The Del Amo Superfund site is approximately 280 acres in area, and sits at the junction of the 405 and 110 freeways in Los Angeles, near the cities of Carson and Torrance. According to Works Progress Administration (WPA) land use maps from 1937, the former Del Amo site was composed almost entirely of undeveloped cropland and pasture. Aerial imagery for the Del Amo site shows that the area remained undeveloped through the year 1941, and by 1946 was developed for industrial manufacturing during World War II (See Figure 4). Specifically, the former Del Amo site operated as a synthetic rubber manufacturing plant consisting of three separate processing plants: a styrene plant operated by Dow Chemical Company, a copolymer plant operated by U.S. Rubber, Goodyear Tire & Rubber Co. and others, and a butadiene plant operated by Shell Oil Company.
By 1943, the Del Amo site was fully developed as rapid industrialization occurred at great scales to support the war effort.
According to the April 27th, 1944 edition of the Torrance Herald newspaper, “construction of the plant was begun in September of 1942 and in less than nine months, the first styrene was produced. A month later, the plant was stepped up to full production with a capacity sufficient to provide enough styrene to make 54,000 ordinary automobile tires daily”. The entire operation of synthetic rubber manufacturing at the plant was directed by the California Synthetic Rubber Project, which integrated individual chemical processes by way of above and underground pipelines in a “continuous production flow” to create large volumes of Buna-S synthetic rubber (also known as Government Rubber-Styrene Type) (Torrance Herald 1944, 2-C). The Buna-S rubber was preferable to natural rubber due to more efficient processes and higher yield, which were essential to war material production demands during World War II.
The process of producing synthetic rubber consisted of manufacturing styrene and butadiene separately and then piping the chemicals to the copolymer plant for polymerization, which produced the synthetic rubber product. The rubber is then formed into 75-pound bales and shipped to different factories (Torrance Herald 1944, 2-C). See figure below for the “Steps in Production California Synthetic Rubber Project” from the Herald feature story about the various processes involved in processing and distributing the Buna-S product.
Throughout its operations, chemicals and waste products were released into the soil and groundwater beneath the site originating from leaks in pipelines, storage tanks, and processing units. In addition, waste was transferred to separator units, and settled sludge from the units was disposed of off-site or in a waste area in the south-west portion of the Del Amo site property (known as the Waste Pits Area). The Waste Pits Area covers approximately 4 acres and included four unlined evaporation ponds and six unlined waste pits. The release and disposal of onsite waste resulted in contaminated soil and groundwater underneath the plant.
The chemicals used by the plant include benzene, ethylbenzene, propane, butylene, styrene, and 1,3-butadiene and others. In 1972, by the time the plant was permanently closed, the unlined pits and ponds that were still open were covered in soil and surrounded by a double chain-link fence. Most of the parcels on the former facility site have been redeveloped as an industrial park . Some 200 businesses occupy the site including a Holiday Inn, Coca Cola Bottling, University of Redlands, Herbalife International, Aerotek, FedEx, and restaurants, to name a few.
Read more about the “pieces” of Del Amo, referred to as “Operable Units” (OUs) by the EPA to maintain coordination in cleaning up different portions of the site.