PRELIMINARY PUBLIC HEALTH ASSESSMENT
SOUTH GATE, LOS ANGELES COUNTY, CALIFORNIA
This section presents contaminants identified for further evaluation or follow-up. Selecting these contaminants does not necessarily mean that a health threat exists. We evaluate these contaminants in the subsequent sections of the preliminary public health assessment and determine whether exposure to them has public health significance. CDHS and ATSDR select and discuss these contaminants based upon the following factors:
- concentrations of contaminants on and off the site;
- field data quality, laboratory data quality, and sample design;
- comparison of on-site and off-site concentrations with health assessment comparison values for noncarcinogenic and carcinogenic endpoints; and
- health concerns expressed by the community.
The data tables included within the On-site and Off-Site Contamination subsections present the maximum concentration of each contaminant detected for comparison with existing health guidance values. Contaminants exceeding these values, or for which no value is available, are selected for further evaluation. When selected as a contaminant of concern in one medium, that contaminant will be reported in all media. The tables in this section include the following acronyms:
- CREG Cancer Risk Evaluation Guide
- EMEG Environmental Media Evaluation Guide
- RMEG Reference Dose Media Evaluation Guide
- LTHA Lifetime Drinking Water Health Advisory
- TLV Threshold Limit Value established for airborne contaminants
- ppm parts per million (equivalent to milligrams per kilogram [mg/kg]; a milligram is one thousandth of a gram)
- ppb parts per billion (equivalent to micrograms per kilogram [ug/kg]; a microgram is one millionth of a gram)
Health guidance values used to select contaminants for further evaluation include Environmental Media Evaluation Guides (EMEGs), Cancer Risk Evaluation Guides (CREGs), Reference Dose Media Evaluation Guide (RMEGs), and other relevant guidelines. EMEGs are media-specific values developed by ATSDR to serve as an aid in selecting environmental contaminants of concern that need to be further evaluated for potential health impacts. EMEGs do not consider carcinogenic effects and are derived from ATSDR's Minimal Risk Levels (MRLs). RMEGs also consider noncancer health effects, but are derived using EPA's Reference Dose (RfD). Both MRLs and RfDs are estimates of daily exposure to a chemical considered unlikely to cause noncancer adverse health effects.
CREGs are estimated contaminant concentrations which theoretically could cause one excess cancer in a million persons exposed over a lifetime. CREGs are calculated from EPA's cancer slope factors.
EPA's Lifetime Drinking Water Health Advisory (LTHA) defines a concentration in drinking water at which noncancer adverse health effects would not be expected to occur. LTHAs are not regulatory standards and do not reflect economic and technological feasibility; they are based solely on health considerations.
Threshold Limit Values (TLVs) define an eight-hour average concentration to which nearly all workers may be repeatedly exposed day after day without adverse ill effects. TLVs are guidelines published and updated annually by the American Conference of Governmental Hygienists. TLVs are not regulatory standards.
The Toxic Chemical Release Inventory (TRI) contains information on estimated annual releases of toxic chemicals to the environment (via air, water, soil, or underground injection) which is voluntarily reported by companies to EPA. TRI data can be used to give a general idea of current environmental emissions occurring at or near a site. TRI data may also be used to determine whether the on-going emissions from reporting facilities may be contributing an additional exposure to the nearby population.
We conducted a search of the EPA TRI for the site and local area (zip code 90280, including the city of South Gate) for the years 1987, 1988, 1989, and 1990 (the years for which TRI data were available). No information about the Cooper Drum site appeared on TRI. Of the nine manufacturing facilities located within a two-block radius of the site, only one company, Purex (Dial) Corporation, reported releases to air of chlorine (1987 and 1988), sulfuric acid (1987, 1989, and 1990), and an ammonia release in 1988 only.
During the years 1987 through 1990, 12 to 14 companies each year reported releases totalling between 191,735 and 259,520 pounds of between 14 and 25 different chemicals into air. Some of the compounds listed as being released into air included organic chemicals such as PCE, trichloroethane (TCA), methylene chloride, methyl ethyl ketone (MEK), toluene, and xylene, as well as heavy metals such as nickel and chromium.
Soil - Surface
No monitoring data are available for surface soil. In August 1984, Los Angeles County Health Department (LACHD) cited Cooper Drum for discharge to the ground surface, noting that the asphalt surface was degraded, and spillage and drippage of drums were occurring onto the surface areas of the plant. By late 1986, Cooper Drum had repaved the entire site, after removing about 180 tons of contaminated soil and asphalt (24).
Soil - Subsurface
Table 1 lists the maximum levels found for organic chemicals which appeared in onsite subsurface soil. All maximum values were found in the 1989 Geotech study. Levels of each contaminant are compared with health comparison values. Of the contaminants listed, bis (2-chloroethyl) ether, 1,1-dichloroethylene, and PCE were at levels above comparison values. No comparison value exists for 1,1,1-trichloroethane (TCA). Total petroleum hydrocarbons were found at high levels; however, no comparison value exists for them. Benzene, chlorobenzene, methylene chloride, toluene, and trichloroethylene (TCE) were found at levels below comparison values. The other contaminants were not detected in onsite soil, but were found in offsite soil or groundwater.
Looking at the site as a whole, PCE was found at its highest level of 1,536 ppm in the 0-1 foot bgs sample taken next to the caustic flushers in the main process area. It was also found in a total of 14 out of the 18 samples taken at the site, including the hard wash area, the main process area, the two tank groups, and the east rain clarifier.
In November 1984, Cooper's consultant Conservtech sampled soil to determine the level of contamination at the site (2, 11). This was in response to the violation given by LACHD in August 1984. Samples were analyzed for metals, polychlorinated biphenyls (PCBs), chlorinated pesticides, and organic chemicals. PCBs at 31.3 ppm, zinc at 2,494 ppm, total chromium at 30 ppm, and various other heavy metals were found under the hard wash area. Highest levels of lead at 163 ppm and copper at 84.3 ppm were found north of the main process area. The laboratory recommended further testing to establish whether the chromium found was hexavalent, but no records are available to show that this was done. No pesticides were found. Two composite samples were also analyzed for volatile organics. PCE contamination at 57 ppm, toluene at 43 ppm, xylene at 160 ppm, and phthalates and naphthalene at 32.8 ppm were found beneath the hard wash area at 12 inches bgs. No volatile organics were found in the yard north of the main process area.
Based on the sample results, LACHD required Cooper to remove all contaminated soils. Approximately 180 tons of contaminated soil and asphalt were removed from the site during 1985 and 1986. The areas from which contaminated soil was taken were backfilled with clean fill and repaved. There is no documentation showing that samples were collected to verify that the soil was free of contamination prior to the backfilling action. In fact, because the yard north of the main process area was only excavated 1/2 inch, and various heavy metals had been found beneath it at 6 and 12 inches bgs, heavy metals probably were allowed to remain under this area of the site (2, 24).
