Skip directly to search Skip directly to A to Z list Skip directly to site content

PUBLIC HEALTH ASSESSMENT

OMEGA CHEMICAL SITE
(a/k/a OMEGA CHEMICAL CORPORATION
WHITTIER, LOS ANGELES COUNTY, CALIFORNIA


SUMMARY

The California Department of Health Services (CDHS) has prepared this public health assessment under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). The public health assessment is a mechanism to provide the community with information on the public health implications of specific hazardous waste sites and to identify those populations for which further health actions or studies are indicated.

The Omega Chemical site, which is approximately 40,000 square feet in area, is located between 12504 and 12512 East Whittier Boulevard in the City of Whittier, Los Angeles County, California (1). Prior to 1976, the site housed several different industrial operations. These included: a bullet manufacturer (until 1963), a business that converted vans to ambulances (1966 to 1971), and a chemical processing facility (1971 to 1976) (1). From 1976 to approximately 1991, the Omega Chemical Corporation and Omega Refrigerant Reclamation (which will be referred to as the Omega site), operated as a spent solvent and refrigerant recycling and treatment facility handling primarily hydrocarbons and chlorofluorocarbons (1). The hazardous wastes stored on the Omega site consist of mainly chlorinated and aromatic solvents. Due to past mishandling and/or improper storage of the chemicals and wastes on the Omega site, high concentrations of volatile organic compounds (VOCs) have impacted the soil and groundwater. The Omega site was nominated to the National Priorities List (NPL) on September 29, 1998 by the United States Environmental Protection Agency (USEPA).

CDHS identified soil gas migration as a potential exposure pathway for on- and off-site workers, and residents in the vicinity of the Omega site. Potential soil gas migration into buildings on and off the site may pose a current and future health concern. Because of the lack of indoor air data, it is not possible, at this time, to determine the impact of the contaminants in the soil gas upon the in-building air. This pathway was designated "potential" until further evaluation of the in-building air is conducted. Thus, potential soil gas migration into buildings on and off the site may pose a current and future health concern.

In addition, CDHS determined that contaminated groundwater may pose a future health concern to individuals exposed to it. Specifically, private wells may exist in the vicinity of the Omega site and one of the City of Santa Fe Springs's municipal wells, DWR #2S/11W-32G3, is located approximately 1 mile downgradient of the groundwater contamination. Since exposure to the groundwater is a possible future scenario that could occur if remediation of the contaminated groundwater fails to stop the migration of the groundwater plume, CDHS estimated both non-cancer and cancer doses for children and adults potentially drinking the groundwater. Several of the estimated non-cancer doses exceeded ATSDR's Minimal Risk Levels (MRLs, Appendix B: Glossary), thus, non-cancer health effects could occur if the contaminants measured in the groundwater on-site migrated and impacted private groundwater wells or the City of Santa Fe Spring's municipal wells. Also, CDHS estimated the cancer risk for the contaminants that are carcinogens via the ingestion route and determined that a high increased cancer risk is predicted if the groundwater contaminants from the Omega site impacted the area's drinking water supply.

Contaminated groundwater from the Omega site does not appear to pose a past, current, or future health concern to the citizens of the City of Whittier who drink municipal water. The municipal groundwater wells that belong to the two municipal water suppliers for the City of Whittier are located in the City of Industry, which is located approximately 3.25 miles north of the City of Whittier. Because groundwater contamination from the Omega site is moving in a southwest direction, it does not and will not likely have any health impact on the City of Whittier's municipal water supply.

According to the USEPA, there are no known private domestic groundwater wells that are in use downgradient or in the vicinity of the Omega site. However, a well survey would need to be completed to confirm this. Until a well survey can be completed, the use of contaminated groundwater from private domestic wells must be considered a potentially completed exposure pathway.

Based on the review of available data, CDHS believes that the Omega site poses an indeterminate public health hazard.


BACKGROUND

The California Department of Health Services (CDHS) has prepared this public health assessment under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). ATSDR, located in Atlanta, Georgia, is a federal agency within the United States Department of Health and Human Services. ATSDR is authorized under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980 to conduct public health assessments at hazardous waste sites on the National Priorities List (NPL). This public health assessment (PHA) evaluates the public health significance of the Omega Chemical site (which will be referred to as the Omega site in this document) and is based on a review of environmental sampling data and consultation with involved agencies and the community.

A. SITE DESCRIPTION AND HISTORY

The Omega site, which is approximately 40,000 square feet in area, is located between 12504 and 12512 East Whittier Boulevard in the City of Whittier, Los Angeles County, California (Appendix A: Figures 1 and 2). There are two buildings on the Omega site: a 24,000 square foot warehouse and a 2,400 square foot administrative building. The Omega site is paved with concrete and is surrounded by a 7-foot high chain link fence topped with razor wire (1).

Prior to 1976, the site housed several different industrial operations. These included: a bullet manufacturer (until 1963); a business that converted vans to ambulances (1966 to 1971); and a chemical processing facility (1971 to 1976) (1).

From 1976 to approximately 1991, the Omega Chemical Corporation and Omega Refrigerant Reclamation, operated as a spent solvent and refrigerant recycling and treatment facility handling primarily hydrocarbons and chlorofluorocarbons (1). The Omega site received and processed drums and bulk loads of waste solvents and chemicals from various industrial activities to form commercial products that were either returned to the generators or sold in the marketplace. The hazardous wastes stored on the Omega site consist of mainly chlorinated and aromatic solvents. In June 1995, before removal activities, there were thousands of drums of hazardous waste, two roll-off bins of hardened resin material, hundreds of empty contaminated drums, numerous cylinders weighing from 15,000 to 20,000 pounds, and various other smaller containers of waste and/or hazardous waste stored on the Omega site (2). In addition, there were several hundred 55-gallon drums containing chemical products and hazardous materials stored in the warehouse on the Omega site.

Between 1985 and 1988, three environmental investigations were conducted at the Omega site under the oversight of the Los Angeles County Departments of Health Services (LACDHS), Public Works (LACDPW), and Fire (LACFD) (1). These investigations included sampling of the soil gas (i.e., contaminants in soil and/or groundwater volatilize, resulting in contaminated gases migrating upward through the soil air space), soil and groundwater beneath the Omega site. In 1985, LACDHS' environmental contractor, Crandall, collected subsurface soil samples near the western corner of the Omega site. Volatile organic compounds (VOCs) were detected from five shallow soil borings (approximately 3.5 feet below ground surface) (1).

In 1987, Fred R. Rippy, Inc. (a previous business owner and operator at the Omega site) hired an environmental consulting firm, Leighton & Associates, to document the removal of a 500-gallon underground storage tank (UST) and to sample the contents of the UST and surrounding soils. The contaminants in the soil and the UST included: total hydrocarbons, total VOCs, and acetone. In 1988, two environmental investigations were conducted at the Omega site to assess the subsurface conditions. The environmental consulting firm, Environmental Research & Technology (ER&T) conducted a soil gas survey for the Omega site. ER&T detected elevated concentrations of VOCs in the soil gas across most of the Omega site, with the exception of the northeastern corner. VOCs were reported in a qualitative format without actual concentration values (1). During that same year, soil and groundwater sampling was conducted by ENSR Consulting & Engineering (formerly ER&T). The VOCs detected in five soil borings (ranging from 5 to 75 feet below ground surface) included: tetrachloroethylene (PCE), Freon 113, trichloroethylene (TCE), and methylene chloride (1). Other VOCs were detected less frequently and/or at lower concentrations (1). In addition, three groundwater samples were collected and analyzed from monitoring well BMW-1 (installed in the western portion of the site). The contaminants in the groundwater included: Freon 113; and lower concentrations of trichloroethane (TCA), Freon 11, 1,1-dichloroethene (1,1-DCE), and PCE (1).

