PRELIMINARY PUBLIC HEALTH ASSESSMENT
DEL AMO FACILITY
LOS ANGELES, LOS ANGELES COUNTY, CALIFORNIA
Located in Los Angeles, California, the 280-acre Del Amo hazardous waste site contains contamination resulting from a synthetic rubber manufacturing facility consisting of three plants, which formerly operated on the site from 1943 through the mid to late 1960s. The handling, storage, and disposal practices of the raw materials, products, and by-products of the synthetic rubber manufacturing facility appear to have resulted in contamination of soil, groundwater, and air. Primary contaminants associated with a 3.7-acre waste disposal area located near the southern boundary of the Del Amo site include volatile aromatic hydrocarbons (such as benzene and ethylbenzene) and polycyclic aromatic hydrocarbons (such as naphthalene, benzo(a)pyrene, phenanthrene, and chrysene). The U.S. Environmental Protection Agency (EPA) is currently reviewing information available on the former waste disposal area and is developing a workplan for a remedial investigation, feasibility study, and risk assessment to fully characterize the extent of contamination and to assess alternatives for clean-up of the entire 280-acre site.
Based on the information available for review, CDHS and ATSDR conclude that the Del Amo site presently poses an indeterminate public health hazard to nearby residents and workers. Exposure to site-related contaminants found in air, mainly volatile aromatic hydrocarbons, occurred in the past and may still be occurring to residents and workers in the area through inhalation. Past air releases, especially of benzene, during disturbed site conditions were at levels of health concern. The potential for soil gas migration and release to ambient and indoor air also represent a serious public health concern. Past, present, and future exposure to site-related soil contaminants, such as polycyclic aromatic hydrocarbons, may be likely for residents and workers through ingestion and skin contact.
Currently available information does not allow for full determination of exposures to contaminants from the site, as well as other non-site related sources in the area, such as industrial facilities and vehicular emissions. Thus final conclusions of possible health effects can not presently be made. Findings from past studies indicate residents in the area reported experiencing skin irritation/rashes as well as irritation of the eyes, upper respiratory tract, and throat. Although these symptoms are commonly associated with some of the contaminants found at the Del Amo site, information is insufficient for determining whether the contaminants released from the Del Amo site or other sources in the area are responsible for the symptoms experienced by the residents.
Exposure to contaminated groundwater has not been shown to have occurred to date. However, contamination in the shallow aquifers could move into the deeper aquifers used for drinking water and result in human exposure at levels of health concern. Preventive measures must be taken to prevent contaminants in the shallow groundwater from moving into deeper aquifers.
Further determination of the extent of contamination in the groundwater underneath residences south of the site and other buildings on top of the site and further characterization of soil gas migration are needed. Indoor air monitoring will be needed to determine actual concentrations which can then be used to assess public health significance of contaminants present.
CDHS and ATSDR have made recommendations to: 1) reduce and prevent exposure to contaminants; 2) better characterize the site; 3) implement follow-up health activities; and 4) address community health concerns.
The data and information developed in the Del Amo Preliminary Public Health Assessment have been evaluated by the ATSDR Health Activities Recommendation Panel (HARP) for follow-up health actions. Completed and potential exposure pathways have been identified for nearby residents and workers. However, the available information does not allow for an accurate determination of exposure levels. Releases from other known sources in the area may also be contributing to the environmental contamination in the area and interfere with the estimation of exposure to contaminants released from the Del Amo site. In coordination with other agencies, CDHS will provide ongoing community education in appropriate languages to the communities near the site about possible health effects from site related contaminants and ways to prevent, cease, or reduce exposures.
HARP determined that available health data, including a health effects investigation and a review of vital statistics and cancer registry information, indicate residents living near the Del Amo site did not appear to experience increased rates or unusual patterns of cancer or death. Residents do report experiencing several irritative symptoms, including skin irritation/rashes, and irritation of the eyes, nose, and throat. Given the fact that more accurate exposure levels cannot be determined due to insufficient environmental data, no further health actions are warranted at this time.