In April 1987, as part of an emergency response concerning a discharge of sodium hydroxide wash water from Cooper's main process area onto the adjacent Tweedy Elementary School property, four corings were made through the vertical wall of the Cooper facility foundation by LACHD. The soil beneath the main process area was shown to be saturated with caustic fluid with a pH of 14 (11). No records exist of further analysis on these samples.
In June 1989, Geotechnical Consultants (Geotech) completed a Site Investigation based on sampling done in February 1989 of the Cooper property for DTSC and LACHD (10). Results for this sampling event are shown in Table 1. The investigation consisted of drilling and sampling at 20 on-site locations. The boring depths ranged from 3 to 61 feet bgs. The borings were clustered around the various process and tank areas on site. Analytical results presented in the report show on-site soil contamination to depths of 20 feet by a variety of organic compounds. Metals were not analyzed because they were found at low levels, and the major purpose of the investigation was to investigate the correlation between subsurface soil and groundwater contamination by organics. Two background borings were sampled at 20 feet bgs, one upgradient and the other downgradient to the site. See Figure 3 for all boring locations. The upgradient boring showed contamination by acetone, MEK, methylene chloride, and PCE. The downgradient boring showed acetone and MEK contamination (10). These results were not above health comparison values, and are, thus, not included in Table 1.
As shown in Figure 3, the June 1989 boring locations were in three main areas: the hard wash area in the northeast portion of the site, the main process area along the south border of the site, and the tank groups area just north of the process area (11).
Main process area: In the June 1989 Geotech survey, seven borings were made under the main process area, of which only P1 and P3 went down to 20 feet bgs and the other five went down to only 1 foot bgs because of the foundry slag and scrap metal that had been used to backfill this area. The main process area was found to contain eight of the eleven maximum concentrations of chemicals listed in Table 1. P1, located next to the caustic wash line, contained the highest site levels for PCE at 1,500 ppm, TCE at 36.4 ppm, and TCA at 18.0 ppm, all found at 0 to 1 foot bgs. The wide range of organics and elevated pH values showed a conclusive relationship between the April 1987 leak onto Tweedy School property and contamination beneath the main process area. A southerly migration of contamination in the subsurface soil was documented. The fact that P1 and P3 showed no free liquids indicated that the hard piping installed after the April 1987 incident had eliminated the source of leakage.
Tank groups area and east rain clarifier: Geotech monitored seven boreholes at the two tank groups located parallel to the north side of the main process area. These tanks and clarifiers were used to receive caustic material, remove waste solids, and then recirculate the process fluids. The tanks had previously been single-lined concrete, but were retrofitted with steel liners to provide dual containment by April 1989, in response to the April 1987 leak. The monitoring results showed clear past tank leakage by the four tanks on the east end (tank group 2), by holding tank #1 on the west end, and possibly by one or more of tank #1's adjacent clarifiers. Lateral migration was limited, and the vertical extent of migration was not defined.
The one borehole at the east rain clarifier did not contain detectable levels at 5 and 15 feet bgs but did contain PCE 10 feet bgs. These findings indicated that no leakage had occurred from this clarifier, but either lateral migration from the April 1987 leak, or a more extensive, area-wide background condition existed.
Hard wash area: Four borehole samples taken in the hard wash area showed tank leakage by the four interconnected sludge tanks. Organics were found down to 20 feet bgs, but no further, even though BH3 was tested down to 40 feet bgs. BH1, northwest of the hard wash area showed organics at 20 feet bgs but not above, indicating lateral migration from the tank area. Among the organics, PCE at 2.32 ppm was found at 20 feet bgs.
In August 1990, Geotech conducted a groundwater investigation, consisting of installing and sampling three monitoring wells, at Cooper (25). Monitoring Well 1 (MW1) is located northeast of clarifier #2 in the tank groups area just north of the main process area, Monitoring Well 2 (MW2) is located south of Sludge Pit #1 in the hard wash area, and the background well (MW3) is located 130 feet north (upgradient) of the site. Soil taken from the two onsite well borings was sampled for volatile organics, with samples taken at five or six intervals from a depth of 6 to 59 feet bgs. The soil from MW1 did not contain detectable levels of contamination at any levels sampled except for 5 ppb TCE and 17 ppb 1,1-dichloroethylene (DCE), both at 14 feet bgs. The soil from MW2 contained 14 volatile organic compounds. Five of these contaminants were also found in the groundwater monitoring well samples, as described in the Monitoring Wells section. Those contaminants are PCE, TCE, 1,1-dichloroethane, 1,2-dichloroethane, and benzene (25).
A comparison of the 1989 samples to 1990 MW1 and MW2 soil samples, taken at the same locations, gives an indication of the movement of volatiles through the soil (10, 25). In 1989, soil samples taken near MW1 showed ppm levels of acetone, MEK, PCE, and methylene chloride fairly equally distributed at 5, 10, 15, 20, and 40 feet bgs. By 1990 these contaminants had migrated vertically such that none were detected in the subsurface soil sampling of MW1. In 1989, soil samples taken near MW2 showed volatile organics present between 5 and 20 feet bgs, with none detectable at 40 feet bgs. In contrast, the 1990 MW2 sample showed volatile organics primarily between 28 and 53 feet bgs, except for acetone and MEK, which were found only at 8 feet bgs. Again a vertical migration appears to have occurred.
Table 2 shows the results for onsite groundwater monitoring. Contaminants shown to be above comparison values included benzene, 1,2-dichloroethane (DCA), 1,1-DCE, cis- 1,2-DCE, PCE, and TCE. Geotech installed three monitoring wells in August 1990, and took samples in October 1990, in order to characterize the contamination at the Cooper site (25). Groundwater was first encountered at 53 feet bgs in MW1, near the base of the Bellflower aquiclude, transitional to the underlying Exposition aquifer. Analysis of water from MW1 indicated detectable amounts of contaminants were not present in the water. Analysis of water from MW2, located south of the hard wash area, showed measurable amounts of twelve volatile organic compounds, the highest being TCE (178 ppb) and cis-1,2-DCE (207 ppb). Analysis of water from MW3, the background sample located 130 feet north of the site, showed detectable levels of TCE (8 ppb), trans-1,2-DCE (0.9 ppb), and cis-1,2-DCE (3 ppb).
Geotech concluded from these results that contamination had migrated to the underlying shallow aquifer under the hard wash area and that groundwater remediation was needed. However, the amount of downgradient migration was not yet defined. Geotech recommended that a fourth monitoring well downgradient to MW2 near the maintenance shop be installed and that a second set of water quality samples be taken from all four wells. Geotech also recommended that a slow purge be used to reduce total suspended solids in the water samples. To date, this fourth monitoring well has not been drilled nor have follow-up samples been taken.
No records of onsite ambient air sampling are available. However, numerous complaints of odor emanating from the site have been documented. These complaints are discussed in the Offsite Contaminants section.