Since 1991, the California Department of Toxic Substances Control (DTSC) and the United States Environmental Protection Agency's (USEPA) Hazardous Waste Management Division have been actively trying to get the owner/operator to remove the wastes and clean up the Omega site (2). On May 9, 1996, USEPA issued CERCLA Administrative Order No. 95-15 to the owner of the Omega site and to generators of hazardous waste that had shipped major quantities of material to the Omega site requiring them to clean up the Omega site (2). The owner of the Omega site and the generators of hazardous waste will be referred to as the "responsible party group." This Administrative Order was carried out in two phases.

During 1995, USEPA's Superfund Emergency Response Office oversaw Phase I Drum Removal Activities (DRA), during which the responsible party group removed over 4,000 steel and polyethylene 55-gallon drums from the outside storage pad, administration building, and warehouse (1,2). These drums, as well as recovered and generated liquids, were removed to various off-site treatment, storage and disposal facilities (TSDFs) (1). In addition:

  • approximately 60 cubic yards of solidified resins stored on the Omega site were removed to an off-site facility for incineration;
  • five 5,000-gallon above-ground storage tanks (ASTs) were sampled, emptied, and disposed at a landfill; the contents were incinerated at an off-site facility;
  • two rainwater sumps and four evaporators on the southern portion of the site were pumped out, and the rinsate transported to an off-site TSDF;
  • two 500-gallon empty cooling towers were cleaned and confirmation wipe samples were obtained;
  • approximately 40,000 gallons of rinsate and decontamination water were transported to an off-site TSDF;
  • sixty-seven refrigerant gas cylinders were sent off-site for reclamation or destructive incineration. A total of 165 empty or usable cylinders were left on the Omega site at the completion of the DRA; and
  • following removal of the drums and hazardous materials, the remaining facility process equipment and structures were decontaminated and wipe sampled in accordance with the USEPA-approved DRA Workplan (1).

Phase II activities began in November 1995 and included the collection and analysis of subsurface soil, groundwater, and soil gas at the Omega site by the responsible parties (1). This PHA evaluated the soil, groundwater, and soil gas data obtained during the Phase II activities to determine if there are current and future exposures to on-site related businesses and the community in the vicinity of the Omega site. Based on the analytical results obtained during the Phase II activities, the contaminants detected in the subsurface soil include: PCE, TCE, 1,1-DCE, Freons and other chlorinated hydrocarbons, and metals (1). The contaminants in the groundwater included: PCE, Freons and other chlorinated hydrocarbons. In addition, a groundwater plume contaminated with PCE has migrated downgradient of the Omega site. This contamination appears to have migrated in a southwesterly direction. However, the vertical and horizontal extent of the contamination is not currently known. The contaminants detected in the soil gas include: Freon 113, Freon 11, PCE, and TCA (1). Currently, USEPA is in the process of conducting an in-depth investigation of the Omega site and evaluating cleanup alternatives.

B. SITE VISIT

On July 17, 1999, two CDHS staff members, Sherry Chan and Primitivo Rojas, visited the Omega site. The Omega site is located in a mixed residential and industrial area. Across Whittier Boulevard, there is a residential neighborhood. There are many businesses adjacent and near the Omega site.

Ms. Chan and Mr. Rojas met with the current site tenant who was planning to manufacture plastic furniture in the warehouse on the Omega site. This individual gave CDHS staff a brief tour of the warehouse. The Omega site is surrounded by a metal fence topped with razor wire. There were three caution signs posted on the front metal fence entrance, "Beware of Dog," "Peligro Personal Autorizado Solamente" (which translates to "Danger Authorized Personnel Only"), and a chemical placard (that used numbers and color signs to define the basic hazards of specific chemicals that are used on-site). The site is covered with concrete (both inside the warehouse and outside in the yard area). The properties adjacent to the Omega site are also covered with concrete.

During the site visit, both entrances of the warehouse were opened. The warehouse appears to be fairly dilapidated and leaky (i.e., it was not constructed "air tight," thus, outdoor air can easily flow inwards). There were several rooms located in the warehouse. The room closest to the main entrance housed a chemical laboratory. According to the current site tenant, the chemical laboratory was operated by the owner of the Omega site until USEPA forced him to shut down the laboratory. The current site tenant plans to manufacture plastic furniture equipment in the central area of the warehouse. One of the pieces of his plastic furniture machines, which appeared to be extremely old, was placed in the middle of the warehouse. The current site tenant stated that he was planning to paint the piece of equipment and work on the wiring. He also stated that he will have approximately 11 plastic furniture making machines in operation. In addition, there were many items stored in the warehouse (clothing, children toys, mattresses, etc.). According to the current site tenant, those items were donated to him and he plans to ship them to Ukraine as a donation. Also, there was a dining area set up with a table and chairs and food items. In the back of the warehouse, there were two rooms. One of the rooms contained a sofa set, a television, and an air-conditioning unit. During our tour, the current site tenant's three teenage sons were working in the back of the warehouse. We asked if the current site tenant and his family were living in the warehouse. He stated that the warehouse was only used as storage for the last year and a half.

After visiting the main area of the warehouse, CDHS personnel visited the loading dock sump. This is the area where the highest concentration of contamination was found. The loading dock is located in the southern end of the warehouse. The entire front portion of the loading dock is opened to the outside area. The loading dock sump appeared to be a concrete box sunken into the ground. It was empty and partially covered with a metal grate. There was a winding metal staircase that reached the ceiling of the warehouse. There were many items stored in this section of the warehouse. On the shelves, there were many containers of paints and caulking materials. The current site tenant stated that he was planning to do a little repair work around the warehouse.

CDHS personnel also visited the yard of the warehouse. There was an office building near the warehouse which was closed. According to the current site tenant, the owner of the Omega site was in Ireland for a business trip. There were many pieces of large equipment stored in the yard. There were also many used computers. The current site tenant stated that he plans to salvage all usable parts of the computers and reuse them.

After CDHS personnel visited the Omega site, they visited two nearby businesses, Whittier Skateland (12520 Whittier Blvd) and Kaiser Permanente (12470 East Whittier Boulevard). This part of the visit will be covered in the Community Health Concerns section.

C. DEMOGRAPHICS AND LAND USE

The Omega site is located in a mixed industrial and residential neighborhood and located adjacent to several businesses (e.g., Pittman Inc., Medlin & Sons, Whittier Skateland). Across the street from the Omega site (north of Whittier Boulevard) is a residential area which consist of houses and apartment units. There are two municipal water suppliers for the City of Whittier: Suburban Water System and the City of Whittier (3). Suburban's groundwater well field, Bartolo Well Field, and the City of Whittier's groundwater wells are located north of the City of Whittier on Mission Mill Road in the City of Industry. Since both well fields are located approximately 3.25 miles north of the Omega site, neither Suburban's nor the City of Whittier's groundwater wells have been impacted by the contaminated groundwater plume that has migrated off the Omega site in a southwest direction. The nearest downgradient municipal drinking water, DWR #2S/11W-32G3, to the Omega site is owned by the City of Santa Fe Springs. The groundwater from DWR #2S/11W-32G3 serves the City of Santa Fe Springs. It is located 1.1 miles to the southwest of the Omega site. Current information indicates that this well has not been impacted by the contaminated groundwater emanating from the Omega site. According to USEPA, there are no known private domestic wells that are in use downgradient or in the vicinity of the Omega site (4). USEPA has indicated that they plan to conduct a well survey of all potential downgradient groundwater wells, but have not indicated a timeline for this activity (4).

Based on the 1990 census, approximately 23,805 people live in the City of Whittier (5). The ethnic makeup is 52% Hispanic; 11% Caucasian; 3% Asian or Pacific Islander; 1% African American; 0.3% American Indian, Eskimo, or Aleut; and 32% other race (5). In 1990, 29% of the total population was under the age of 18, and 12% was over the age of 65 (5).


