SDMS DOCID# 1144550 Del Amo Superfund Site Del Amo Superfund Site Los Angeles, California Los Angeles, California

U.S. Environmental Protection Agency z Region 9 z San Francisco, CA z January 2011 Information Repositories EPA Contacts 2nd 5-Year Review at Torrance Civic Center Library Dante Rodriguez 3301 Torrance Boulevard Del Amo Waste Pits Completed (415) 972-3166 Torrance, CA 94952 [email protected] Background (310) 618-5959 Site Status Report Th e Del Amo Superfund Site, located in Los Angeles, Cali- Carson Public Library fornia, encompasses approximately 280 acres in a narrow strip Alejandro Díaz (Spanish Speaker) 151 East Carson Street of the city known as the Harbor Gateway. Th e portion of Carson, CA 90745 (415) 972-3242 or (800) 231-3075 the Site subject to the fi ve-year review-the Waste Pits OU- (310) 830- 0901 2-occupies approximately 4 acres at the southern end of the [email protected] Site. Th e Del Amo synthetic rubber plant operated from approximately 1943 to 1972, and consisted of three separate plants dedicated to the production of styrene, butadiene, and USEPA Web site at www.epa.gov/region09/delamo rubber. During its early operations, waste was disposed of A Spanish version of this fl yer is also available, see contact information. at four unlined evaporation ponds and six unlined waste pits located in the area now identifi ed as the Waste Pits OU-2. Results from environmental investigations showed that the waste material had contaminated adjacent soil with volatile organic compounds (VOCs) and semivolatile organic com- pounds (SVOCs). Benzene, a VOC and known human car- cinogen, is the hazardous substance detected most frequently United States Environmental Protection Agency, Region 9 FIRST-CLASS MAIL and at the highest concentrations at the Waste Pits OU-2. 75 Hawthorne Street (SFD-6-3) POSTAGE & FEES Among the SVOCs, naphthalene has been detected at the The United States Environmental San Francisco, CA 94105 PAID highest concentrations and at the greatest frequency in waste Protection Agency (USEPA) completed Attn: Alejandro Díaz (Del Amo 6/10) U.S. EPA material and soil. Groundwater is impacted by the VOCs and Permit No. G-35 SVOCs (particularly benzene, ethylbenzene, naphthalene, and the second five-year review of the phenol). Del Amo Waste Pits Operable Unit Offi cial Business Selected Cleanup Remedies (Waste Pits OU-2) at the Del Amo Penalty for Private Use, $300 In the 1997 Waste Pits OU-2 Record of Decision (ROD), the Superfund Site (Site) in Los Angeles, Address Service Requested selected remedy included: California in September 2010. Superfund ■ Installation of a multi-layer impermeable cap guidance requires a review of cleanup over the waste pits; actions every five years if the levels of ■ Installation of surface water controls to prevent ponding of water on the cap and run-off to adjacent properties; contaminants remaining at a site do not ■ Installation and operation of a soil vapor extraction/ allow unrestricted use of the property. in-situ bioventing technology (SVE/IBT) system; The Del Amo review concluded that the ■ Installation of security fencing around the above- cleanup remedy and deed restrictions ground are protective of human health and the SVE/IBT treatment units; environment, as is briefly summarized in ■ Land use restrictions; and this Fact Sheet. ■ Long-term operation, monitoring, and maintenance (OM&M). 2 Del Amo Waste Pits: 2nd 5-Year Review Completed Del Amo Waste Pits: 2nd 5-Year Review Completed 3