The four principal potential air contamination sources include the following: 1) uncovered tanks, sumps, and pits; 2) the paint spraying booth; 3) drum cleaning and refurbishing area; and 4) the areas of soil contamination. Each of these sources is discussed below.
- Uncovered tanks, sumps and pits
- the paint spraying booth
- Drum cleaning and refurbishing area
- Areas of soil contamination
Our site visit in October 1992 revealed that most of the previously open pits and sumps in the hard wash area have been covered with cement slabs since the Waymire Drum Company began operations on the premises in June 1992. The open pits surrounding the hard wash area are not in present use by Waymire staff; they have been cleaned out, are regularly inspected, and a rain roof is being built to keep out the rain. All of the aboveground tanks in the main process area appeared to be covered.
In August 1984, Los Angeles County Health Department (LACHD) and Los Angeles Water Quality Control Board did a joint inspection of Cooper. A recommendation was made that workers wear organic vapor respirators in the spray booth, and that the ventilation of the painting area be increased (5).
In April 1985, responding to a complaint from neighboring Tweedy School, Cooper installed a scrubber to reduce emissions from the paint spray booth and a caustic exhaust stack. A total of three exhaust stacks then existed from the main process area, including a paint booth stack, an acid (hydrogen chloride) stack, and a caustic (sodium hydroxide) stack. In 1986, SCAQMD did several emission surveys of these stacks, finding emissions levels well below the agency's limits (27, 28, 29). However, one SCAQMD air quality chemist's review found potential emission problems because of drums were allowed to dry outside of the spray booth and because a high potential existed for aerosol formation and fugitive emission from the caustic drum wash line (30).
The major hazardous chemicals used by Cooper for processing approximately 26,000, 55-gallon drums per month in 1987 included sodium hydroxide, hydrogen chloride, and paint constituents. Paint constituents included lead, lead chromate, and a variety of solvents including alcohols, MEK, and aromatic hydrocarbons (31). In addition, incoming drums for recycling may have contained a wide variety of heavy metals, pesticides, PCBs, waste oils, and solvents, as evidenced by soil contamination.
During our site visit of October 1992, the sodium hydroxide mist heated to 140 degrees F was visible and gave off a noticeable irritating odor, despite the local exhaust ventilation system. The other major contaminant in this area is the hydrochloric acid wash.
Workers were not wearing respiratory protection. No worker monitoring reports are available for this area.
The entire site was paved in 1986, thereby reducing or eliminating the possibility of air contamination from volatilized compounds in soil unless a soil excavation is carried out in the future.
Soil - Surface
In December 1986, LAUSD and LACHD responded to complaints of damp soil and odors in the planter area adjacent to Cooper. The planter area was an unpaved strip centered along the Cooper border of Tweedy School and measured about 2 feet wide by 40 feet long (2). Preliminary observation revealed damp soil with an apparent hydrocarbon odor. Soil samples were taken by LAUSD and LACHD. The single sample taken by LAUSD was found to contain 90,000 ppm total hydrocarbons, but was not further analyzed for specific components. Based on this result, LACHD issued a notice to Cooper to submit a site assessment by March 13, 1987. An assessment plan was not submitted by this date (32, 33). Cooper did remove the top layer of soil to eliminate potential public contact, according to a LACHD report (6).
Soil - Subsurface
Table 3 shows the maximum concentrations of organic chemicals found in offsite subsurface soil. All values were taken from the June 1987 Conservtech sampling event (31). These samples contained a total of 13 different organic chemicals, with maximum concentrations found in borehole 7 at 10 and 14 feet bgs (see Figure 3). Contaminants found at levels above comparison values included 1,1-dichloroethane and PCE. No health comparison values exist for TCA or total petroleum hydrocarbons, so these may also be considered contaminants of concern. Total petroleum hydrocarbons (TPH) were found at a maximum of 2,800 ppm in seven of the samples, with the highest level found in borehole #7. The samples with high TPH levels also showed high levels of organics. The three background samples taken showed small amounts of the same contaminants found in the study area, including PCE, toluene, TCA, and TCE.
As mentioned previously, in April 1987, four corings were made through the foundation of the Cooper facility by LACHD. This was part of the emergency response concerning a discharge of liquid onto the north border of the Tweedy School yard. Analyses indicated that the soil beneath the concrete foundation of the process area was saturated with caustic fluid with a pH of 14 (34).
In June 1987, in response to a directive by the LACHD, Conservtech drilled 13 boreholes in the areas of the Tweedy schoolyard found to have the highest pH values (31). (See Figure 3 for sample locations and Table 3 for selected sampling results.) An additional three boreholes were drilled as background samples near the west, south, and east borders of the schoolyard. The pH values were between 8.3 and 12.6 in the suspect area, and between 8.07 and 9.34 in the background samples. According to its survey report, Conservtech did not sample below 25 and 30 feet bgs due to the high clay content and marked decrease in pH values.
Groundwater - Monitoring Wells
In July 1987, Conservtech installed a monitoring well, converted from borehole #8, in the area of highest soil contamination at Tweedy School (31). Although called a monitoring well, it does not extend to the underlying Exposition aquifer (60 to 80 feet bgs); it extends only from ground surface to 20 feet bgs, with perforated pipe installed in the final 10 feet. The well was inspected on July 15, July 28, August 18, and September 8, 1987. The four inspections indicated no evidence of liquid seepage into the well, and pH at the bottom of the well measured between 7.5 and 8.0, close to that of drinking water in the area.
This monitoring well was analyzed for soil vapors, including explosive vapors and gases, using a portable hydrocarbon monitor (calibrated to butane). Levels were measured above 500 ppm at 15 feet bgs, 75 to 250 ppm at 10 feet bgs, and 10 or less ppm at 5 feet bgs. In addition, by laboratory analysis, vapor samples taken at 15 feet bgs and analyzed for purgeable organics showed levels of 5.1 ppm chloroform, 6.7 ppm TCA, and 13.1 ppm 1,1-DCA. Thus, there is potential for the presence of these contaminants in groundwater. In fact, 1,1-DCA was also found in on-site groundwater monitoring wells. (See Table 2.)
No monitoring wells were drilled down to the shallow Exposition aquifer layer beneath the Tweedy School site, apparently due to Conservtech's determination that the clay/silt layer at 23 feet bgs would be impermeable to vertical contaminant migration. However, no monitoring well has been installed to confirm that theory.
As mentioned previously, another offsite background monitoring well was installed by Geotech in August 1990 at a location 130 feet north and upgradient of Cooper's north central border. A sample taken in October 1990 showed detectable levels of TCE, trans-1,2-DCE, and cis-1,2-DCE. (See Table 2.)