COMMUNITY HEALTH CONCERNS

In July 1999, CDHS contacted the USEPA public participation representative for the Omega site. The USEPA representative reported that they were aware of only a few health concerns that were raised. At a small public meeting with mostly business owners held by the USEPA in June 1999, the community expressed health concerns about the presence of contaminated soil and soil gas. The plan for public participation and assessment of concerns relative to the risk assessment and possible remediation is still being developed by USEPA.

As mentioned previously, CDHS conducted a site visit in July 1999 and met with the tenant of the Omega site and some of the nearby businesses (6). The tenant stated that he did not have any health concerns and mentioned that he had been renting the space at the Omega site for over a year. He stated that he didn't have any concerns for his three teenager sons who are on site occasionally.

The manager at a skating rink, located next door to the Omega site, was concerned about the potential economic impact of health implications of the site (6). He mentioned that about 10 years ago there was some clean-up occurring at the Omega site that impacted his business. He mentioned that at this point in time neither he nor his staff had any health concerns related to the Omega site.

The medical office administrator of Kaiser Permanente, which has an office building near the Omega site, reported that she was concerned about odors and the source of the odors (6). She wanted to know if the odors were from the Omega site. She mentioned that according to an in-house engineer, the odors may be sewer gases due to the faulty plumbing design in the office building. She mentioned they had three odor episodes in the last couple of years. She stated that they had to evacuate all the people in the Kaiser building during one of the odor occurrences.

On June 1 and June 2, 2000 Sherry Chan and Primitivo Rojas canvassed the area near the Omega Site to distribute a summary flier of the PHA for the Omega site. Approximately 125 one page summaries were distributed to nearby residents and businesses. An additional 30 copies of the public comment draft of the PHA for the site were distributed. A summary of the conclusions were provided to the people receiving copies of the report. Residents and businesses were encouraged to call if they had any health concerns or comments. The people receiving the information expressed their appreciation for these outreach efforts.

Copies of the one page summary and the draft public comment PHA were also provided to the city clerk and civil engineer of the city of Sante Fe Springs. The city representatives agreed to make the information available to residents. This information would be available to the public for their review and comments. The same information was provided to the city of Whittier to the director of public works and the city clerk.

In general, people appreciated the direct effort to inform and communicate about the results of work done at the Omega site. Many of the people receiving the information were not aware of the Omega site. Primitivo Rojas provided interpretation into Spanish for ten households. The residents preferred the information in Spanish. No direct comments were received from this effort to solicit public comments.


ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

CDHS has identified three potential exposure pathways at the Omega site. The three potential exposure pathways are derived from receptor populations that may be exposed to contaminants from the "contaminant source areas" (described below). These pathways involve potential exposures to workers on the Omega site and off-site workers and residents in the vicinity of the Omega site. The contaminants are the result of past practices ( mishandling and/or improper storage of chemicals and wastes) at the Omega site. These chemicals can potentially enter buildings by the way of the soil gas and are impacting the groundwater beneath the site. In addition to the Omega site related contaminants, several other industries (e.g., Cal-Air, Leggett & Platt, Terra Pave) are located in the vicinity of the Omega site and may be a source and/or contributing to the soil gas, groundwater, and soil contamination (Appendix A: Figure 3). The existence of a public health hazard is dependent on the magnitude of contamination in the various environmental media and not the source.

The following conditions were used to select contaminants for further evaluation: 1) concentrations of contaminants on and off site; 2) field data quality, laboratory data quality, and sample design; 3) comparison of on-site and off-site concentrations with environmental comparison values; and 4) community health concerns. Comparison values, developed by ATSDR and USEPA, were used to select contaminants for further evaluation and are listed in a glossary in Appendix B. The evaluation of the health effects associated with exposures to contaminants is accomplished by comparing the level of contaminants to "comparison values." Although off-site contamination may not be the responsibility of the Omega responsible parties, the comparison values are determined by ATSDR and other agencies to allow for a general screening of contaminants found at sites under investigation. These comparison values allow an investigator to quickly sort the contaminants into groups that are either not likely to cause health effects, or contaminants that should be evaluated further. Contaminants that receive further evaluation exist at concentrations that exceed the comparison values, and are called "contaminants of concern."

A. ON-SITE CONTAMINATION

SUMMARY OF THE SOIL GAS INVESTIGATION

Between November 13 and 17, 1995, England & Hargis conducted a soil gas investigation at the Omega site (1). Soil gas samples were collected from 30 locations, SG-1 to SG-30 (Appendix A: Figure 4) at six and twelve feet below ground surface (bgs). The soil gas samples were analyzed for the following contaminants: Freon-12, Freon-11, dichloromethane, trans-1,2-dichloroethene, 1,1-dichloroethane, cis-1,2-dichloroethene, chloroform, 1,1,1-trichloroethane (TCA), 1,2-dichloroethane (DCA), trichloroethene (TCE), tetrachloroethylene (PCE), 1,1-dichloroethene (DCE), Freon-113, benzene, toluene, ethyl benzene, and m,p,o-xylenes. At sampling location SG-10 (location of the former concrete loading dock sump), a soil gas sample was not collected at 12 feet bgs due to the inability of the probe to penetrate the soil. Thus, an additional soil gas sampling location, SG-31, was added approximately five feet southwest of SG-10. At SG-31, a soil gas sample was collected at 3.5 feet bgs. Also, three deeper soil gas samples were collected from locations SG-4 (16.7 feet bgs), SG-16 (24 feet bgs), and SG-19 (24 feet bgs).

Based on the soil gas investigation, VOCs were detected in 56 of the 63 soil gas samples which represented 28 of the 31 locations sampled (Appendix A: Figure 4). The analytical results of the soil gas investigation are summarized in Table 1, Appendix C. The most prevalent VOCs detected in the soil gas at the Omega site and at the highest concentrations were Freon 113, Freon 11, 1,1,1-TCA and PCE (1).

During drilling operations by Camp, Dresser, and McKee in the summer of 1999 six soil gas samples were collected at various depths and analyzed for VOCs at location OW-1b (7). PCE, TCE, 1,1,1-TCA, 1,1-DCE, chloroform, Freon 11 and Freon 113 were detected in these samples. PCE concentrations generally increased with depth and ranged from 150,000 parts per billion (ppb) at 10 feet bgs to 6,100,000 ppb at 60 bgs (7).

SUMMARY OF THE SUBSURFACE SOIL INVESTIGATION

Between December 11 and 14, 1995, England and Hargis, contractors for the responsible parties, conducted shallow subsurface soil sampling on the Omega site (1). Soil samples were collected from fifteen shallow soil boring locations, SB-1 to SB-15. Soil samples were collected from approximately 1 foot and 6 feet bgs at each of the soil boring locations (Appendix A: Figure 5). The soil samples were analyzed for metals, VOCs, semi-volatile organic compounds (SVOCs), and chlorinated pesticides (Appendix C: Tables 4 to 7). Based on the shallow subsurface soil sampling investigation, several contaminants were detected above ATSDR's health comparison values (HCVs) or USEPA's Preliminary Remediation Goals (PRGs). Metals detected above ATSDR's HCV or USEPA's PRGs include: antimony, arsenic, barium, chromium, nickel, and vanadium. VOCs detected above ATSDR's HCV or USEPA's PRGs include: 1,1-DCE, methylene chloride, TCE, PCE and toluene. The highest concentrations of VOCs were detected in soil samples collected and analyzed from SB-9, located beneath the loading dock (1). The only SVOC detected above ATSDR's HCV is benzo(a)pyrene. Aroclor 1254 was the only PCB detected above ATSDR's HCV. There were no chlorinated pesticides detected above health comparison values.