ATSDR and CDHS will coordinate with the appropriate environmental agencies to develop plans to implement the cease/reduce exposure and site characterization recommendations contained in this preliminary public health assessment. CDHS will also coordinate with other agencies to provide community education in appropriate languages to the communities near the site about possible health effects from site related contaminants and ways to prevent, cease, or reduce exposures.
EPA intends to approach the issue of migration of subsurface gas into homes and other structures in a phased manner, by first taking soil gas samples in the vicinity of several homes and other buildings. In the event that these samples show elevated levels of soil gas, EPA will then consider indoor air monitoring. However, EPA notes that given this site is in an area known to have significant air pollution problems, it may be difficult to distinguish between sources of indoor ambient air contamination.
ATSDR and/or CDHS also plan to review additional data as they become available and determine from the review what further actions are needed to protect public health.
Under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR), the California Department of Health Services (CDHS), has prepared this preliminary public health assessment to evaluate the public health significance of the Del Amo site. CDHS and ATSDR will determine whether health effects are possible and will recommend actions to reduce or prevent possible adverse health effects. ATSDR, located in Atlanta, Georgia, is a federal agency within the U.S. Department of Health and Human Services and is authorized by the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) to conduct health assessments at hazardous waste sites. Preliminary public health assessments are performed when limited data preclude a complete assessment of public health risk. A full public health assessment will be performed, if considered appropriate, when the environmental characterization is completed and provided to ATSDR for consideration. This preliminary public health assessment for the Del Amo site is based on a review of available environmental data, health data, community concerns, and information obtained from site visits and consultation with involved agencies and the public.
The U.S. Environmental Protection Agency (EPA) proposed the Del Amo site to be listed on the National Priorities List (NPL) in July 1991. This list informs the public of uncontrolled hazardous waste sites that warrant further investigation to determine if they pose risks to public health or the environment. Clean-up activities for sites included on the NPL can be paid for through funds established by CERCLA.
EPA proposed the Del Amo site be listed on the National Priority List of hazardous waste sites because of contamination resulting from a synthetic rubber manufacturing facility consisting of three separate plants, which formerly operated on the site from 1943 through the mid to late 1960s. The handling, storage, and disposal practices of the raw materials, products, and by-products of the synthetic rubber manufacturing facility appear to have resulted in contamination of soil, groundwater, and air. Primary contaminants associated with the Del Amo site include volatile aromatic hydrocarbons (such as benzene and ethylbenzene) and polycyclic aromatic hydrocarbons (such as naphthalene, benzo(a)pyrene, phenanthrene, and chrysene)(1).
The Del Amo site is located in the city of Los Angeles, California, about five miles east of the Pacific Ocean. Figure 1 (see Appendix A) shows the location of the site, some of its present features, and the surrounding area. The site includes the area with Del Amo Boulevard as its southern boundary, 190th and Knox Streets to the north, and Hamilton and Vermont Avenues to the east. Approximately 700 feet away, Normandie Avenue runs parallel to the site's western boundary. EPA has not yet defined actual site boundaries but refers to the 280-acre area as the Del Amo Study area.
Presently the site serves as an industrial park, with at least 35 commercial businesses, office complexes, and industries, including food processing, light manufacturing, hotel, and warehouse facilities. Ten facilities listed in the August 1990 database for facilities covered under the Resource Conservation and Recovery Act (RCRA)(1) currently operate on parts of the Del Amo site(2). A 100-foot wide Los Angeles Department of Water and Power Right of Way extends across the site approximately 250 feet north of Del Amo Boulevard. A number of petroleum and/or chemical company pipelines also run underground along Normandie Avenue, and Del Amo Boulevard. Two major freeways exist about 500 feet north and east of the site. Residential housing listed as being in the city of Torrance lies immediately south of Del Amo Boulevard across from the site (1,3).
Another site listed on the National Priorities List, Montrose Chemical Company, is located directly west of the Del Amo site along Normandie Avenue. The plant no longer stands on the site, but Montrose formerly manufactured DDT on the premises. Contaminants associated with the Montrose site include DDT, dichlorobenzene, and chlorobenzene. EPA is currently overseeing investigations and clean-up of the Montrose site(4).