Groundwater - Public Supplies
Table 4 shows maximum concentrations of contaminants in well water samples taken between 1986 and 1992 (11, 35). (See Figure 2 for well locations.) As the table indicates, a trend of increased PCE values downgradient to Cooper exists. However, some PCE contamination is found upgradient (well #7) and cross-gradient (well #22B) to the site as well. Based on these findings, the Listing Site Inspection report stated that an historical observed release to groundwater had been documented at Cooper. It was added, however, that conclusive attribution of the South Gate PCE plume solely to Cooper was unlikely since other industries in the area had used industrial solvents in the past as well (11).
In December 1986 the city of South Gate closed four of its municipal wells because of PCE contamination. These four wells (#13, #14, #18, and #19) are located in the South Gate Recreation Park, within 2,000 feet directly downgradient of Cooper and are perforated in the Silverado aquifer at 600 feet bgs. No previous testing had been done for volatile organics in municipal wells in South Gate. In 1991, further testing caused South Gate to close three more wells, including #8 (downgradient), #7 (upgradient), and #22B (cross-gradient).
The Listing Site Inspection stated that a link between subsurface soil contamination at Cooper and contamination of the Silverado aquifer at 550 to 600 feet bgs, from which South Gate draws its drinking water, existed. A discussion of how the shallow Exposition aquifer at 80 feet bgs is interconnected with the much deeper Silverado aquifer is found in the Natural Resource Use and Features section.
Table 5 shows the maximum contaminant of concern concentrations found in air on the Tweedy School grounds. Based on 8-hour samples taken by SCAQMD, carbon tetrachloride, PCE, and TCE are above comparison values. Based on a single 2-hour sample taken by LAUSD, chloroform, methylene chloride, and toluene are above comparison values. No comparison value exists for hydrogen chloride; however, it was found at a level above the recommended workplace limit. The average background levels were also above comparison values for carbon tetrachloride, chloroform, and TCE, indicating a region-wide air pollution problem.
In July 1986, on five separate days, SCAQMD took 8-hour and 24-hour time weighted average samples for 14 solvents, chosen because of their appearance on the LACHD area industry survey done after the chlorine release in February 1986 (8). Results for the 8-hour samples are listed under the heading "SCAQMD" in Table 5. The July 1986 results were studied by LACHD Toxics Epidemiology Program, and its findings are discussed in the Health Outcome Data Evaluation section.
LAUSD did short-term sampling on October 23 and 28, and December 2, 1986 (36). A single 2-hour sample on October 23, 1986, was analyzed for hydrocarbons. As seen in Table 5, toluene, xylenes, chloroform, TCA, TCE, MEK, and acetone were found at levels many times higher than the LAAQMD results. This sample appears to indicate that short-term exposures may have existed at much higher levels than 8-hour averages indicated. Unfortunately, only this single sample was taken for short-term solvent exposure.
On October 28, and December 2, 1986, LAUSD took one 2-hour and two 3-hour samples for sodium hydroxide (36). The laboratory analysis found acid, hydrogen chloride, rather base material, with acid levels at 1.38 ppm, 4.67 ppm, and 6.0 ppm, respectively. These results are extremely high, given that the recommended limit for occupational exposure to hydrogen chloride is a ceiling limit (i.e., exposure concentration may not exceed this level at any time) of 5.0 ppm. Again, more sampling would have been useful. However, a short- term hydrogen chloride exposure potential to Tweedy staff and students was documented by these three samples.
In 1992, computer-generated air modelling was done by LAUSD, showing the contours of air plumes for hydrogen chloride, sodium hydroxide, and paint booth VOCs coming from the three emission stacks in the Cooper main process area. These models used stack parameters and emission data from 1986. The models concurred with the high hydrogen chloride sampling results found in 1986 in the northeast quadrant of Tweedy playground (37).
In August 1987, Conservtech used a portable hydrocarbon monitor, calibrated to butane, to measure tree planters adjacent to boreholes #7 and #8, where highest levels of subsurface organics had been found (11). (See Figure 3 for locations.) At that time the planter boxes had not been paved over. Zero hydrocarbon vapor readings (detectable to 5 ppm of butane gas) were observed on the monitor. Although Conservtech determined from these readings that there was no evidence of hydrocarbon vapors having adverse effects to the general public or children, the portable meter used had a very high detection limit (5 ppm) and no ability to identify specific compounds. Therefore, this conclusion is not substantiated (31).
We reviewed the Data Quality Assurance Review for the Hazard Ranking System Documentation and the Data Quality Assurance/Quality Control (QA/QC) summary for groundwater and soil data collected by Conservtech and Geotech. No analytical problems were noted. As noted in the Off-site Ambient Air section, Conservtech portable hydrocarbon monitoring of vapors from soil was not sufficient to determine that there was no hazard because the limit of detection of the instrument was very high (5 ppm) and the instrument used had no ability to identify specific contaminants other than total hydrocarbons.
In preparing this preliminary public health assessment, CDHS and ATSDR rely on the information provided in the referenced documents and assume that adequate data quality assurance and quality control measures were followed with regard to chain-of-custody, laboratory procedures, and data reporting. The validity of the analysis and conclusions drawn for this public health assessment are determined by the completeness and reliability of the referenced information.
During our site visit of October 1992, the Cooper site, which is an active manufacturing facility, was gated with warning signs posted in both English and Spanish. The gates are open during business hours. A high level of truck and forklift traffic was observed, with no apparent safety hazards noted. The vacated Tweedy site was entirely fenced, with a locked gate, and No Trespassing signs. Therefore, no physical hazards at the site are accessible to the public.
As with similar industries, many physical hazards are present for workers. The owners of the facility and the Occupational Safety and Health Administration (OSHA) are responsible for the proper training of personnel about the physical, as well as chemical, dangers. The owners are required to provide proper protective equipment for the employees and instruct personnel how to use the equipment properly. If that is done, workers should be protected.
To determine whether nearby residents are exposed to contaminants migrating from the site, ATSDR evaluates the environmental and human components that lead to human exposure. An exposure pathway consists of five elements: A source of contamination, transport through an environmental medium, a point of exposure, a route of human exposure, and an exposed population.
ATSDR categorizes an exposure pathway as a completed or potential exposure pathway. In completed exposure pathways, the five elements exist and indicate that exposure to a contaminant has occurred in the past, is occurring, or will occur in the future. In potential exposure pathways, however, at least one of the five elements is missing but could exist. Potential exposure pathways indicate that exposure to a contaminant could have occurred in the past, could be occurring now, or could occur in the future. An exposure pathway can be eliminated if at least one of the five elements is missing and will never be present.
Table 6 identifies the completed exposure pathways, and Table 7 identifies the potential exposure pathways. The discussions in this section incorporate only those pathways that are important and relevant to the site. We also discuss some of those exposure pathways that have been eliminated.
As shown in Table 6, Appendix B, existing information for the Cooper site indicates three completed exposure pathways exist by which site-related contaminants may impact people in the surrounding area. These pathways include surface soil, groundwater, and ambient air.