In addition to the shallow subsurface soil samples collected from 1 foot and 6 feet bgs, seven deep subsurface soil samples (C1, C2, C3, C7, C7A, H1, H2 and H4) were collected on the Omega site (Appendix A: Figure 5). Soil samples were collected at depths ranging from 15 to 75 feet bgs and 55 to 110 feet bgs from C-series and H-series deep subsurface soil borings, respectively. The soil samples were analyzed for VOCs (Appendix C: Table 5). PCE was detected in the deep subsurface soil samples above ATSDR's HCV. The maximum concentration of contaminants in the subsurface soil are summarized in Table 2, Appendix C.

The soil gas data that were collected add insight into the nature of the contamination at the Omega site. Soil gas data are useful when evaluating the source of in-building contamination and/or the potential for soil gas migration into buildings. For these reasons, the soil gas data can not be directly used for health risk assessments, but they can be used to estimate the concentrations of contaminants in the in-building air with the use of air models and they may help pinpoint any future indoor air sampling efforts.

During drilling operations by Camp, Dresser, and McKee in the summer of 1999 soil samples were collected at locations OW-1b, OW-2 and OW-3 and analyzed for VOCs (7). PCE was the compound detected most frequently, ranging in concentration from 4.7 micrograms per kilogram (ug/kg) at 120 feet bgs to 3,300 ug/kg at 70 feet bgs at location OW-1b (7).

SUMMARY OF THE SURFACE SOIL INVESTIGATION

The Omega site is paved with concrete so there is no surface soil to sample.

SUMMARY OF THE GROUNDWATER INVESTIGATION

Between January 29 and February 1, 1996, England and Hargis, contractors for the responsible parties, conducted groundwater sampling for the Omega site (1). Groundwater samples were collected from four on-site locations, H-1 through H-4 (Appendix A: Figure 6). Nine groundwater samples were collected from depths ranging from 60 to 70 feet bgs and analyzed for VOCs (Appendix C: Table 5). Contaminants in the groundwater detected above ATSDR's HCV or USEPA's PRG include: acetone, benzene, chloroform, 1,1-DCE, 1,2-DCA, methylene chloride, PCE, toluene, TCE, 1,1,1-TCA and trichlorofluoromethane. Freon 113 was detected in the groundwater samples ranging from 2,000 to 6,400 microgram per liter (ug/L). These concentrations are well below ATSDR's reference dose based media evaluation guide (RMEG) for children of 30,000 ug/L. However, these levels are above California's safe drinking water standard of 1,200 ug/L.

During May and June 1996, groundwater samples were collected from deep soil boring B-4 and monitoring well, OW-1, and analyzed for VOCs(Appendix A: Figure 6; Appendix C: Table 5). The groundwater samples were collected from depths of approximately 75 feet bgs. Contaminants in the groundwater detected above ATSDR's HCV or USEPA's PRG include: chloroform, 1,1-DCE, 1,2-DCA, methylene chloride, PCE, TCE and 1,1,1-TCA . The maximum concentrations of groundwater contamination are summarized in Table 3, Appendix C.

B. OFF-SITE CONTAMINATION

SUMMARY OF GROUNDWATER INVESTIGATIONS

Between July 15 and 20, 1996, England and Hargis, contractors for the responsible parties, conducted groundwater sampling southwest of the Omega site to assess the lateral extent of the groundwater contamination (1). Groundwater samples were collected from eight off-site locations, H-6 through H-13(Appendix A: Figure 6). Groundwater well H-13 is located approximately 1,500 feet southwest and downgradient of the Omega site. This well is the furthest well from the Omega site. The maximum concentrations of groundwater contamination are summarized in Table 3, Appendix C. Groundwater samples were collected from depths ranging from 72 to 122 feet bgs and analyzed for VOCs (Table 5). Contaminants in the groundwater detected above ATSDR's HCV or USEPA's PRG include: acetone, benzene, chloroform, 1,1-DCE, 1,2-DCA, methylene chloride, PCE, toluene, TCE, 1,1,1-TCA and trichlorofluoromethane. Freon 113 was detected in the groundwater samples ranging from 700 to 7,500 ug/L. These concentrations are well below ATSDR's reference dose based media evaluation guide (RMEG) for children of 30,000 ug/L. However, some of these samples are above California's safe drinking water standard of 1,200 ug/L.

Between June 15 and July 2, 1999, Camp Dresser and McKee conducted additional groundwater sampling at the Omega site (7). Groundwater samples were collected from three newly developed wells (OW-1b, OW-2, OW-3) and one existing well (OW-1) and analyzed for VOCs. PCE, TCE, 1,1,1-trichloroethane, 1,1-DCE, Freon 113 and Freon 11 were detected in all four groundwater wells. Tetrachloroethene, TCE and 1,1-DCE were above health comparison values in all four groundwater wells. The highest concentrations were detected in OW-1 with 1,200 ppb 1,1-DCE, 23,300 ppb PCE and 1,300 ppb TCE. Well OW-1 is screened between 62.5 and 77.5 feet. The deeper OW-1b is screened from 110 to 120 feet bgs. Samples collected from OW-1b had detections of VOCs that were generally two orders of magnitude lower than concentrations detected in OW-1. This information suggests subsurface conditions may be inhibiting the vertical migration of Omega groundwater contamination. However, based on current information, it does not appear that the full vertical extent of the groundwater contamination has been identified.


LIMITATIONS WITH THE INVESTIGATIONS DESCRIBED IN THIS PUBLIC HEALTH ASSESSMENT

Limitations in the scope of an investigation and/or lack of data (data gaps) can be a source of uncertainty associated with any scientific investigation. Limitations of this PHA are related to data gaps in our understanding of soil gases at the site and information about the downgradient extent of the groundwater plume eminating from the Omega site. Most of these limitations should be resolved because investigations of the Omega site by USEPA are addressing these issues. In particular, the leading edge of the groundwater contamination from Omega has not been identified yet. USEPA is currently installing sentinel wells downgradient of known contaminated areas. These wells should help track or locate the groundwater contamination from the Omega site.

It is the view of the authors that the limitations and data gaps do not compromise the conclusions. However, a variety of uncertainties must be taken into account when considering the strength of the conclusions, and making recommendations. The recommendations presented later in this document in the Public Health Recommendation and Action section are aimed at addressing the limitations described below.


PATHWAYS ANALYSES

This section addresses the pathways by which people in the area surrounding the site are exposed or may have been exposed to contaminants at, or migrating from, the site. If it is determined that exposure to chemicals not necessarily related to the site is also of concern, that exposure is evaluated as well.

When a chemical is released into the environment, the release does not always lead to exposure. Exposure only occurs when a chemical comes into contact with people and enters the body. In order for a chemical to pose a human health risk, a complete exposure pathway must exist.

A completed exposure pathway consists of five elements: 1) a source and a mechanism of chemical release to the environment; 2) a contaminated environmental medium such as air, soil, or water; 3) point where someone contacts the contaminated medium (known as the exposure point); 4) an exposure route such as, inhalation, dermal absorption, or ingestion; and 5) the person or people exposed (8).

Exposure pathways are classified as either completed, potential, or eliminated. In completed exposure pathways, all five elements exist. Potential exposure pathways are either: 1) not currently complete, but could become complete in the future, or 2) are indeterminate due to lack of information. Pathways are eliminated from further assessment if one or more element of exposure pathways is missing and is never likely to exist.

A time frame given for each pathway indicates whether the exposure occurred in the past, is occurring, or will occur in the future. For example, a completed pathway with only a past time frame indicates that exposure did occur in the past, but exposure is not occurring now and is not likely to occur in the future. The following discussions describe how people have been or may be exposed to contaminants. The health implications of the completed exposure pathways are discussed in the Public Health Implications section.

A. COMPLETED EXPOSURE PATHWAY

Based on the limited data, there are no completed exposure pathways.

