson cell in its plant in Charleston, West Virginia, agreed that men might be sent to their plant to acquire the special knowledge required for operating such a plant. Thus when the plant was ready for operation, trained men were at once available. [Illustration: FIG. 19.—Chlorine Plant, Edgewood Arsenal.] [Illustration: FIG. 20.—Ground Plan of Chlorine Caustic Soda Plant, Edgewood Arsenal.] The following description of the plant is taken from an article by S. M. Green in _Chemical and Metallurgical Engineering_ for July 1, 1919: “The chlorine plant building, a ground plan of which is shown in Figure 20, consisted of a salt storage and treating building, two cell buildings, a rotary converter building, etc. In connection with the chlorine plant, there was also constructed a liquefying plant for chlorine and a sulfur chloride manufacturing and distilling plant. “The salt storage and treating building was located on ground much below the cell buildings, which allowed the railroad to enter the brine building on the top of the salt storage tanks. These tanks were constructed of concrete. There were seven of these tanks, 34 feet long, 28 feet wide and 20 feet deep having a capacity for storing 4,000 tons of salt. There would have been 200 tons of salt used per day when the plant was running at full capacity.