The salt industry during the 1970's encountered several expansions, closures, and consolidations of salt operations. Higher energy costs because of the Arab oil embargo in October 1973 and the cost of implementing pollution abatement equipment to comply with antipollution legislation contributed to the closure of seven of the eight remaining synthetic soda ash plants in the United States that used significant quantities of salt brine. Small rock salt and solar salt producers were acquired by medium-sized companies in order to be competitive with the major salt companies, all of which had foreign subsidiaries to rely on to supply less expensive imported salt.
During the 1980's, salt was criticized by the environmental and medical communities. Several studies indicated that the excessive use of salt for highway deicing caused damage to roadside vegetation and contributed to high levels of sodium measured in ground water supplies. Salt also contributed to the corrosion of automobiles and metal bridge surfaces and road reinforcement rods. A nationwide campaign was initiated by the salt industry to educate snow equipment operators on when and how much salt to apply to highways. Salt was also reported to be the cause of hypertension in humans, and efforts were made to reduce the quantity of salt added to food by the food processing industry. Although salt for human consumption is only about 3% of total domestic demand, only about 200,000 metric tons of the 2.1 million metric tons used annually in food processing was lost because of changes made by the food processing industry. By the late 1980's, more thorough studies were made to show that only a small segment of the population was "salt sensitive" and that the balance of the population was not necessarily at risk. Rather than reversing their earlier findings, medical researchers took the position that anything in excess was unhealthy.
The environmental issue pertaining to using chlorine-base compounds began in 1990. Chlorine used in pulp bleaching and in treating municipal water supplies reportedly produced carcinogenic compounds. Its use in chlorofluorocarbons contributed to ozone depletion in the upper stratosphere. Because chlorine is produced from salt, the problem will reduce the quantities of salt used. The remainder of the decade will continue to emphasize concern for the environment.
- Table 1.--U.S. historical salient salt statistics
- Table 2.--Salt production in the United States
- Table 3.--Comparison of U.S. salt production and demand
- Table 4.--U.S. exports of salt
- Table 5.--U.S. imports for consumption of salt
- Table 6.--Salt sold or used by producers in the United States, by State
- Table 7.--Time-value relationships for various types of salt, 1970-90
- Table 8.--U.S. Salt supply-demand relationships