B. POTENTIAL EXPOSURE PATHWAYS

Potential Future Exposure to Soil Contaminated with VOCs - On-Site Workers

Based on the subsurface soil investigations by England and Hargis and CDM, elevated concentrations of VOCs were detected in the subsurface soil at the Omega site. However, exposures to on-site soils would need to be of a chronic exposure period to see health effects. Additionally, the Omega site is paved with concrete and therefore it is unlikely that exposure will occur. It is possible that future construction at the Omega site may lead to contact with contaminated soils. However, these exposures would likely be one to two years of exposure and therefore are not likely to result in any adverse health effects.

Potential Current and Future Exposure to Soil Gas Contaminated with VOCs-Workers on the Omega Site

Based on the soil gas investigation conducted by England and Hargis, high concentrations of VOCs were detected in soil gas in several soil gas monitoring locations within the Omega site. Although it is not possible to directly assess the health impact based on the soil gas concentrations, these concentrations do suggest potential in-building air health impacts and the need for in-building air monitoring (Appendix C: Table 8). Because the warehouse, which has been leased for manufacturing purposes, is located on the Omega site potential soil gas migration into the in-building air may pose a health concern to workers in the warehouse. A Health Consultation will be issued to reflect any additional information that changes the conclusions of this PHA.

Potential Current and Future Exposure to Soil Gas Contaminated with VOCs-Residents and Workers in the Vicinity of the Omega Site

Based on the soil gas investigation conducted by England and Hargis, elevated concentrations of VOCs were detected in soil gas in several locations within, and at the boundary of, the Omega site. Although it is not possible to directly assess the health impact based on the soil gas concentrations, these concentrations suggest the potential for exposure to soil gas VOCs does exist. Because gases are very mobile, it is difficult to determine where soil gases will travel. Therefore, efforts to determine the potential health impacts from soil gases from the Omega site should incorporate ambient air monitoring at the boundary of the Omega site and in buildings on the Omega site (Appendix C: Table 8). If these efforts are non-detect for the COCs or are detected below health comparison values, then no further action should be necessary. However, if boundary and/or indoor air concentrations are of health concern, additional actions would need to be taken. A Health Consultation will be issued to reflect any additional information that changes the conclusions of this PHA.

Potential Future Exposure to Groundwater Contaminated with VOCs Via Municipal Water Systems- Citizens of the City of Santa Fe Springs

Based on the groundwater investigations conducted by England and Hargis, and Camp, Dresser and McKee (CDM), VOCs were detected in the groundwater on and off site. The contaminated groundwater plume migrating off the Omega site does not appear to have impacted the nearest operating downgradient municipal groundwater well, DWR#2S/11W-32G3, which belongs to and services the City of Santa Fe Springs (Appendix C: Table 8). Municipal water supply wells are routinely sampled for VOCs and a variety of other potential contaminants. Currently, the USEPA is taking actions to prevent the contaminated groundwater plume from impacting this municipal well. USEPA plans to identify the sources and areas of groundwater contamination and then identify and evaluate the cleanup options for the groundwater contamination problems (4). This information will be summarized in a Remedial Investigation/Feasibility Study (RI/FS) document (4). Remedial Investigation/Feasibility Study activities are currently under way. The drinking water from municipal well, DWR #02/11W-30R3S, is sampled on a regular basis to insure that the quality of the water meets California drinking water standards (3). However, because the ingestion and/or usage of contaminated groundwater may be a potential future health concern, we are evaluating the potential future health impact to citizens of the City of Santa Fe Springs.

Potential Past, Current, and Future Exposure to Groundwater Contaminated with VOCs Via Private Groundwater Wells - Off-Site Workers and Residents in the Vicinity of the Omega Site

Based on the groundwater investigations conducted by England and Hargis, and CDM, high concentrations of VOCs were detected in the groundwater on-site and off-site. According to the USEPA, there are no known private domestic groundwater water wells that are in use downgradient or in the vicinity of the Omega site (Appendix C: Table 8). The USEPA has stated that they plan to conduct a well survey of all the potential downgradient groundwater wells to confirm this (4). CDHS and ATSDR recommend that this effort be completed in the near future to ensure that there are no private wells extracting contaminated groundwater for potable uses. Thus, the ingestion and/or usage of contaminated groundwater may be a potential health concern.

C. ELIMINATED EXPOSURE PATHWAYS

Past, Current, and Future Exposure to the Groundwater Contaminated with VOCs - Via City of Whittier Municipal Water Systems - Workers on the Omega Site, Residents, and Workers in the Vicinity of the Omega Site

Based on the groundwater investigation conducted by England and Hargis, and CDM, elevated concentrations of VOCs were detected in the groundwater on-site and off site. The contaminated groundwater plume has not impacted any municipal groundwater wells serving the City of Whittier, therefore this pathway has been eliminated from further evaluation (Appendix C: Table 9). The groundwater wells belonging to the two municipal water suppliers for the City of Whittier are located in the City of Industry which is approximately 3.25 north of the City of Whittier. Since the contaminated groundwater plume is moving in a southwest direction, groundwater contamination at the Omega site does not and will not likely have any impact to the City of Whittier's drinking water system.


PUBLIC HEALTH IMPLICATIONS

A. TOXICOLOGICAL EVALUATION

In evaluating health effects, several factors determine whether harmful effects will occur and the type and severity of those health effects. These factors include the dose (how much), the duration (how long), the route by which people are exposed (breathing, eating, drinking, or skin contact), the other contaminants to which they may be exposed, and their individual characteristics such as age, sex, nutrition, family traits, life style and state of health.

In order to determine whether adverse health effects are possible as a result of exposure to a contaminant, an exposure dose must be estimated for each pathway. This exposure dose can then be compared with appropriate toxicity values in order to evaluate the likelihood of adverse health effects occurring. Toxicity values used to evaluate non-cancer adverse health effects include ATSDR's Minimal Risk Level (MRL) and EPA's Reference Dose (RfD) for ingestion and Reference Concentration (RfC) for inhalation. These values are estimates of daily human exposure to a contaminant below which non-cancer, adverse health effects are unlikely to occur. Please see the Appendix B - Glossary for an in-depth discussion of the toxicity values.

The National Toxicology Program (NTP), the International Agency for Research on Cancer (IARC), and USEPA have reviewed available information from human and/or animal studies to determine whether certain chemicals are likely to cause cancer in humans. The potential for cancer to occur in an individual or a population is evaluated by estimating the probability of an individual developing cancer over a lifetime as the result of the exposure. EPA has developed cancer slope factor values for many carcinogens. A cancer slope factor is an estimate of a chemical's potential for causing cancer. Please see the Appendix B - Glossary for an in-depth discussion of the toxicity values for cancer.

In this section, we have included an analysis of the potential health impact, both non-cancer and cancer, to on-site and off-site workers, and near-by residents for groundwater and subsurface soil pathways. Also, general discussion about exposures to the contaminants detected in the subsurface soil and the groundwater is included in the Appendix D - Toxicological Profiles for Chemicals.

Potential Current and Future Exposure to Soil Gas Contaminated with VOCs - Workers on the Omega Site and Workers and Residents in the Vicinity of the Omega Site

Based on the soil gas investigations, VOCs were detected in the majority of locations sampled on the Omega site. The most prevalent and highest concentrations of VOCs include: Freon 113, Freon 11, 1,1,1-TCA and PCE (Appendix C: Tables 1 & 2). Based on the available data, we know that there are high concentrations of VOCs in the soil gas within the boundaries of the Omega site.