Other sites associated with hazardous waste releases to the environment also exist within a one to two mile radius of Del Amo; these include landfills, refineries, and manufacturing facilities. Contaminants found in soil and groundwater associated with some of these sites include trichloroethylene, toluene, benzene, lead, and methyl chloride(3). Some of these sites are presently included in California's list of hazardous waste sites undergoing clean-up under the lead of either the Los Angeles Regional Water Quality Control Board or the California Department of Toxic Substances Control (DTSC)(5).
Built by the United States government to produce synthetic rubber during Word War II, a large industrial facility operated at the site from 1943 until mid- to late 1960s. As shown in Figure 2 (see Appendix A), the facility consisted of three plants: a styrene plant, a butadiene plant, and a synthetic rubber plant. Various companies leased the plants and operated them independently for the government until 1955, when Shell Chemical Company purchased the plants and continued operations. Sometime between 1969 and 1972, Shell closed down the operations. The plants were torn down and the property was sold to land developers in 1973(3). The property has changed ownership several times since 1973 and also has been subdivided for development(2).
Past records regarding the manufacturing operations that occurred at the site provide an indication of some of the materials used and products and waste materials generated. The styrene manufacturing process included ethylene production, ethylbenzene production from ethylene and benzene, and production of styrene from ethylbenzene. Butadiene was manufactured from a petroleum derived butylene mixture. The finished styrene and butadiene were piped to the rubber plant where they were copolymerized with soapy water to make synthetic rubber(1). Records indicate the production capacities of the plants were as follows: rubber - 90,000 long tons per year; styrene - 25,000 short tons per year; butadiene - 30,000 short tons produced per year and 60,000 short tons purified per year(6). (A short ton equals 2,000 pounds, a long ton equals 2,240 pounds). Production rates may have changed over the lifetime of the facility.
An extensive system of underground pipelines existed to transfer raw materials, by-products, products, and possibly waste products. Natural gas, benzene, gas, butadiene, and styrene were the common materials transported to and from the three plants. Some materials, such as benzene, propane, and butylene were transported by pipeline over 15 miles to other related facilities located in nearby cities. A pipeline easement currently still runs across the southern end of the site in between a former waste disposal area and Del Amo Boulevard. Pipelines were known to carry petroleum products, gas, and water. EPA has recently received information about these pipelines and has indicated that several of these pipelines are still active.
Early site maps indicate the presence of numerous storage tanks located either aboveground or underground. However, incomplete records exist to document their previous use and contents and whether they still exist underground or not(2). An underground tank was recently discovered by an existing commercial business on-site during construction. No other information about previous use or contents of the tank is currently available(7).
Existing information about waste disposal practices is incomplete. Records indicate process waste streams from the plants went to separator units within each plant. The effluent from the separator units appeared to have been piped to a central secondary wastewater treatment facility located in the northeast corner of the former butadiene plant prior to discharge to the Knox Street Drain. From there it flowed into a slough, and then emptied into the Dominguez Channel and eventually the Los Angeles Harbor. Solid waste sludge was either transported off-site or placed in waste disposal areas on-site(1). Available information does not indicate use of other on-site waste disposal areas.
Past records, including aerial photographs, show the existence of a 3.7-acre waste disposal area located along the southern part of the site near Del Amo Boulevard (see Figures 1 and 2 (see Appendix A), consisting of 6 unlined pits and 3 unlined evaporation ponds. Approximately 8' deep and with surface areas about 22,000 square feet each, ponds 1A, 1B, and 1C were used from the 1940s until mid-1960s as disposal areas for heavy oil sludge generated in the production of ethylene. Records also indicate the ponds were used for drying aqueous sludges generated from the waste water treatment facilities operating at the plants. Pits 2A through 2F were approximately 20 feet deep and covered a combined surface area of about 11,000 square feet. Aerial photographs indicate the individual pits were "L-shaped," with protrusions extending several feet north. The pits reportedly were used from 1945 to 1955 primarily to hold sulfur tar oil substances resulting from styrene production(6). The waste disposal area was covered with either soil or diking material which originally surrounded the area before Shell sold the property in 1972(1,2).