A past exposure to contaminated surface soil, particularly by students at Tweedy School, existed prior to the excavation and paving of the 2 by 40-foot planter area along the north border of the school in April 1987 (2). The unpaved area was on the school playground about 5 feet from the outdoor covered student lunch area, and students had unrestricted access to this area during recess and lunch periods. No records are available as to whether more of the Tweedy playground was unpaved prior to 1986. Playground activities, such as balls rolling onto the unpaved area, could bring children into contact with the contaminated soil. School records indicate that 582 students (grades K through 5) and 64 staff attended Tweedy School in 1987, with the student population divided into three tracks of a year-round schedule so that only 2/3 of the students attended on any given day.
Skin contact, inhalation of soil dust, and incidental soil ingestion are likely routes of exposure to contaminated soil. Soil ingestion can be an important route of exposure, especially for children less than 6 years of age, because of their greater hand-to-mouth activity (38). Kindergarten children at Tweedy School would have been age 4.9 to 6. Young children typically ingest about 200 milligrams (mg) soil per day while adults and older children ingest less than 100 mg per day. Children who demonstrate pica behavior, a tendency to eat non-food items such as dirt, may ingest up to 5,000 mg per day. However, children of school age would not be expected to show pica behavior.
The contaminants in the surface soil sample taken in December 1986 were shown to be total hydrocarbons at 90,000 ppm, but no record exists as to whether a pH was taken. A more detailed sampling done after the April 1987 release to Tweedy School indicated that the surface soil was extremely basic from the sodium hydroxide, with a pH of 14. The sodium hydroxide would not tend to evaporate, so that the main route of entry to the body would have been through skin contact with or ingestion of the contaminated soil.
A past exposure pathway existed for Cooper Drum workers to contaminants from the surface soil prior to the major soil removal and paving of the entire site in 1986 (4). Approximately 70 workers were employed at Cooper in 1989 (11).
A LACHD inspection in 1984 revealed degraded asphalt conditions and spillage from drums onto the ground surface. Soil samples taken in 1984 showed contamination by PCE and other solvents, PCBs, and various heavy metals (11). Workers were exposed to contaminants in the soil through inhalation of volatile compounds and soil dust, ingestion of soil dust, or skin contact with the contaminated soil. The amount of exposure is not possible to estimate because no surface soil monitoring was done.
On-site workers, Tweedy staff and students, and South Gate residents were exposed to PCE in the municipal well water until December 1986. At that time, the 4 municipal drinking water wells located at the nearby Recreation Park were removed from service because of PCE levels above the state health limit of 5 ppm. One of these wells also contained TCE levels above the comparison value. In 1991, 3 more municipal wells were closed because of PCE contamination. Although several other volatile organic chemicals, including benzene and several chlorinated hydrocarbons, were found in on-site monitoring wells, only PCE and TCE were found in the much deeper municipal well water aquifer. All of the municipal wells maintained by the City of South Gate are interconnected, and the City also blends its well water with water received from Metropolitan Water District. Because no municipal well monitoring was done prior to 1986, it is impossible to determine how long, or at what levels, earlier exposures may have occurred.
The routes of exposure to PCE and TCE in drinking water include inhalation, ingestion and skin contact. Because PCE and TCE are very volatile, inhalation of PCE and TCE mists or vapors may have occurred during showering, bathing, or washing.
Present and future exposure to contaminants in municipal drinking water is eliminated as a pathway because regular well water monitoring would detect contamination before the water is distributed and because a treatment plant to remove contaminants from the four closed drinking water wells in South Gate Recreation Park is operational (39).
The South Gate municipal water district is used by over 75,000 residents within 4 miles of the site. Well monitoring showed a range of PCE values from 2 ppb to 14 ppb within a one-mile radius of the site. However, it is impossible to determine the actual levels reaching residents because the values do not reflect levels that were at the household drinking water tap. Also, the levels in the distributed water depended on how much water was pumped from individual wells within the system on any given day (40).
Tweedy staff and students were exposed to contaminants in ambient air prior to the removal of students to temporary buildings two blocks southwest of the old site in 1988. Additionally, 58 LAUSD administrative staff were exposed to airborne contaminants until they vacated Tweedy in 1992. Those exposures were likely at levels below those prior to 1988 because of efforts made to reduce air emissions (such as covering open tanks, etc.). Present exposure to people at the school to ambient air contaminants originating from the Cooper Drum site is eliminated because the school site is currently vacated.
As shown in Table 5, the contaminants of concern were hydrogen chloride, chlorinated solvents (chloroform, carbon tetrachloride, TCE, PCE, and methylene chloride), and one aromatic hydrocarbon (toluene). Although levels were found to be only slightly higher than background, as shown in 8-hour averaged samples, samples collected for short time durations showed very high levels of hydrogen chloride and significant levels of chloroform, methylene chloride, and toluene. Therefore, some short-term exposures are assumed to have occurred to high levels of contaminants.
In addition, offsite soil contaminants may have evaporated from the soil into the air in the unpaved planter area on the playground. As shown in Table 3, the hydrocarbons found in Tweedy subsurface soil at levels above comparison values were 1,1-DCA, PCE, and TCA, and total petroleum hydrocarbons. These would tend to evaporate quickly from the soil, so inhalation would be the main route of entry into the body.
Cooper Drum workers were exposed to airborne contaminants from the materials used in cleaning and painting used drums and fabricating and painting new drums. This exposure pathway was documented in the past by the August 1984 LACHD inspection in which Cooper was advised to provide respirators to paint booth workers and eliminate spillage from drums (5).
Unprotected workers in areas where those processes took place inhaled contaminants in the form of vapors from volatile solvents, dusts from the buffing of drums, fumes from welding, or mists from spray painting. However, no exposure monitoring records are available to determine actual exposure levels to workers. The current owner, Waymire Drum, has plans to conduct worker exposure monitoring to lead, paint spray, and acid and caustic mists in the near future (41).
People on and near the Cooper site are potentially exposed to a variety of volatile organic chemicals in the ambient air on and around the Cooper site. Table 5 lists the average and maximum 24-hour background levels of some air contaminants. Further air monitoring is needed to determine the sources of these contaminants and make recommendations for reduction of contaminant levels in air. The problem of background air pollution is of concern to the entire Los Angeles basin.
Additionally, an important potential exposure pathway exists if lead dust accumulates in clothing and shoe bottoms and is carried home from the workplace. The dust could be inhaled as airborne particulates or settle to become dust on floor and furniture. Once settled, the contaminated dust could be ingested when objects are put into people's mouths, a common behavior for children.
In this section we will discuss possible health effects experienced by people exposed to specific contaminants, evaluate state and local health data bases, and address specific community concerns.