Using the Karimi model, which is a simple diffusion-based screening model, CDHS estimated the in-building air concentrations of PCE that may be caused by soil gases. The Karimi model uses a number of chemical and physical constants in calculating concentrations of gases in a building, based on soil gas data. This model may underestimate concentrations in a building resulting from convectional forces caused by heating the building interior and creating a suction effect on the soil gases causing them to enter the buildings. Heating the building will pull vapors up into the building from soils beneath the building footprint. The Karimi model also incorporates measured or investigated values that are site specific. In the case of the Omega site, CDHS used average PCE concentrations detected in soil gas from sample locations beneath the site building footprint. Other contaminants detected in soil gases were not incorporated into this model because chemical-specific vapor phase diffusion coefficients were not available for the contaminants of concern. The Karimi model predicted a significant concentration of PCE would diffuse into the site building. The model predicted the concentrations of PCE in the site building to be 7,930 ppb (ug/m3). This is significantly greater than the chronic EMEG for PCE in air of 40 ppb (ug/m3). See Appendix E for a summary of assumptions used in the Karimi Model. Based on our estimates, it appears that the contaminants in the soil gas may pose an in-building air concern. However, to determine if the VOC- contaminated soil gas has migrated into the buildings at concentrations that pose a health concern, in-building air monitoring is needed.

Elevated concentrations of VOCs were detected in the soil gas collected from several locations at the boundary of the Omega site. This may pose a health concern because soil gas contaminants can migrate and escape from the soil surface. Once liberated at the soil surface, the contaminants can enter buildings. Because of their construction characteristics, certain buildings tend to "trap" or "pull" soil gas contaminants into the structure. In this manner, soil gas contaminants can enter buildings, and people using the building can inhale the contaminants. While soil gas can be an important source of in-building air contaminants, it is only one of several contributors to the total air contaminants found inside a building. Other sources of indoor air contaminants include the chemicals contained in the outdoor air and the chemicals released into the building by the building components and contents. Furthermore, products (i.e., chemicals, cleaning solutions) used in the daily processes of tenant operations can contribute to the concentrations of contaminants in the indoor air.

Based on the proximity of the skating rink, immediately to the southwest of the Omega site, and the concentrations of soil gas contaminants detected at the site, CDHS has considered the potential for VOCs in soil gas to migrate towards the skating rink and the potential for those contaminants to migrate into the building through the foundation. Based on estimates for PCE migration into the Omega site buildings, CDHS believes that the migration of soil gas contaminants into off-site buildings is a possibility. However, the distribution of soil gas concentrations, particularly for PCE, at the Omega site appear to be localized near the former sump area in the southwestern portion of the site (Appendix A: Figure 7). This suggests that the likelihood of significant concentrations reaching the skating rink is remote. Nonetheless, the possibility does exist that soil gas contaminants from the Omega site could impact indoor air at the skating rink and, potentially, other off-site locations. Soil gas contaminants from the Omega site that migrate to the skating rink could affect the health of workers and visitors to the skating rink, most specifically children. At this time this pathway is considered a potentially completed pathway, due to limited data. In order to fully assess this pathway, ambient air monitoring data must be collected at least for the Omega site. Further ambient air monitoring may be needed if it is determined that air concentrations at the Omega site are of a health concern. If ambient air concentrations at Omega are not a health concern, then it is highly unlikely that soil gas contaminants will adversely impact the skating rink or other off-site locations.

The soil gas investigation provided valuable information concerning the level of VOCs in the soil. Additional information is necessary in order to fully assess the impact of the high level of VOCs in the soil gas beneath the Omega site. Specifically, an in-building air monitoring investigation is needed to determine if the soil gas has migrated into the on-site buildings and potentially to off-site buildings and businesses.

On-site Workers on the Omega Site - Potential Future Exposure to Soil Contaminated with VOCs

Based on the subsurface soil investigations by England and Hargis and CDM, elevated concentrations of VOCs were detected in the subsurface soil at the Omega site. However, exposures to on-site soils would need to be of a chronic exposure period to see health effects. Additionally, the Omega site is paved with concrete and therefore it is unlikely that exposure will occur. It is possible that future construction at the Omega site may lead to contact with contaminated soils. However, these exposures would likely be one to two years of exposure and therefore are not likely to result in any adverse health effects.

In order to estimate conservative non-cancer and cancer doses, we assumed that the concrete pavement was removed from the Omega site for a construction project that took two years to complete. CDHS estimated non-cancer ingestion doses for workers (i.e., PCE [0.000395 milligrams per kilograms per day (mg/kg/day)], antimony [0.0000055 mg/kg/day], arsenic [0.0000027 mg/kg/day], barium [0.000070 mg/kg/day], chromium [0.000064 mg/kg/day], nickel [0.0000167 mg/kg/day], and vanadium [0.000022 mg/kg/day]) based on the highest level of each contaminant detected in the subsurface soil. None of the adult non-cancer ingestion doses exceed ATSDR's MRLs or USEPA's RfDs, thus, non-cancer health effects are not expected for workers (i.e., namely, construction workers) who spend 10 hours/day, 5 days/week for a two-year long construction project on the Omega site.

Polycyclic aromatic hydrocarbons (PAHs) were detected in only one soil sample (SB-15 at 1.7' bgs) (1). Benzo(a)pyrene (1.6 parts per million (ppm)) was the only PAH detected that was above USEPA's preliminary remediation goals (PRGs), which are protective of public health. Because the site is paved, it is currently unlikely that workers would be exposed to these levels at the Omega site.

CDHS estimated the total increased lifetime excess cancer risk, 4 x 10-7, for the three contaminants (i.e., PCE, benzo(a)pyrene, and arsenic) that are carcinogens via the ingestion route. This is considered to be a no apparent increased cancer risk to workers that may be exposed to contaminants in the subsurface soil during a construction and/or redevelopment project in the future.

We did not estimate non-cancer and cancer doses for the following contaminants: 1,1-DCE, methylene chloride, TCE, and toluene because these contaminants were detected in subsurface soil that was located in the loading dock sump which has been excavated and removed off-site. Thus, there are no potential current and/or future exposures to these contaminants.

Off-site Workers and Residents in the Vicinity of the Omega Site - Potential Exposure to Contaminants in the Groundwater Obtained from Private Wells

In order to estimate conservative non-cancer and cancer doses, we assumed that the concentrations of contaminants measured on-site could move off-site and eventually impact downgradient groundwater wells (i.e., private wells which may exist in the vicinity of the Omega site and one of the municipal wells, DWR #2S/11W-32G3, owned by the City of Santa Fe Springs). We assumed that a person ingested two liters per day of the contaminated groundwater for 30 years. This is being evaluated as a possible potential future scenario that could only occur if no remedial action of the contaminated groundwater is taken. This may be an overestimation of the toxicological evaluation for this future exposure pathway because as the contaminated groundwater plume moves, the plume will become more spread out which would result in the dilution of the contaminant concentrations. Additionally, there would probably be some degradation of the chemicals in the groundwater, thus, further lowering the concentrations of contaminants that would possibly ever reach the groundwater wells.

CDHS estimated non-cancer ingestion doses for adults (i.e., acetone [0.82 mg/kg/day], benzene [0.0021 mg/kg/day], chloroform [0.63 mg/kg/day], 1,1-DCE [0.19 mg/kg/day], 1,2-DCA [0.27 mg/kg/day], methylene chloride [4.11 mg/kg/day], PCE [2.36 mg/kg/day], toluene [0.080 mg/kg/day], TCE [0.17 mg/kg/day], 1,1,1-TCA [0.38 mg/kg/day], and trichlorofluoromethane [0.12 mg/kg/day]) based on the highest level of each contaminant detected in the groundwater. Five of the adult non-cancer doses (chloroform, 1,1-DCE, 1,2-DCA, methylene chloride, and PCE) exceed ATSDR's MRLs or USEPA's Reference Dose (RfD, Appendix B: Glossary), thus, requiring further evaluation if the contaminants measured in the groundwater on-site were detected in private groundwater wells (which may or may not exist in the vicinity of the Omega site) or ever reach the City of Santa Fe Spring's municipal groundwater well (i.e., DWR #2S/11W-32G3).