The waste disposal area exists on what is presently known as Lots 36 and 37 of the Los Angeles County Assessor's Map Number 7351-34 Northwest. DTSC(2) first became aware of hazardous waste contamination in the area in 1981 after Western Waste Industries, Inc. (WWI) requested information about Lot 37. A municipal waste hauler, WWI purchased Lot 37 from Cadillac-Fairview in 1982 and presently uses Lot 37 and additional neighboring lots for its current operations. G.P. Holdings, Inc., currently owns Lot 36(2,8). Since 1982, the DTSC has listed the 3.7-acre waste disposal area in its workplan of hazardous waste sites undergoing investigation and clean-up. Cadillac-Fairview constructed a fence and posted signs in 1983 in order to prevent public contact with the hazardous waste(9).
Between 1982 and 1985, WWI excavated 25' deep on the western end and six feet deep on the eastern end and removed about 10,000 cubic yards of wastes and contaminated soil from waste pond 1A area which was located in lot 37. DTSC authorized the excavation and documented high levels of polycyclic aromatic hydrocarbons, chemicals formed during the incomplete burning of organic substances. WWI encountered many problems during the excavation activities and DTSC documented odor complaints from neighboring residents(9). WWI removed the excavated materials to an approved hazardous waste landfill. Prior to backfilling, deep soil samples taken after excavation detected remaining contamination in the western portion of the lot (800 parts per million (ppm) naphthalene and 50 ppm benzene at 30' to 40' below ground surface). No contaminants were detected below 45'. DTSC believed the remaining contaminants could not be feasibly removed and determined that the remaining levels would not pose a threat to public health and the environment if measures were taken to prevent exposure through direct contact, inhalation, or ingestion(10). According to DTSC records, WWI backfilled the excavated area with clean fill(1).
No excavation of waste ponds 1B and 1C and pits 2A through 2F within Lot 36 has occurred to date. EPA estimates 30,000 cubic yards of waste weighing over 34 million pounds currently exist in the former waste disposal area(1). In 1984, landowners hired Dames and Moore to perform a characterization study for Lot 36. Dames and Moore took soil samples from the waste ponds and pits and installed and sampled three groundwater monitoring wells(6).
In 1985, DTSC signed an agreement with three potentially responsible parties to conduct remedial investigation and feasibility studies to address clean-up options for the known waste area in Lot 36. Woodward-Clyde Consultants contracted to fill data gaps found in the 1984 Dames and Moore study. Their 1987 report provided information from five additional groundwater monitoring wells, a soil gas study, and soil samples taken from areas next to the waste pits(11).
In 1990, under another contract, Dames and Moore completed a final remedial investigation report for the 3.7-acre waste area which only summarized environmental characterization data for soil, groundwater, and air from past studies(12). (Some of these data are presented in the Environmental Contamination Section of this preliminary public health assessment.) A draft feasibility study for the waste area was also prepared presenting soil capping as the preferred method of remediation for the waste area(13). However, DTSC rejected this document. In 1991, Dames and Moore also completed a risk characterization study of the waste area which did not consider off-site human exposure related to groundwater or off-site soil gas pathways(14).
In 1988, EPA initiated activities to gather data for use in preparing a CERCLA Hazard Ranking System scoring package for use in determining whether or not the Del Amo site should be listed on the National Priorities List of hazardous waste sites(15). In July 1991, EPA proposed the 280-acre Del Amo site be listed on the National Priorities List. EPA serves as the lead agency with the State's DTSC providing support. EPA is currently reviewing information available on the 3.7-acre waste area and is developing a workplan for a remedial investigation, feasibility study, and risk assessment to fully characterize the extent of contamination and assess alternatives for clean-up of the entire 280-acre site(3).