Past exposure of Tweedy school staff and students, Cooper Drum employees, and surrounding residents and workers to air contaminants is documented through data presented in the Environmental Contamination and Other Hazards section. The TRI data report air releases for a number of chemicals, including those for which data are presented in Table 5. The chemicals which are documented in Table 5, and also reported by TRI data, include PCE, TCA, methylene chloride, and toluene. These chemicals are discussed in this section.
It is likely that present and future exposure to air contaminants will occur, given the known industrial releases in the area. Currently available data are not sufficient to estimate exposure duration or levels of contaminants, which can then be compared with health comparison values. Therefore, actual health impact resulting from exposure cannot be evaluated.
Cooper Drum workers, Tweedy School students and staff, and residents and workers in the South Gate area near the site were exposed in the past to perchloroethylene (PCE) through inhalation of the contaminant released to the air. The limited 1986 air sampling data available from both SCAQMD and LACHD document the presence of PCE at levels below which people normally can smell PCE (5 ppm) in air. However, the regional background maximum PCE value of .012 ppm did exceed ATSDR's intermediate MRL of 0.009 ppm. As Table 5 shows, PCE site sampling results were lower than the background maximum, indicating area-wide contamination.
People living and working in the area are likely exposed to PCE in the air now, and exposure will likely continue in the future. Cooper Drum is only one of a number of possible sources of PCE air contamination in the area. The Toxics Chemical Release Inventory for 1987 through 1990 reports PCE releases to the air by a number of industrial facilities in the area surrounding the Cooper Drum site. However, the information available cannot be used to estimate a level which people may actually be breathing.
South Gate residents and workers were exposed in the past to PCE through drinking PCE-contaminated water. The City of South Gate took 4 municipal wells out of service in December 1986, and 3 additional wells in 1991 because of the presence of PCE above allowable drinking water levels. Based on the available information, it is not possible to determine exposure duration or level. Prior to 1987, the City of South Gate did not regularly check its municipal wells for PCE; thus, how long people may have been exposed cannot be determined. Also, no information is available about past PCE levels actually present in tap water delivered to homes and businesses from municipal wells maintained by the City of South Gate. Most likely those homes and businesses closest to the affected wells received tap water containing the highest levels. However, all of the municipal wells maintained by the City of South Gate are interconnected, and the City also blends its well water with water received from Metropolitan Water District. Given these uncertainties, it is not possible to estimate an exposure dose which can be compared with ATSDR's intermediate MRL for PCE.
Present and future exposure to PCE in drinking water is unlikely because the City of South Gate is regularly monitoring its municipal wells to ensure the safety of distributed water.
PCE is a man-made volatile organic compound (VOC) that is commonly found in the environment (42). Other names for the compound include tetrachloroethylene and tetrachloroethene. Commonly used for dry cleaning fabrics and metal-degreasing operations, it is also released to the environment by way of industrial emissions and building and consumer products. Common consumer products containing PCE include auto brake parts, water repellents, spot removers, adhesives, and wood cleaners. A liquid at room temperature, it evaporates easily and can migrate through soil to groundwater (42).
In general, PCE levels in air are higher in cities or industrial areas than in more rural or remote areas. Reported background levels of PCE in air are far less than 1 ppm. People can smell it at levels of 5 ppm (42).
People with the greatest chance of exposure to PCE are those who work with it. When concentrations in air are high, especially in closed, poorly ventilated areas, single exposures to PCE can cause dizziness, headache, sleepiness, confusion, nausea, difficulty in speaking and walking, and possibly unconsciousness and death. Skin irritation can result from repeated or extended contact with the chemical. Health effects of breathing in air or drinking water with low levels of PCE are not known (42).
Animal studies, conducted with amounts much higher than those most people are exposed to, show that PCE can cause liver and kidney damage and liver and kidney cancers. However, it has not been shown to cause cancer in people. EPA considers PCE to be a probable human carcinogen (42).
Cooper Drum workers, Tweedy School students and staff, and residents and workers in the South Gate area near the site were exposed in the past to trichloroethylene (TCE) through inhalation of the contaminant released to the air. The limited 1986 air sampling data available from both SCAQMD and LACHD document the presence of TCE at levels above ATSDR's comparison value (CREG) and at or above regional background values. TCE was also found in some municipal wells, but not at levels that are expected to cause adverse health effects.
TCE is a man-made chemical mainly used as a solvent to remove grease from metal parts (43). Some products that contain TCE include paints and paint removers, glue, spot removers, and metal cleaners. It evaporates easily into air and breaks down to phosgene, a lung irritant. TCE also moves easily through soil into groundwater (43).
People can become exposed to TCE by breathing air or drinking water containing it. People exposed to high air levels of TCE can become dizzy or sleepy. Health effects related to low exposures over a long period of time are not known (43).
Although the carcinogenic potential of TCE is under study, EPA has developed a cancer slope factor for inhalation of TCE. If people breathed 0.98 ppb TCE over a lifetime, those people would not be expected to have an increased risk of developing cancer (43).
Methylene chloride was found in short term ambient air samples at levels below what would result in a dose equal or greater than the intermediate MRL of .03 ppm. However, it was also shown to be emitted by surrounding facilities on the TRI data for 1987 and 1988.
Methylene chloride, also known as dichloromethane, is widely used as an industrial solvent and as a paint stripper (44). It evaporates easily and is mainly released to the environment in air. Background levels in air are usually less than 1 ppb. People can usually smell methylene chloride at about 200 ppm in air (44).
The highest and most frequent exposures to methylene chloride usually occur in workplaces where the chemical is used. Breathing methylene chloride at levels between 300 to 800 ppm for short periods of time (3-4 hours) can result in impaired vision and hearing, eye irritation, dizziness, nausea, tingling, and loss of coordination. In most cases, effects disappear after exposure ends. Animal studies also show changes in the liver and kidney, but similar effects have not been observed in humans (44).
Methylene chloride has not been shown to cause cancer in humans exposed to vapors in the workplace. However, breathing high concentrations of methylene chloride for long periods of time did cause cancer in mice. EPA considers methylene chloride to be a probable human carcinogen (44).
Cooper Drum workers, Tweedy School students and staff, and residents and workers in the South Gate area near the site were exposed in the past to toluene through inhalation of the contaminant released to the air. Levels detected in the 1986 sampling conducted by SCAQMD and LACHD show short-term levels at three times ATSDR's acute inhalation MRL (45).
People living and working in the area are likely exposed to toluene in the air now, and exposure will likely continue in the future. Cooper Drum is only one of a number of possible sources of toluene air contamination in the area. Toluene was reported as a TRI release in 1987, 1988, 1989, and 1990.
Toluene is a clear, colorless liquid with a sweet smell (45). Widely used in industry as a solvent, it is also commonly found in gasoline, paints, paint thinners, adhesives, nail polish, cosmetics, inks, and stain removers (45).