CDHS also estimated non-cancer ingestion doses for children (i.e., acetone [1.8 mg/kg/day], benzene [0.00449 mg/kg/day], chloroform [1.38 mg/kg/day], 1,1-DCE [0.414 mg/kg/day], 1,2-DCA [0.599 mg/kg/day], methylene chloride [8.99 mg/kg/day], PCE [5.15 mg/kg/day], toluene [0.174 mg/kg/day], TCE [0.378 mg/kg/day], 1,1,1-TCA [0.839 mg/kg/day], and trichlorofluoromethane [0.258 mg/kg/day]) based on the highest level of each contaminant detected in the groundwater. All of the child non-cancer doses (benzene, chloroform, 1,1-DCE, 1,2-DCA, methylene chloride, PCE, TCE, and 1,1,1-TCA) exceed ATSDR's MRLs or USEPA's RfDs, thus, non-cancer health effects could occur to children if the contaminants measured in the groundwater on-site were detected in private groundwater wells.

CDHS estimated the total increased lifetime excess cancer risk, 7.4 x 10-2, for the following contaminants (i.e., benzene, chloroform, 1,1-DCE, 1,2-DCA, and methylene chloride) which are considered to be carcinogenic. This is considered a high increased cancer risk. This high increased cancer risk would be predicted if the contaminants in the groundwater on-site ever impacted these groundwater wells.

B. COMMUNITY HEALTH CONCERNS EVALUATION

Q: Are there any health implications from the contaminated soil or soil gas?
A: The Omega site is paved with concrete. There are no health impacts because no one is exposed to the contaminated soil. Based on the limited available data, the inhalation of soil gas is a potential health concern.
Q: Can odors that have been smelled at Kaiser Permanente be coming from the Omega Site and can they be harmful?
A: Based on the limited data it is difficult to assess whether there is off-site migration of soil gas from the Omega site. CDHS has recommended that USEPA conduct an ambient air survey around the border of the Omega site to determine the health risk to potential soil gas migration. According to USEPA, the source of the odor problem may be from a metal fence galvanizing facility located on Putnam Street (4). CDHS has been in contact with the South Coast Air Quality Management District (SCAQMD) regarding this matter (personal communication with Lynn Brown of SCAQMD on 4/25/01). According to Ms. Lynn Brown project manager for the Merchant Metals facility located at 12482 East Putnam Drive in Whittier, the facility is currently in compliance with all applicable air quality regulations. Ms. Brown indicated that SCAQMD is in the process of determining what chemicals are causing the odor problems and working with Merchant Metals to resolve the odor problems.


ATSDR CHILD HEALTH INITIATIVE

ATSDR recognizes that infants and children may be more sensitive to exposures, depending on substance and the exposure situation, than adults in communities with contamination of their water, soil, air, and/or food. This sensitivity is a result of several factors: 1) Children may have greater exposures to environmental toxicants than adults because pound for pound of body weight, children drink more water, eat more food, and breathe more air than adults; 2) Children play outdoors close to the ground which increases their exposure to toxicants in dust, soil, surface water, and in the ambient air; 3) Children have a tendency to stick their hands in their mouths while playing without washing their hands, thus, they may come into contact with, and ingest, potentially contaminated soil particles at higher rates than adults (also, some children possess a behavior trait known as "pica" which causes them to ingest non-food items, such as soil); 4) Children are shorter than adults, which means they can breathe dust, soil, and any vapors close to the ground; 5) Children's bodies are rapidly growing and developing; thus, they can sustain permanent damage if toxic exposures occur during critical growth stages; and 6) Children and teenagers may disregard no trespassing signs and wander onto restricted locations. Because children depend completely on adults for risk identification and management decisions, ATSDR is committed to evaluating their special interests at sites such as the Omega site as part of the ATSDR Child Health Initiative.

CDHS has attempted to identify places (e.g., parks, schools, recreational facilities) in the vicinity of the Omega site where children spend time (i.e., live, play, or go to school). The location closest to the Omega site where children may spend time is at a skating rink that abuts the Omega site to the south (less than 100 feet away). For the reasons described previously, on-site soil and groundwater do not represent a public health hazard for children at this time. However, soil gas migration from the Omega site may pose a health concern for children due to the proximity of the skating rink.CDHS plans to revisit the Omega site and issue a Health Consultation if the additional environmental data show that the Omega site poses a public health hazard. Off-site groundwater contamination is a potential future exposure source for children if contamination from the Omega site gets into the municipal water supply.


CONCLUSIONS

Based on the information reviewed, the California Department of Health Services (CDHS) and the Agency for Toxic Substances and Disease Registry (ATSDR) conclude that the Omega site poses an indeterminate public health hazard to on-site workers and residents and off-site workers in the vicinity of the Omega site.

Based on the limited data, CDHS determined that there are no completed exposure pathways. CDHS identified two potential exposure pathways: breathing soil gas, and drinking groundwater.

According to the limited soil gas data collected by England and Hargis and CDM, high concentrations of VOCs were detected in the soil gas in several soil gas monitoring locations within the Omega site. Although it is not possible to directly assess the health impacts based on the soil gas concentrations, they do suggest potential in-building air health concerns to individuals both on and, in the vicinity of, the site. Thus, the soil gas poses a potential public health concern.

Based on the groundwater investigations conducted by England and Hargis, and CDM, high concentrations of VOCs were detected in the groundwater on- and off-site. To date, the contaminated groundwater plume migrating off the Omega site has not impacted the nearest operating downgradient municipal groundwater well which is owned by the City of Santa Fe Springs. This municipal well serves the citizens of the City of Santa Fe Springs. Currently, USEPA is installing sentinel wells downgradient of the Omega site in an attempt to prevent this plume from impacting the City of Santa Fe Springs' municipal well. USEPA has plans to implement additional RI/FS activities in the summer of 2001. However, if USEPA's efforts to treat contamination from the Omega site are not successful, the groundwater plume could impact the municipal well and pose a potential health impact to the citizens of the City of Santa Fe Springs.

According to the USEPA, there are no known private domestic groundwater wells that are in use downgradient or in the vicinity of the Omega site. USEPA has indicated that they plan to conduct a well survey to confirm this. Therefore, the ingestion and/or usage of contaminated groundwater may be a potential exposure pathway. Since CDHS has determined that the contaminated groundwater may pose a future public health concern to individuals exposed to contaminated groundwater, we estimated both non-cancer and cancer doses. Several of the estimated non-cancer doses exceed ATSDR's MRLs, thus, non-cancer health effects could occur if the contaminants measured in the groundwater on-site were detected in the private groundwater wells or in the City of Santa Fe Spring's municipal well. Also, CDHS estimated the cancer risk for the contaminants that are carcinogens via the ingestion route and determined that a high increased cancer risk is predicted if the contaminants in the groundwater on-site ever impacted these groundwater wells.

The contaminated groundwater from the Omega site does not pose a past, current, or future health concern to the citizens of the City of Whittier. The municipal groundwater wells that belong to the two municipal water suppliers for the City of Whittier are located in the City of Industry, which is located approximately 3.25 miles north of the City of Whittier. Since the contaminated groundwater plume is migrating off the Omega site in a southwesterly direction, it has and will not likely have any impact to the City of Whittier's municipal water supply.

Based on the available environmental data reviewed and evaluated, the Omega site poses an indeterminate public health hazard. Currently, USEPA is providing environmental oversight and remediation at the Omega site, CDHS believes that if these remedial activities are successful the site will not impact the health of individuals living and working in the vicinity of the Omega site.


PUBLIC HEALTH RECOMMENDATIONS AND ACTIONS

A. Actions Completed

  1. England and Hargis, contractors for the responsible parties, have completed the Phase I investigation which involved the removal of drums, containers, and debris from the Omega site.