On November 7, 1991, Diana Lee and Jane Riggan from the CDHS/ATSDR cooperative agreement project (see Preparers of Report) visited the Del Amo site under the guidance of the site manager from DTSC. We observed the following:
- A six-foot tall cyclone wire fence with barbed wire on top and locked gates on the western and eastern end encloses the pit and pond waste area on the southern end of the site near Del Amo Boulevard. Hazardous waste and no trespassing signs in English and Spanish are posted on the eastern gate and in the middle of the fence along Del Amo Boulevard. (Reportedly, at one time some of the waste area was accessible to children who were seen playing in the area where surface soil contamination likely existed. That condition no longer exists.)
- The waste area inside the inner locked fence appears flat except for a mound about 20 feet high near the east end (Pit 2F area). A few shrubs and weeds mainly cover the surface, but there were some areas with just bare dirt visible instead. A number of 55 gallon drums stood within the fenced waste area.
- An outer locked fence with gates surrounds a larger area extending from Vermont Avenue to Normandie Avenue between Del Amo Boulevard and the Los Angeles Department of Water and Power Right of Way. The fenced waste disposal area is situated in the middle of this larger area. With the exception of the fenced and posted hazardous waste area, the area within the outer locked fence appears to be used by Western Waste Industries to store large metal dumpster type containers. Several large piles of gravel were also standing within the outermost fenced area. Railroad tracks and signs noting refinery pipelines exist west of the inner fenced waste disposal area. No tracks exist within the inner fenced area.
- The outer fence gate along Del Amo Boulevard near Vermont was locked, but an opening existed between the two sides of the gate such that a person could easily slip inside and approach the inner fence surrounding the waste area. Both inner and outer fences also had open areas or gaps between the ground and fence bottom.
- Del Amo Boulevard between Normandie and Vermont Avenues exists mainly as a 30-feet wide, unpaved dirt alley, running between the outer fence and residential backyards. We noticed abandoned cars, and random piles of garbage and refuse along the sides of the alley, and a sewage type odor. We observed people in the alley and several cars, trucks, and motorcycles drove through it.
- Backyards of 25 houses facing 204th Street border the alley. Some of these houses had another residential housing unit in the backyard which is closer to the alley than to 204th Street. The closest residential unit house appeared to be about 100' from the waste pit area. Many yards had abandoned cars or equipment in them. We saw free ranging chickens in some of the front and backyards of houses along 204th Street. A few of the backyards had gardens with vegetables and fruit trees. An empty lot near the alley also had vegetables and fruit growing.
- Power transmission lines extend within the Los Angeles Department of Power and Water right-of-way. North of the right-of-way, a hotel, many office buildings, warehouses, and industrial facilities occupy parts of the site. Most of the site and the surrounding area consist of paved surfaces or building structures. There are two large areas of vacant unpaved land, one along 190th Street and one along Vermont Avenue.
- The area around the site receives a lot of vehicular traffic, with cars, trucks, buses, and motorcycles traveling throughout. Two major freeways, Interstate 405 and 110, exist close to the site.
- The area south of Del Amo Boulevard consists of single family homes and a few condominium complexes. Some of the houses appear to be constructed with raised floors and ventilated crawl spaces beneath the floors while others appeared to have been built on concrete slab foundations.
On January 21, 1991, Diana Lee and Jane Riggan visited the site and surrounding areas again. We noticed conditions in the Del Amo Boulevard alley were much worse than during our earlier visit. The dirt road had many ruts, making car driving more difficult, and there were more piles of garbage and abandoned materials as well as a strong sewage odor. People were walking and/or driving through the alley.
A residential community lies south of the site across from Del Amo Boulevard. About 26,000 people live within a one mile radius of the site. Included in that figure are the 15,000 people estimated by the 1990 census information who live in 3,200 housing units one mile south of the site. Seventy-three percent (73%) of this population are 18 years of age or older. The format of the 1990 census information we reviewed does not allow for further breakdown of housing units or age-specific information. The census data show the racial/ethnic breakdown as follows: 38% Hispanic; 38% White; 17% Asian/Pacific Islander, 6% Black; 0.5% American Indian, Eskimo, Aleut; and 0.5% other race.