Current Status of the Cap and Surface Th e vapor extraction wells successfully capture contaminants Water Controls that could migrate down to the groundwater or laterally out Five -Year Five -Year Review from beneath the cap. Th e system has proven eff ective in Since installation, the cap and surface water controls have degrading and removing contaminants from the subsurface, Review Findings Recommendations been routinely inspected and measured for settlement to as seen by the steady decrease in concentrations of incoming ensure the cap remains intact and that the surface water VOCs between 2005 and 2009. Th e SVE/IBT system is The remedy is effectively preventing direct human No issues that affect the protectiveness of this controls adequately collect and convey rainfall. Th e cap’s degrading and adsorbing benzene at an estimated average of contact with contaminants at the Waste Pits OU-2 remedy were identified through this second five- gas collection and treatment system (GCTS) is monitored 65 pounds per day. By the end of the 2009 operational year, and is preventing contaminant migration from the year review. As such, there are no associated to ensure that the emission standard of 5 parts per million approximately 70,430 pounds of benzene had been removed soil to the groundwater. The cap, surface water recommendations. However, several monitoring by volume (ppmv) is not exceeded. from the Waste Pits OU-2 since system startup on August 6, controls, and security fencing were completed items identified during the review require follow- Th e cap and its GCTS, surface water controls, and security 2006. Of this mass removed, an estimated 53,849 pounds in February 2000. The cap is in good condition up actions: fence are functioning as intended in the Waste Pits ROD. had been removed through biodegradation and 16,582 and continues to prevent human contact with ■ The methodology for measuring progress pounds through carbon adsorption. Based on visual inspections over the past fi ve years, there contaminants. The surface water control and towards achieving the soil cleanup standard are no problems with the cap or surface water controls that Quarterly monitoring of the perimeter wells demonstrated security fence are functioning as intended by the needs to be clearly established. require repair. Vegetative cover on the cap is well estab- that contaminated soil vapors were not migrating beyond Waste Pits ROD. The deed restrictions prohibit lished and maintained, with no observed evidence of ero- the cap boundaries. ■ Groundwater monitoring needs to be use of the site for hospitals, schools, day care, or performed consistent with the 2008 OM&M sion, slope instability, or settlement. Th e concrete V-ditch System components, including wells, piping, blowers, treat- residences and prohibit disturbance of the cap. surface drainage channels bordering the cap on the northern Manual ment units, etc., are in good working condition. Th e fencing The SVE/IBT system was in full operation by August and southern edges are in good condition. Caulking at surrounding the system enclosure, the overhead canopy, and to update the SVE/IBT performance the joints along the concrete-paved ditches is intact and 2006, and is functioning as intended by the Waste standard. the concrete pad are well maintained and in good condition. Pits ROD. The system has completed its third in suitable condition. Debris and sediment have not been ■ Vapor concentration gradients at the observed along the drainage channels or in the catch basins. Land Use Restrictions year of full operation during this five-year review clustered vapor monitoring wells need to be Th e retaining wall along the southern edge of the cap is period. Th e Waste Pits ROD specifi ed environmental deed restric- evaluated. intact and in good condition, with no observable damage or tions as a component of the selected remedy. Such restric- areas needing repair. tions are intended to prevent residential use or any other These monitoring items do not affect the Th e GCTS is eff ectively collecting and treating vapors from use that could impact the integrity of the cap. Th e Site’s protectiveness of the remedy, rather they will be below the cap, consistently reducing benzene concentrations property owners are responsible for conducting the ongoing used to help determine how long the cleanup to below the emission standard of 5 ppmv. VOC concen- monitoring and for enforcing the restrictions. Current deed system will need to be operated. trations entering the GCTS before treatment ranged from restrictions and monitoring procedures comply with the 0 to 25.6 ppmv, and have declined steadily during this fi ve- ROD requirements. year review period. Current Status of the SVE/IBT System Th e system has completed its third year of full operation What Happens Next? during this fi ve-year review period. Th e objective for the Th e selected remedy is proving successful in removing VOCs from the soil and in protecting the groundwater at the SVE/IBT system is to remove VOCs from the soil in order Del Amo Waste Pits OU-2 Site. Th e systems will continue to be operated, the monitoring issues will be resolved, and to prevent them from entering the groundwater or moving another Five-Year Review will be conducted in 2015. out from beneath the impermeable cap. EPA concludes that the SVE/IBT System is functioning as intended in the Information Repositories Waste Pits ROD and meeting the objective. Th e Five-Year Review Reports and other documents related to cleanup activities for the Del Amo Superfund Site Waste Pits OU, are available to the public at the public libraries and web site listed below:

Torrance Civic Center Carson Public Library EPA Superfund Records Center Library 151 East Carson Street 95 Hawthorne Street, Room 403 3301 Torrance Boulevard Carson, CA 90745 San Francisco, CA 94105-3901 Torrance, CA 94952 (310) 830- 0901 Telephone: (415) 536- 2000 (310) 618-5959 USEPA Web site at www.epa.gov/region09/delamo Fax: (415) 764-4963 A Spanish version of this fl yer is also available, see contact information.