  2. England and Hargis, contractors for the responsible parties, have completed the Phase II investigation which involved the collection and analysis of soil gas, soil, and groundwater on the Omega site.


  3. CDM completed a draft Phase 1a Pre-design Field Investigation Report for the Omega site.

B. Actions Planned

  1. USEPA plansto perform a risk assessment for the Omega site.


  2. USEPA plans to conduct an updated well survey of all potential groundwater wells downgradient of the Omega site.


  3. USEPA is in the process of installing and developing sentinel wells downgradient of the Omega site to track the groundwater contamination from the Omega site.


  4. USEPA plans to conduct a remedial investigation and feasibility study for the Omega facility.


  5. USEPA plans to conduct a remedial investigation and feasibility study for areas downgradient of the Omega site.

C. Recommendation for Further Actions

  1. CDHS recommends that indoor air monitoring for on-site buildings at the Omega site be conducted by USEPA to determine air levels of site-related contaminants. CDHS will evaluate this data to assess the public health implications of this pathway.


  2. CDHS recommends that USEPA install soil gas probes, at various depths below ground surface, along the perimeter of the Omega site to determine the extent of soil gas migration in the horizontal direction.


  3. CDHS recommends that municipal well, DWR #2S/11W-32G3, which belongs to and services the City of Santa Fe Springs, be monitored regularly by the California Department of Drinking Water to ensure that Omega site contaminants do not impact this municipal groundwater well.


  4. CDHS recommends that USEPA undertake a private well survey of the area downgradient of the site to determine if individuals or businesses are using private well water for potable purposes.


  5. CDHS recommends continued downgradient groundwater monitoring to ensure contamination from the Omega site does not impact municipal water supply wells.


  6. CDHS recommends that USEPA make efforts to contain and remediate groundwater contamination from the Omega site and to determine the vertical and horizontal extent of contamination.

PREPARERS OF REPORT

ENVIRONMENTAL AND HEALTH EFFECTS ASSESSORS

Gregory E. Braun
Research Scientist
Impact Assessment, Inc., Consultant to
California Department of Health Services,
Environmental Health Investigations Branch

Sherry Chan, M.P.H.
Industrial Hygienist
Impact Assessment, Inc., Consultant to
California Department of Health Services,
Environmental Health Investigations Branch

Marilyn C. Underwood, Ph.D.
Staff Toxicologist
California Department of Health Services,
Environmental Health Investigations Branch

COMMUNITY RELATIONS COORDINATOR

Primitivo Rojas, M.P.H.
Community Health Educator
California Department of Health Services,
Environmental Health Investigations Branch

ATSDR REGIONAL REPRESENTATIVES

William Nelson, M.S.
Dan Strausbaugh, M.P.H.
Gwen Eng
Regional Services, Region IX
Office of Regional Operations

ATSDR TECHNICAL PROJECT OFFICER

Tammie McRae, M.S.
Environmental Health Scientist
Agency for Toxic Substances and Disease Registry


CERTIFICATION

This Omega Chemical Public Health Assessment was prepared by the California Department of Health Services under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the public health assessment was begun.


Tammie McRae, M.S.
Technical Project Officer, SPS, SSAB, DHAC


The Division of Health Assessment and Consultation, ATSDR, has reviewed this public health assessment and concurs with the findings.


Richard Gillig
Chief, State Program Section, DHAC, ATSDR


REFERENCES

  1. England & Associates and Hargis & Associates, Inc., Phase II Close Out Report. Volume I of II. Prepared for Omega Chemical Site PRP Organized Group. 10/1/96.
  2. United States Environmental Protection Agency. National Priority List-Omega Chemical Corporation 9/98.
  3. Phone Correspondence Concerning the Municipal Water Supply for the City of Whittier between Abbas Amir, Associate Sanitary Engineer, with the California Department of Health Services-Drinking Water and Environmental Health, Field Operation Branch-Metro and Sherry Chan, Research Specialist, with the California Department of Health Services-Environmental Health Investigation Branch. 9/24/99 and 12/10/99.
  4. United States Environmental Protection Agency. EPA's Comments on the September 29, 1999 Initial Release Public Health Assessment for the Omega Chemical Corporation Superfund Site, Whittier, CA. 11/15/99.
  5. Census Information obtained from the Census Web-page: http://venus.census.gov/cdrom/lookup/933707677
  6. Chan, Sherry. Record of Activity - Site Visit and Interviews. 7/17/99 and 7/31/99.
  7. Camp, Dresser & McKee. Draft Phase 1a Pre-Design Field Investigation Report Omega Chemical Superfund Site. October 1999.
  8. Agency for Toxic Substances and Disease Registry. Public Health Assessment Guidance Manual. U.S. Department of Health and Human Services Public Health Service. 1997.
  9. California Department of Health Services, Drinking Water Field Operations Branch. Vulnerability Assessment and Monitoring Frequency Guidelines. Monitoring Period: January 1, 1999 to December 31, 2001, System No. 1910245 - Santa Fe Springs - City.
  10. Phone Correspondence Concerning the Odors Emitting from Merchant Metals between Craig Cooper, Environmental Engineer, with the United States Environmental Protection Agency - Superfund Division and Sherry Chan, Research Specialist, with the California Department of Health Services-Environmental Health Investigation Branch. 12/15/99.
  11. U.S. Environmental Protection Agency, Integrated Risk Information System. http://www.epa.gov/docs/ngispgm3/iris/subst/.
  12. U.S. Environmental Protection Agency, Toxic Chemicals Fact Sheets (Open Data Solutions, Inc.). http://mail.odsnet.com/TRIFacts/.
  13. National Institutes of Health, National Toxicology Program - Chemical Health and Safety Data. http://ntp-server.niehs.gov/Main_Pages/Chem_HS.html.
  14. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Tetrachloroethylene. Atlanta: ATSDR, September 1997.
  15. Agency for Toxic Substances and Disease Registry. Hazardous Substance Fact Sheet for Benzo(a)pyrene. http://www.atsdr.gov
  16. Agency for Toxic Substances and Disease Registry. Hazardous Substance Fact Sheet for Antimony. http://www.atsdr.gov
  17. Agency for Toxic Substances and Disease Registry. Hazardous Substance Fact Sheet for Arsenic. http://www.atsdr.gov
  18. Agency for Toxic Substances and Disease Registry. Hazardous Substance Fact Sheet for Chromium. http://www.atsdr.gov
  19. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Barium. Atlanta: ATSDR, July 1992
  20. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Nickel. Atlanta: ATSDR, September 1997.
  21. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Vanadium. Atlanta: ATSDR, July 1992
  22. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Acetone. Atlanta: ATSDR, May 1994.
  23. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Benzene. Atlanta: ATSDR, September 1997.
  24. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Chloroform. Atlanta: ATSDR, September 1997.
  25. Agency for Toxic Substances and Disease Registry. Toxicological Profile for 1,2-Dichloroethane. Atlanta: ATSDR, August 1999.
  26. Agency for Toxic Substances and Disease Registry. Toxicological Profile for 1,1-Dichloroethene. Atlanta: ATSDR, May 1994.
  27. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Methylene Chloride. Atlanta: ATSDR, April 1993.
  28. Agency for Toxic Substances and Disease Registry. Toxicological Profile for 1,1,1-Trichloroethane. Atlanta: ATSDR, August 1995.
  29. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Trichloroethylene. Atlanta: ATSDR, August 1995.
  30. New Jersey Department of Health and Senior Services. Hazardous Substance Fact Sheet for Trichlorofluoromethane, Revised June 1998.

Next Section     Table of Contents

  
 
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Agency for Toxic Substances and Disease Registry, 4770 Buford Hwy NE, Atlanta, GA 30341
Contact CDC: 800-232-4636 / TTY: 888-232-6348

A-Z Index

  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #