PETTITIONED PUBLIC HEALTH ASSESSMENT
KOPPERS COMPANY, INCORPORATED (OROVILLE PLANT)
[a/k/a KOPPERS (OROVILLE)]
OROVILLE, BUTTE COUNTY, CALIFORNIA
Figure 2. Site Layout and Soil Remediation Areas
Figure 3. Well Locations and PCP Plume Delineation
Figure 4. Approximate Extent of Groundwater Contamination (1988)
Figure 5. Soil Sample Locations
TABLE 1. EXPOSURE PATHWAYS, KOPPERS Co., OROVILLE, CA
|
PATHWAY NAME
|
EXPOSURE PATHWAY ELEMENTS |
TIME | CONTAMINANTS OF CONCERN | ||||
|
SOURCE |
MEDIA |
POINT OF EXPOSURE |
ROUTE OF EXPOSURE |
EXPOSED POPULATION |
|||
|
COMPLETED EXPOSURE PATHWAYS |
|||||||
| OFF-SITE GROUNDWATER | KOPPERS | groundwater | domestic wells to the south | ingestion skin contact | residents with domestic wells
(120 residents) |
past | PCP |
| ON-SITE GROUNDWATER | KOPPERS | groundwater | supply wells | ingestion skin contact inhalation | workers
(50-100 workers) |
past | arsenic benzene, PAHs, PCP dioxins |
| ON-SITE SOIL | KOPPERS | soil | fire areas and treated work storage areas |
ingestion inhalation skin contact | workers trespassers | past present future(2) | arsenic, PCP, PAHs, dioxins |
| FOOD CHAIN | KOPPERS | chicken eggs beef |
off-site farms | ingestion | consumers | past present future | dioxins |
| ON-SITE AIR
|
ON-SITE FIRES AT KOPPERS | air | on-site work areas
|
inhalation | workers
|
past | No contaminants measured on site during the RI exceed comparison values. |
|
POTENTIAL EXPOSURE PATHWAYS |
|||||||
| PERIPHERAL SURFACE WATER | KOPPERS site drainage | surface water | seasonal ponds at periphery of site | skin contact ingestion | children playing in ponds and workers | past present future | dioxins, boron, arsenic, PCP |
| PERIPHERAL STREAM SEDIMENTS | KOPPERS site drainage | sediments | ditches, ponds on site periphery | skin contact | trespassers and workers | past present future | dioxins, arsenic PAHs |
| ON-SITE GROUNDWATER | KOPPERS | groundwater | supply wells | skin contact | workers | present future | arsenic, benzene, PAHs, PCP, dioxins |
|
ELIMINATED EXPOSURE PATHWAYS |
|||||||
| OFF-SITE GROUNDWATER | KOPPERS | groundwater | domestic wells to the south | ingestion skin contact | residents | present future | no contaminants exceed comparison values in domestic wells tested. |
| OFF-SITE SOIL | KOPPERS | soil | resident and farm areas to the south | ingestion skin contact | residents | past present future | no contaminants exceed comparison values. |
TABLE 2. CONTAMINANTS IN GROUNDWATER, KOPPERS Co., OROVILLE,
CA
|
CONTAMINANT
|
MAXIMUM CONCENTRATION (ppb) | COMPARISON VALUE | ||
| GROUNDWATER | CONCENTRATION (ppb) |
REFERENCES | ||
| ON SITE | OFF SITEa | |||
| arsenic | 22 | 27 | 3
10 0.02 |
EMEG (child) EMEG (adult) CREG |
| benzene | 19 | ND | 1 | CREG |
| benzo(a)pyrene equivalents | 819 | 0.009 | 0.005 | CREG |
| pentachlorophenolb | 44,000 | 5,500c | 0.3
300 1000 |
CREG
RMEG (child) RMEG (adult) |
| 2,3,7,8-TCDD equivalents | 0.00028 | 0.0000041 | 0.00003
0.00001 |
MCL
EMEG (child) |
a Includes both off-site monitoring well data and domestic wells.
b Cleanup goal for pentachlorophenol = 2.2 ppb
c Highest historic hit of PCP detected in domestic well samples; detected in Well #59 in 1983. The highest PCP concentration detected off site during the RI was 680 ppb in Well RI -03. See Table 1A for history of PCP contamination in domestic wells.
[Source: Ebasco Services, Inc. 1988 and groundwater database (CDHS 1997b)]
TABLE 3. DOMESTIC WELLS WITH HISTORY OF PCP CONTAMINATION,
KOPPERS Co., OROVILLE, CA
| WELL NO. | CONCENTRATION RANGE (ppb) |
DATE OF MAXIMUM CONCENTRATION |
DATES OF AVAILABLE DATA |
| 31C2 | <0.1-2,100 | 4/2/74 | 1973-1993 |
| 31D3 | <1.0-9.1 | 7/20/73 | 1973-1981 |
| 59 | <0.1-5,500 | 12/16/83 | 1983-1998 |
| 60 | <0.1-210 | 4/13/84 and 3/22/85 | 1984-1989 |
| 61 | <0.1-300 | 6/6/94 | 1983-1998 |
| 62 | <0.1-640 | 1/18/84 | 1984-1986 |
| 81 | <0.1-133 | 6/20/84 | 1984-1990 |
Note: Most post-1985 data ranged from <0.1 to 64 ppb.
[Sources: EPA 1998; Schmidt 1984.]
TABLE 4. CONTAMINANTS IN ON-SITE AIR (1988), KOPPERS Co.,
OROVILLE, CA
|
CONTAMINANT
|
MAXIMUM |
COMPARISON VALUE |
|
|
CONCENTRATION |
REFERENCES |
||
| ON SITE | |||
| Benzo(a)pyrene equivalents | 0.005 | NA | NA |
| pentachlorophenol | 0.42 | 500 | REL |
| arsenic | 0.026 | 2
0.0002 |
REL
CREG |
µg/m3: micrograms per cubic meter
CREG: Cancer Risk Evaluation Guide
REL: Recommended Exposure Limit (occupational)
NA: none available[Source: Dames & Moore 1988a]
TABLE 5. MAXIMUM DIOXIN LEVELS IN FOOD PRODUCTS OFF SITE
| Food Producta | Concentration (ppt ITEQ) |
| Eggs (Index Homes #1 and #2) | 18.26 |
| Eggs (25 S. Oroville homes/average) | 2.0 |
| Eggs (commercial/average) | <1 |
| Chickens (index home) | 177-228 |
| Beef (index home) | 27.2 |
| Cow liver (pre-fire) | 12.1 |
| Cow liver (post-fire) | 10.7 |
| Home-produced milk | 10.3 |
| Commercial milk | 1.1 |
ppt: parts per trillion
ITEQ: International Toxicity Equivalence (as calculated by
CDHS). One concentration reported based on the weighted sum (based on relative
toxicity) of the many dioxins and furans (congeners) detected in the samples.
aEgg concentrations are reported on a whole egg basis. Chicken, beef, liver, and milk data are presented on a total fat basis.
[Source: CDHS 1997c]
TABLE 6: DIOXIN/FURAN CONCENTRATIONS IN HOME-PRODUCED
EGG SAMPLES (1987-1988)
| Congener | Maximum concentration
(ppt)a |
Mean concentration within 11 kilometers
(ppt)b |
ITEF | Maximum ITEQ concentration
(ppt) |
ITEQ concentration within 11 kilometers
(ppt) |
| OCDD | 70.20 | 20.9 | 0.001 | 0.07 | 0.0209 |
| OCDF | 4.20 | 1.26 | 0.001 | 0.0042 | 0.00126 |
| HpCDD | 75.60 | 14.1 | 0.01 | 0.756 | 0.141 |
| HpCDF | 10.0* | 2.18* | 0.01 | 0.10 | 0.0218 |
| HxCDD | 55.7* | 7.67* | 0.1 | 5.57 | 0.767 |
| HxCDF | 9.93* | 1.83* | 0.1 | 0.993 | 0.183 |
| PeCDD | 19.8 | 2.8 | 0.5 | 9.9 | 1.4 |
| 1,2,3,7,8-PeCDF | 2.10 | 0.38 | 0.05 | 0.105 | 0.019 |
| 2,3,4,7,8-PeCDF | 1.40 | 0.51 | 0.5 | 0.7 | 0.255 |
| TCDD | NA | NA | 1 | -- | -- |
| TCDF | 0.63 | 0.35 | 0.1 | 0.063 | 0.035 |
| TOTAL** | 18.26 | 2.8 |
**In 1998 the World Health Organization (WHO) raised the TEF for 1,2,3,7,8-Pentachlorodibenzo-p-dioxin (PeCDD) from 0.5 to 1.0 and decreased the TEFs for OctaCDD and OctaCDF to 0.0001. If these new TEFs were used, the estimate of total TEQs listed in Table 6 would increase from 18.26 to 28.09. However, neither this increase in home-produced eggs, or a similar increase, in soils, sediment, groundwater, and blood would alter ATSDR's health conclusions at this site.
TABLE 7. CONTAMINANTS IN SOILS & SEDIMENTS, KOPPERS Co.,
OROVILLE, CA
|
CONTAMINANT
|
MAXIMUM CONCENTRATION (ppm) | COMPARISON VALUE | |||
|
SOILS |
(periphery) |
CONCENTRATION (ppm) |
REFERENCE | ||
| ON SITE | OFF SITE | ||||
| 2,3,7,8-TCDD equivalents | 0.118 | 0.000046a | .003 | 0.00005 0.0007 |
EMEG (child) EMEG (adult) |
| benzo(a)pyrene equivalents |
600 | NA | 3.6 | 0.1 | CREG |
| arsenic | 681 | NA | 17 | 20 200 0.5 |
EMEG (child) EMEG (adult) CREG |
| pentachlorophenol | 33,000 | 0.9a | 4 | 200 20,000 6 |
RMEG (child) RMEG (adult) CREG |
ppm: parts per million
EMEG: Environmental Media Evaluation Guide
RMEG: Reference Dose Media Evaluation Guide
CREG: Cancer Risk Evaluation Guide
NA: not analyzed for
a Data collected by CDHS following 1987 fire (CDHS
1987).
[Source: Dames & Moore 1988.]
TABLE 8. CONTAMINANTS IN PERIPHERY SURFACE
WATER, KOPPERS Co., OROVILLE, CA
CONTAMINANT |
COMPARISON VALUE | ||
| STREAMS (ppm) |
CONCENTRATION
(ppm) |
REFERENCES | |
| arsenic | 0.03 | 0.003 | EMEG |
| benzo(a)pyrene equivalents | 0.0002 | 0.000005 | CREG |
| boron | 1.1 | 0.1 | EMEG |
| pentachlorophenol | 0.14 | 0.0003 | CREG |
| 2,3,7,8-TCDD equivalents | 0.00000028 | 0.00000001 | EMEG |
ppm: parts per million
EMEG: Environmental Media Evaluation Guide
CREG: Cancer Risk Evaluation Guide
[Source: Dames & Moore 1988]
APPENDIX C: ATSDR PUBLIC HEALTH ASSESSMENT METHODOLOGY
Quality Assurance
In preparing this report, ATSDR relied on the information provided in the referenced documents. ATSDR assumes that adequate quality assurance and control measures were taken during chain-of-custody, laboratory procedures, and data reporting. The validity of the analyses and conclusions drawn in this document are determined by the availability and reliability of the information.