Prior to the 1930s, land use in the Del Amo site area was mainly agricultural. Beginning in the 1940s, industry and residential areas started to develop in the area. Currently the site is zoned for light industrial use and many commercial businesses, industry, and warehouse facilities exist on the site and surrounding areas.
As mentioned previously, a power right-of-way with a high power transmission lines lies about 200' north of the southern boundary of the site (Del Amo Boulevard). A petroleum pipeline easement also lies along the site's southern boundary. A residential community with single family homes, condominiums, and apartment complexes exists mainly south of the site(2,12). About 25 houses border Del Amo Boulevard, across from the waste pit area.
Although some residents appeared to be growing fruits and vegetables in their yards, no major agricultural activity occurs within a two mile radius of the site. The area around the site does not support abundant wildlife nor hunting(12).
The site and surrounding areas have a Mediterranean-type climate with mainly warm, dry weather. Average annual rainfall in the area is 12 to 16 inches. Rain usually falls in the winter, but lower rainfall than normal has been reported for the area as well as the entire state for the last three to five years due to drought conditions(12). Information about prevailing wind directions in the Del Amo site vicinity comes from reports prepared for the nearby Montrose Chemical Company Superfund site. Generally, the prevailing daytime winds come from the west, but lighter prevailing night and early morning winds are from the east and northeast. Following winter storms, strong winds often prevail from the west and north. During fall, winter, and spring, dry and gusty winds, locally known as the Santa Ana winds, sometimes blow in a northeasterly direction from the interior towards the coast(4).
No surface water bodies currently exist on the site. Storm sewer systems catch surface water runoff in the area and connect with concrete-lined drainage and flood control channels which empty into the Dominiguez Water Basin about two miles east(1). During the time the rubber manufacturing facilities were in operation, effluent from waste treatment systems was piped into an open ditch at the northeast corner of the site (now Vermont Avenue and Knox Street) and then discharged into a flood control channel located about half a mile east of the site(1,2).
No known drinking water wells exist on the site. Seven municipal drinking water wells are located within approximately four miles of the site, with the closest one located less than two miles southeast(1). Three of these wells lie southeast of the site, three to the southwest, and one to the north. Drinking water supplied to the area consists of a blend of mainly surface water and some groundwater. The surface water is transported from the Colorado River in Arizona and the Sierra Nevada Mountains in northern California. The groundwater comes from a deep underlying aquifer (water bearing unit) named the Silverado aquifer.
To obtain information about groundwater units underlying the Del Amo site, we reviewed information gathered for the neighboring Montrose site(4). Located within the West Coast Groundwater Basin, the water bearing zones underneath the site appear to consist mainly of alternating, discontinuous layers of gravels, sands, silts, and clays. The sand and gravel form the major water bearing units (aquifers), and the silt and clay act as confining layers (aquitards) to restrict movement between the aquifers. Several aquifers and aquitards exist beneath the Del Amo site. From ground surface downward, these include: 1) the Bellflower aquitard, 2) the Gage aquifer, 3) an unnamed aquitard, 4) the Lynwood aquifer, 5) an unnamed aquitard, and 6) the Silverado aquifer. Because the unnamed aquitards are not consistently found across the basin, the Gage, Lynwood and Silverado aquifers are described as a single hydraulic unit within two miles of the Del Amo site(1,15).
The Bellflower aquitard exists at a depth of about 60' below ground surface (bgs). It appears to be about 80' thick in the area of the site(1). In most areas of the West Coast Basin, the Bellflower aquitard consists mainly of clay and silty clay. However, available information for the area around Del Amo indicates the Bellflower aquitard is composed of more permeable layers of sand, silt, and clay. Apparently groundwater in the Bellflower aquitard is present under unconfined conditions(12).
The Gage aquifer lies directly beneath the Bellflower aquitard. About 160' thick, it exists about 140' bgs near the site(12). Monitoring wells are screened and samples taken from both the Bellflower aquitard and the Gage aquifer(1). Historically, wells screened in the Gage aquifer supplied water for irrigation and domestic purposes(4).