Exposure to toluene happens mostly through breathing the chemical in the workplace or during deliberate glue sniffing or solvent abuse. Toluene readily evaporates and is quickly released to the air when toluene-containing products are used. Automobile exhaust and cigarette smoke also puts toluene into the air. Toluene levels in air are usually less than 1 ppm in cities and suburbs that are not close to industry. It can be smelled in air at a level of about 8 ppm (45).
Exposure to toluene can lead to harmful effects on the central nervous system. These effects depend on both the amount and length of exposure. Low to moderate, continuous exposure in the workplace can cause tiredness, confusion, memory loss, nausea, and loss of appetite and coordination. These symptoms disappear when exposure is stopped. Researchers do not known if the low levels of toluene present in the work setting will cause any permanent effects on the brain or body after many years. Long- term exposure to toluene through intentional use such as glue sniffing can cause permanent brain damage. Long-term exposure to low and moderate amounts may also have some effect on kidney function (45).
Studies in workers and in animals exposed to toluene indicate that toluene is not a carcinogen. EPA has determined that toluene is not classifiable as to its human carcinogenicity (45).
Cooper Drum workers, Tweedy School students and staff, and residents and workers in the South Gate area near the site were exposed in the past to 1,1,1-trichloroethane (TCA) through inhalation of the contaminant released to the air. TCA is present in onsite and offsite subsurface samples, offsite ambient air samples, as well as reported in TRI data for 1987, 1988, 1989, and 1990. No MRL's exist to evaluate the public health implications of TCA (46).
The man-made chemical TCA has many industrial and household uses (46). As a solvent, it serves as a degreasing agent. It is commonly found in spot cleaners, glues, aerosol sprays, paints, household, and office products (46).
TCA evaporates easily into air. People can smell it in air at levels greater than 100 ppm. Human health effects resulting from long term exposure to air containing specific levels of TCA are not known. Mild nervous system effects, eye irritations, and liver effects have been noted with short term exposures (5 minutes to 3 hours) to air containing 175 to 2,650 ppm (46). These levels are much higher than those found near the site.
EPA considers TCA to be not classifiable as to carcinogenicity for humans (46).
Tweedy staff and students may have been exposed to hydrogen chloride inhalation of mists or vapors from the Cooper drum process area prior to the vacating of Tweedy as a school site in 1988 and as an administrative staff site in 1992. The occupational guideline (TLV) for worker exposure to hydrogen chloride is a ceiling limit of 5.0 ppm, which is based on an 8-hour average exposure by workers day in and day out over a 40-year worklife. The ceiling limit indicates that exposure may not exceed 5.0 ppm at any time of the day (47). The highest short-term (3-hour) sample taken on the Tweedy playground was, in fact, above the occupational ceiling limit. This is of particular concern because the general population, including schoolchildren, is considered to be more susceptible to adverse effects from contaminants than healthy workers.
There is no comparison health value for nonoccupational exposure. Limited sampling by LAUSD in 1986 detected levels of hydrogen chloride on the Tweedy playground that exceeded the occupational ceiling limit. Acute effects of eye and throat irritation described by Tweedy School staff and students were among symptoms that can be associated with hydrogen chloride exposure (48).
Workers at the Cooper site may have been exposed in the past and present to hydrogen chloride mists and vapors from the acid drum cleaning line in the main process area. No industrial hygiene studies exist, and workers were observed in this area without respiratory protection during our site visit of October 1992.
Hydrogen chloride is used to produce chlorinated organic chemicals, dyes and dye intermediates, and for steel-pickling and for cleaning operations (48).
Hydrogen chloride is a strong irritant of the eyes, mucous membranes, and skin. The major effects of acute exposure are usually limited to the upper respiratory tract and are sufficiently severe to encourage prompt withdrawal from a contaminated atmosphere. There do not appear to be any long-term effects, such as cancer, except for tooth erosion, which may occur at high exposure levels. Warning properties are good; most people can detect the presence of hydrogen chloride at 5 ppm (48).
Tweedy School staff and students may have been exposed to sodium hydroxide by skin contact and possibly ingestion of contaminated soil in the planter boxes and liquid oozing through the south wall of the Cooper main process building prior to April 1987. The surface soil was measured at pH 14. However, no records exist documenting skin burns or other incidents in which Tweedy staff or students showed acute effects from sodium hydroxide. Tweedy School staff and students did complain of eye and throat irritation, symptoms that can be associated with sodium hydroxide exposure (48).
Workers on the Cooper site may have been exposed to sodium hydroxide by skin contact, ingestion, and inhalation in the past, present, and future. In the drum cleaning process, sodium hydroxide is heated to 140 degrees F, releasing a strong, caustic smell. No records of industrial hygiene monitoring of workers exist, and no respirators were being worn in this area during our site visit in October 1992.
Besides metal cleaning, sodium hydroxide is used in various manufacturing processes, including rayon, mercerized cotton, soap, paper, aluminum, and petroleum products (48). It is also used for the electrolytic extraction of zinc, tin plating, and oxide coating. Sodium hydroxide is not found as a background contaminant in ambient air because it is not very volatile (48).
The main effects of sodium hydroxide are immediate, short-term (acute) effects, including mild to severe irritation of the eyes, mucous membranes, and skin, and pneumonitis. There do not appear to be any long-term effects such as cancer. In industrial settings, the main concern is skin contact with solid or liquid solutions of sodium hydroxide. However, exposure to mists or dust may cause multiple small burns with temporary loss of hair. Ingestion produces severe abdominal pain, severe burn damage to the upper respiratory system, and vomiting (48).
Lead exposure to onsite workers was documented by blood lead sampling in September 1992. However, no workplace lead monitoring has been done to correlate blood lead levels with ambient air levels of lead. One of the five workers tested showed a level of 25 micrograms/deciliter of blood. The Occupational Safety and Health Administration determined that blood lead levels of 40 µg/100 grams whole blood is of concern; that level has not been changed since 1978 (49). The Centers for Disease Control and Prevention does not issue safety levels for workers. However, for children, blood lead levels over 10 µg/deciliter are considered elevated.
An important potential pathway for lead exposure is dust carried home from the workplace and passed on to worker families, particularly children.
Lead is a naturally occurring bluish-gray metal. It is used for battery manufacturing, ammunition, soldering, pipes, as a gasoline additive (now no longer legal in the U.S.), in paints, and ceramic products (49).
Exposure to lead can damage the brain and kidneys of adults and children. Lead exposure can increase blood pressure in men, but it is unknown whether this effect can occur in women. Also, a man and woman may have trouble having children if the man is exposed to high levels of lead. Lead exposure may affect his sperm or damage other parts of the male reproductive system. While lead has not been shown to cause cancer in humans, animal studies have shown that lifetime lead exposure in rodents can cause cancer (49).
Lead exposure is especially dangerous for unborn children because they can be harmed during fetal development. Pregnant women exposed to lead can pass lead to unborn children, causing premature birth, low birth weight, and miscarriages. Young children are also more vulnerable because their developing brain cells may be damaged and their growth impaired (49).
In response to community concerns after the Purex chlorine gas leak in February 1986, the Toxicology and Epidemiology Program (TEP) of LACHD conducted the following four-part study: 1) absentee patterns of students at Tweedy School; 2) a questionnaire of health effects of staff at Tweedy School; 3) a community survey in the nearby neighborhood alleged to have an unusual occurrence of cancer; and 4) a review of air monitoring performed at Tweedy School by LAAQMD. The summary of results from this study was released in November 1986 (13). In addition, TEP released a study of Tweedy School children symptoms and physical exam results in March 1987 (50) and a study of biological monitoring of a self-selected group of Tweedy students and staff in April 1987 (51).
- Student absentee patterns
- Staff health and odor complaints
- Investigation of alleged cancer cluster
- Review of air monitoring results
- Symptoms and physical exam results of Tweedy School children
- Biological monitoring of Tweedy School children and staff
This study did not detect meaningful differences in overall rates of absences at Tweedy compared to the control school or in daily rates of absences before or after odor complaints. The study stated that, if health effects were being experienced by the students, they did not appear to be health effects that result in school absences. A recommendation was made that any further study of Tweedy students focus on short-term health effects such as eye, nose and throat irritation, nausea, and headaches. Because a 50% turnover rate per year was found among students, a recommendation was also made that the amount of time a student had attended Tweedy be considered. No further study was done, and the students were moved in July 1988 to temporary buildings two blocks away. Additionally, no records exist documenting skin burns or other incidents in which Tweedy staff or students showed acute effects that may be associated with contact with very high pH soils.
The results of this survey showed no clear association between odor complaints and symptoms by the 58 Tweedy staff respondents. The overall health status of Tweedy staff did not differ from the United States population as a whole. The same number of persons stated that odors had gotten better in the previous year as stated that odors had gotten worse. Fifty-two of the 58 respondents detected unpleasant or unusual odors at the school, and 35 of them detected odors more than once a week.
An alleged cancer cluster in the 5300 block of Batavia Road, 0.7 miles south of Cooper, was investigated by LACHD/TEP, and no cancer cluster was found.
LAAQMD took air samples of solvents on four separate days during July 1986, at four locations on Tweedy School grounds. Overall concentrations of all solvents were fairly low. However, toluene, TCA, TCE and PCE were found consistently at levels slightly higher than at control locations. LACHD/TEP postulated that these four solvents may have a common source. They determined that the levels of exposure would be unlikely to cause long-term health problems at Tweedy School. They stated that these results do not rule out the possibility of brief higher-level exposures which might be associated with irritative symptoms. Monitoring of odor complaints was determined to be sufficient to rule out such exposures. The results of the October 23, October 28, and December 2, 1986, short-term sampling were not considered in the LACHD epidemiological study because the survey was taken after that study was completed.
The short-term sampling indicated that much higher levels of some contaminants existed than the 8-hour averages indicated. These high level excursions may be responsible for acute upper respiratory irritations such as burning eyes, and throat irritation experienced by Tweedy school staff and students (52).
TEP reviewed results of physical examinations, analyzed symptom surveys, and conducted pulmonary function tests. Rates of reported symptoms were in the range that is expected in a non-exposed population, physical examination results were unremarkable, and pulmonary function tests were normal for the group as a whole (50).
TEP reviewed the results of blood and urine specimens collected from self-selected children and staff by an independent physician. Results indicated that there may have been airborne exposure to TCA but in ranges that are not likely to produce any known long-term health effects, although short-term irritative symptoms might have resulted in some individuals (51).
In September 1992, biological monitoring for lead in the blood of five current employees who work in the paint spray and buffing area were taken. No previous reports of worker health effects were available. Blood lead measurements show exposure to lead of approximately two times the normal level for the general population in two of the five workers. All five results were well below the California Occupational Safety and Health Administration (Cal\OSHA) levels for action. No air monitoring has been done to date to verify the exposure source of these biological samples. However, lead is a constituent of some of the paints currently used, and is also encountered while buffing used drums before repainting (15, 41).
In the course of preparing this public health assessment, we did not discover any current community health concerns. In this section, we will address several health concerns posed by the community in the past. They are as follows:
- Are the health complaints of the children and staff at Tweedy School related to the environmental contaminants found at Cooper Drum?
- What is the long-term effect of the chemical pollution on my child's health?
- Are residential reports of higher than normal cancer-related deaths true?
- Is there a connection between odors and illnesses experienced by the teachers and staff at Tweedy School?
In 1986 and 1987 several studies were conducted by Toxics Epidemiology Program in the Los Angeles County Department of Health Services. These studies are discussed in the Health Outcome Data Evaluation section. The general conclusion was that the rates of symptoms and the absentee rates of students indicated that no major health-related effects had occurred. Absentee rates were similar to those of a control school and the rates of symptoms were in the range of what would be expected in the general population. These studies did indicate that symptoms had been reported that were short-term and reversible in nature. A suggestion that the location of Tweedy, adjacent to a heavily industrial area, was not appropriate appeared in the study.
This is a difficult question to answer because Tweedy School was in the middle of a heavily industrialized area and there was daily exposures to a multitude of chemicals - some known and some unknown. Environmental science is a comparatively new and, therefore, inexact science, but based on the information that was available at the time of the exposure in the mid to late 80's and based on the studies carried out by the Los Angeles County Department of Health Services, the effects of the exposure appeared to be short-term and reversible.
An alleged cluster of 18 cancer cases was reported to exist in a two block area of South Gate. The Environmental Toxics Program investigated the report and, after making numerous attempts to contact the residents, was unable to identify any type of cluster.
In the staff health and odor complaint study, there was no clear association between odor complaint and symptoms. The symptoms and physical examination study of students at Tweedy showed that there was a weak association between complaints about physical odors and certain symptoms including headache, cough, irritation of the eye, nose, and throat, school performance, alertness, and fearfulness. This could mean that symptoms were caused by or exacerbated by chemical odors or that children with symptoms were more likely to notice and complain about the chemical odors.
Public Comments on This Document
The public comment period for review of the draft public health assessment for Cooper Drum occurred from December 8, 1993, to January 7, 1994. We prepared a one-page announcement/fact sheet to be distributed through the local newspaper, the Los Angeles Times, to all mailing addresses within the zip code surrounding the site (Appendix C). The announcement was written in both Spanish and English. In addition, we requested the current site operator, Waymire Drum, to distribute the announcement to all current employees. Copies of the draft health assessment were available at the South Gate Public Library, Tweedy School, and Waymire Drum. Copies were also sent to interested members of the public whose names had been acquired during the preparation of the report.
No comments or concerns from the public were brought to our attention during the public comment period. However, the environmental manager for Waymire Drum did respond to the worker health and safety recommendations with a detailed letter describing its safety program (Appendix D).