An unnamed aquitard generally separates the Gage aquifer from the underlying Lynwood aquifer except in a few areas near the site where it appears the aquitard pinches out and the Gage and Lynwood merge at a location about two miles southwest of the site. The top of the Lynwood aquifer is at a depth of about 300' bgs at a location 2,000' southeast of the site. It measures 200' thick approximately 3.5 miles southwest of the site(1).
Beneath the Del Amo site, the Lynwood aquifer appears to be separated from the Silverado aquifer by an aquitard about 100' thick. One to two miles west of the site, the two aquifers merge to form a single hydraulic unit. Most water supply wells screened in the Lynwood aquifer are also screened in the Silverado aquifer. A major source of groundwater in the West Coast Basin, the Silverado aquifer measures about 300' thick and exists about 500' bgs in the area of the site(1).
Regionally, the groundwater is mainly replenished by injecting fresh water into a line of injection wells that exist along the coastline. These injections serve to form a freshwater pressure ridge that acts as a barrier to protect basin groundwater from saltwater intrusion. The injections also promote regional groundwater to flow towards the east(4). On-site monitoring wells screened in both the Bellflower aquitard and the Gage aquifer indicate that shallow groundwater beneath the site flows to the east-southeast. Measurements collected from Los Angeles County observation wells indicate that groundwater near the site in the deeper Lynwood and Silverado aquifers also flows towards the east-southeast(1).
Well boring logs show that, to a depth of about 100 feet below the Del Amo site, subsurface deposits consist mainly of layers of clay silts, gravel, and sandy sediments. Layers of shells and shell fragments were also found(12).
Sources of existing health related data in California that may be useful in evaluating hazards from environmental exposure include the California Birth Defects Monitoring Program, the California Cancer Surveillance Program, and vital statistics records. The California Birth Defects Monitoring Program first began collecting data for Los Angeles County in 1990(16). Established in 1970, the Cancer Surveillance Program for Los Angeles County (Region 9 of the California Tumor Registry) serves as the population-based cancer registry for Los Angeles County where the Del Amo site exists(17).
In response to concern voiced by local residents that they were experiencing certain health problems resulting from chemicals associated with the Del Amo and Montrose hazardous waste sites, CDHS conducted an epidemiological investigation in the communities near the two neighboring sites between 1984 and 1987. CDHS released the results of this study in 1988(18). CDHS also completed a report examining health outcomes from vital statistics records for the period between 1970 and 1984(19). Researchers from the University of Southern California also reviewed cancer cases reported to the California Tumor Registry from census tracts surrounding the site(20). The findings from these studies and other relevant health data bases will be discussed further in the Health Outcome Data Evaluation section of this preliminary public health assessment.
The community first became aware of the Del Amo site in 1983 when a reporter from the Los Angeles Times interviewed residents about living next to a hazardous waste site. Within a month some residents formed the South Bay Chemical Alert Network (SBCAN) and identified their key health concerns as the effects of air emissions released during the excavation activities for waste pond 1A, potential groundwater contamination, and the effect of contaminated soil remaining on-site after the excavation(21). In response to their concerns, DTSC arranged for soil samples from residential backyards and tap water from several homes to be tested and air monitoring data to be collected (see Environmental Contamination section). Community members carried out their own informal neighborhood survey and reported experiencing skin rashes, numbness of feet and hands, respiratory problems, cancers of various sites, prolonged colds, miscarriages, birth defects, stomach aches, and headaches(22).
As mentioned previously, the Epidemiological Studies and Surveillance Section within CDHS carried out a health study from 1984 to 1987 in response to the community concerns. Health effects detected during the study included those often associated with airborne pollutants, such as skin irritation/rashes and irritation of the eyes, upper respiratory tract, and throat. Other noted symptoms included earaches, dizziness, and fatigue. The study reported that some symptoms, such as headaches, sore throats, and sinus congestion, occurred more often in people who detected odors in their neighborhoods(18). Additional details about the study are provided in the Health Outcome Data Evaluation section.
During part of the time the study was being carried out, the Del Amo Advisory Committee formed and met eight times between 1983 and 1985. Membership on the committee consisted of representatives from the agencies, the potentially responsible parties, the L.A. City Attorney's office, and SBCAN. Despite the existence of the Advisory Committee, SBCAN was still frustrated about the community's access to information and their role in the decision-making process regarding site clean-up. They invited Los Angeles Mayor Tom Bradley to visit the site on November 4, 1984, and to meet with concerned community leaders.
In overseeing earlier investigations of the 3.7-acre waste disposal area, DTSC issued several fact sheets to the community. Released in 1986, the first fact sheet on Del Amo gave a status report on DTSC activities and plans for cleanup of the site(23). This fact sheet explained that previous studies had not identified the extent of soil and groundwater contamination and that additional work would be necessary to develop a remedial action plan. Another fact sheet released in July 1990 announced that the remedial investigation report for the waste disposal area had been completed and contained data on soil and groundwater sampling and results of on-site soil gas studies to determine whether contaminated soil gas was migrating through the soil or into the air(24). The fact sheet also reported on DTSC's plan to conduct an off-site soil gas study to determine whether contaminants could be moving off-site through gases in the soil. The off-site soil gas study, conducted in March-April of 1991, was prompted by neighborhood complaints received in 1989 about odors after rains(7).
Based on a review of available site literature, it is difficult to trace what became of the Del Amo Advisory Committee after 1985. However, a neighborhood group called the Del Amo Citizen's group had meetings in 1988 and 1989. These meetings were held in homes of residents and allowed DTSC to update the community about site activities. The last meeting, which occurred in April 1989, was poorly attended and the DTSC felt that this was an indication that the residents who had been most concerned in the early years no longer lived in the neighborhood(7).
Because the lack of recent community input made it difficult to assess the extent of health concerns, CDHS/ATSDR staff walked around the area between Del Amo Boulevard, Normandie Avenue, Vermont Avenue, and Torrance Boulevard and talked with some of the residents on January 21, 1991. We arranged for a Spanish speaking DTSC staff person to assist us with speaking to Hispanic residents. We spoke with people from ten households. The majority of the households complained about unpleasant odors mainly described as gas/burned oil/chemical smells. The health concerns were fairly consistent with those found in the 1984 Del Amo/ Montrose Health Effects Study(18). The three predominant complaints reported in January 1991 were: 1) rashes and skin irritations; 2) chronic lung problems, including asthma, allergies, trouble breathing, bronchitis; and 3) headaches. Several respondents said that they had problems with nausea. One family was told by their doctor that their nine year old child who has severe allergies should not remain in the neighborhood.
Seven of the households reported that they had difficulty growing fruits and/or vegetables. Typical complaints were that they would not grow at all, that they were very small and sometimes cracked open, that they had unusual color, and that they did not taste good. Another woman said that twelve of her fifteen chickens had died and all the baby chicks died. She said that she had cemented over a large part of the backyard because of concern about the soil quality.
There was also concern expressed about the quality of the drinking water. Several people volunteered that they were using bottled water. Some people commented about the "men in white suits" who came to test the monitoring wells and stated they saw it as a clear indication that the water that they were drinking was unsafe. One woman reported that during the 1960s she would have nausea, vomiting, and green stools if she drank the water. Following is a listing of the concerns that were gathered during the community interviews:
- If there are unpleasant odors outside, does that mean that the air is unhealthy to breathe?
- Are rashes, breathing problems and headaches caused by chemicals from the site?
- If there is trouble growing fruits and vegetables and if they don't taste right, are they safe to eat?
- Is the water safe to drink?
- Is the soil safe and can my children play in the backyard?
- Is it safe to live in this neighborhood?
1. The Resource Conservation and Recovery Act (RCRA) is a federal law which created the hazardous waste management program, a regulatory system which tracks hazardous waste from time of generation to disposal.
2. Prior to July 19, 1991, the Department of Toxic Substances Control Program (DTSC) was known as the Toxic Substances Control Program within the Department of Health Services. Under a reorganization, DTSC is now part of the California Environmental Protection Agency (CAL EPA).