The soil, groundwater, surface water, sediment, and well installation reports received from Beazer's contractor (Dames and Moore), including the Remedial Investigation Report (RI/FS), were validated by EPA to assure that samples were analyzed in accordance with quality control requirements stipulated by EPA for Superfund sites. For air particulate samples, EPA-revised data were summarized for the public health assessment. ATSDR used toxic equivalent factors for dioxins and PAHs calculated by CDHS and EPA. No significant quality assurance/quality control problems were noted in file data.
The quality of some of the early groundwater data (pre-RI) has been questioned by EPA and contractors. Specifically, some false positives may have been reported (i.e., actual PCP concentrations in groundwater may have been lower than those reported by the laboratory) (EPA 1997b; Ebasco 1988).
Human Exposure Pathway Evaluation and the use of ATSDR Comparison Values
ATSDR assesses a site by evaluating the level of exposure in potential or completed exposure pathways. An exposure pathway is the way chemicals may enter a person's body to cause a health effect. It includes all the steps between the release of a chemical and the population exposed: (1) a chemical release source, (2) chemical movement, (3) a place where people can come into contact with the chemical, (4) a route of human exposure, and (5) a population that could be exposed. In this assessment, ATSDR evaluates chemicals in the soil and groundwater that people living in nearby residences may consume or come into contact with.
Data evaluators use comparison values (CVs), which are screening tools used only to evaluate environmental data that are relevant to the exposure pathways. Comparison values are concentrations of contaminants that are considered to be safe levels of exposure. Comparison values used in this document include ATSDR's environmental media evaluation guide (EMEG) and cancer risk evaluation guide (CREG). Comparison values are derived from available health guidelines, such as ATSDR's minimal risk levels and EPA's cancer slope factor.
The derivation of a comparison value uses conservative exposure assumptions, resulting in values that are much lower than exposure concentrations observed to cause adverse health effects, thus insuring the comparison values are protective of public health in essentially all exposure situations. That is, if the concentrations in the exposure medium are less than the CV, the exposures are not of health concern and no further analysis of the pathway is required. However, while concentrations below the comparison value are not expected to lead to any observable health effect, it should not be inferred that a concentration greater than the comparison value will necessarily lead to adverse effects. Depending on site-specific environmental exposure factors (for example, duration of exposure) and activities of people that result in exposure (time spent in area of contamination), exposure to levels above the comparison value may or may not lead to a health effect. Therefore, ATSDR's comparison values cannot be used to predict the occurrence of adverse health effects.
The comparison values used in this evaluation are defined as follows:
Cancer Risk Evaluation Guides (CREGs) are concentrations of a contaminant in air, water, of soil which, assuming default values for (adult) body weight and intake rates, would correspond to exposure doses estimated to produce no more than one excess cancer in a million persons exposed. CREGs are calculated from EPA's cancer slope factors and therefore reflect estimates of "risk" based on the assumption of zero threshold and lifetime exposure. It should be noted, however, that the true risk is unknown and could be as low as zero.
The CREG is used to evaluate potential cancer effects. The CREG is the most conservative of comparison values because it assumes that no threshold exists for the effects of chemical carcinogens. The resulting CREG can therefore often be below typical background levels and common detection limits. CREGs do not define levels of actual hazard (e.g., a 1-in-a-million "risk" level) and cannot be used to predict actual cancer incidence under specified conditions of exposure. As stated in EPA's 1986 Cancer Risk Assessment Guidelines, "the true risk is unknown and may be as low as zero."
Environmental Media Evaluation Guides (EMEGs) are concentrations of a contaminant in air, water, or soil that are calculated from ATSDR's Minimal Risk Levels (MRLs) for acute, intermediate, or chronic exposure by factoring in default body weights and ingestion rates for adults and children (and, in the case of soil, pica children). The Minimal Risk Levels (MRLs) on which the EMEGs are based are ATSDR's estimates of daily human exposure doses of a contaminant (expressed in mg/kg/day) that the agency considers unlikely to be associated with any appreciable risk of deleterious noncancer effects over a specified duration of exposure. MRLs are calculated using data from human and animal studies and, like the EMEGs derived from them, are reported for acute (< 14 days), intermediate (15-364 days), and chronic (> 365 days) exposures. MRLs are published in ATSDR Toxicological Profiles for specific chemicals, but the EMEGs are not.
Reference Dose Media Evaluation Guides (RMEGs) are concentrations of a contaminant in air, water or soil that are calculated from EPA's Reference Doses (RfDs) for chronic exposure by factoring in default values for body weights and intake rates in children and adults. The EPA Reference Doses (RfDs) from which the child and adult RMEGs are calculated are estimates of the daily human exposure dose of a contaminant (expressed in mg/kg/day) that EPA considers unlikely to be associated with any appreciable risk of deleterious noncancer effects over a lifetime of exposure. Thus, ATSDR's MRLs and EMEGs are analogous to RMEGs and RfDs.
Maximum Contaminant Levels (MCLs) are legally-enforceable drinking water standards promulgated by the EPA. They represent contaminant concentrations in drinking water that EPA deems protective of public health (considering the availability and economics of water treatment technology) over a lifetime (70 years) at an exposure rate of 2 liters of water per day.
Recommended Exposure Limits (RELs) are time-weighted average (TWA) concentrations considered safe for up to a 10-hour work day during a 40-hour work week. RELs are set by the National Institute for Occupational Safety and Health (NIOSH).
Selecting Contaminants of Concern
Contaminants of concern (COCs) are the site-specific chemical substances that the health assessor selects for further evaluation of potential health effects. Identifying contaminants of concern is a process that requires the assessor to examine contaminant concentrations at the site, the quality of environmental sampling data, and the potential for human exposure. A thorough review of each of these issues is required to accurately select COCs in the site-specific human exposure pathway. The following text describes the selection process.
In the first step of the COC selection process, the maximum contaminant concentrations are compared directly to health comparison values. ATSDR considers site-specific exposure factors to ensure selection of appropriate health comparison values. If the maximum concentration reported for a chemical was less than the health comparison value, ATSDR concluded that exposure to that chemical was not of public health concern; therefore, no further data review was required for that chemical. However, if the maximum concentration was greater than the health comparison value, the chemical was selected for additional data review. In addition, any chemicals detected that did not have relevant health comparison values were also selected for additional data review.
Comparison values have not been developed for some contaminants, and, based on new scientific information, other comparison values may be determined to be inappropriate for the specific type of exposure. In those cases, the contaminants are included as contaminants of concern if current scientific information indicates exposure to those contaminants may be of public health concern.
The next step of the process requires a more in-depth review of data for each of the contaminants selected. Factors used in the selection of the COCs included the number of samples with detections above the minimum detection limit, the number of samples with detections above an acute or chronic health comparison value, and the potential for exposure at the monitoring location.
APPENDIX D: SUMMARY OF BIOLOGIC MONITORING AND HEALTH OUTCOME DATA
The California Department of Health Services (CDHS) has collected health information data from individuals residing in the vicinity of the Koppers Company, Inc. (Koppers) site. The findings and implications of the following three studies are summarized below:
Biologic Monitoring and Health Interview Study among Residents of an Area with Pentachlorophenol Contaminated Water
In 1985 and early 1986, CDHS conducted a health study targeting residents who may have consumed water from domestic wells contaminated with PCP (32 households south of the Koppers facility). CDHS selected "exposure" households (near Koppers) and "control" households (in Honcut, CA) and then administered health questionnaires, monitored tap water, and collected urine samples from potentially exposed and control groups. Study participants were asked about their residential histories, health histories, water usage habits, hazardous substance exposure histories, lifestyles, and observations about their water supply. CDHS issued a report presenting the findings of this study in June 1997 (CDHS 1997a).
The CDHS health study documented symptoms reported by individuals living in households south of Koppers (the "exposure" group) and individuals never thought to have been exposed to PCP in their groundwater (the "control" group). CDHS also evaluated PCP levels in tap water and urine from individuals within each group.
Although both groups reported similar perceptions of overall health (65% to 70% in both groups reported good or excellent health), 57% of the exposed group reported worsened health conditions since moving to their present address, as compared with 25% of the control group. Specific symptoms reported by the exposed group include frequent or severe headache (45%), skin irritation (45%), and fatigue (42%). In addition, people in the exposed group were more likely to report skin irritation or rashes after bathing (53%), compared with the control group (14%) (CDHS 1997a).
CDHS collected tap water samples between December 1985 and February 1986 and reviewed historic PCP data collected between January 1984 to April 1986. The highest PCP concentration measured by CDHS in tap water was 0.16 ppb, and the average PCP concentrations in exposure area households were at levels typically found in US drinking water and not different from levels in water from control households.
Likewise, average urine PCP levels, reported as milligrams per gram (mg/g) creatinine, were the same in the exposed and control groups (0.0029 mg/g and 0.0036 mg/g creatinine, respectively), consistent with levels found in the general US population (CDHS 1997a). PCP in urine is a useful "biomarker" of exposure. That is, if exposure is occurring, PCP would be detected in urine proportional to the extent of exposure. In general, no simple relationship between health effects and levels of PCP detected in the urine exists. The American Conference on Governmental and Industrial Hygienists (ACGIH) has developed what it calls a biologic exposure index (BEI) guideline for PCP of 2 mg/g creatinine (ACGIH 1996). The BEI is a guideline used to evaluate the likelihood that a worker might experience an adverse health effect. Although developed for use in the workplace, the PCP BEI can be used as a guide here to evaluate the significance of measured PCP levels. As can be seen, measured levels are much lower than the BEI.
CDHS also reported that the average PCP concentration measured in domestic wells located in the exposure study area between January 1984 and March 1986 was 11.4 ppb, with a maximum concentration of 640 ppb (in January 1984). PCP was detected in earlier samples (1983) at concentrations up to 5,500 ppb. Many of the exposed group reported odors in their water in the past. CDHS considered water odor as a possible indicator of exposure to PCP. CDHS performed various statistical analyses to evaluate a possible link between self-reported symptoms and presumed historic exposure to PCP-contaminated water. CDHS concluded that living in the "exposure" area, and independently reporting water odor, were strongly associated with self-reported symptoms (CDHS 1997a).
Because exposure data (groundwater and urine data) were collected following times of possible exposures, however, no definitive link can be made between exposure to PCP in drinking water and reported symptoms. As concluded by CDHS, PCP exposure is simply one of several possible explanations of the elevated reporting of symptoms (CDHS 1997a).
Koppers Fire Report
Between April 11 and 13, 1987 CDHS conducted a health investigation of residents and workers affected by the April 6, 1987, fire at Koppers. With the cooperation of the Butte County Department of Public Health and the California Occupational Safely and Health Administration (Cal/OSHA), CDHS rapidly responded to community health concerns by setting up a medical clinic to screen area residents and workers. The investigation included telephone surveys, written questionnaires and interviews, medical exams, and blood and urine PCP measurements and was initiated in response to the large number of phone complaints received by the county health department immediately following the fire at Koppers. Nearly 500 persons participated in the screening; approximately 100 residents participated in telephone interviews. In addition, CDHS helped organize medical, blood, and urine screening for Koppers' workers following the fire. CDHS recorded blood and urine PCP levels and symptoms experienced by individuals exposed to smoke during the fire (CDHS 1987). The results and implications of the findings are summarized below.
Residents
Telephone Screening: One hundred and eight residents participated in the telephone survey, but did not attend the screening clinic. The most common symptoms reported in the first two days after the fire were headache (40.5%), nausea (28.6%), and skin rash (19%). Other symptoms reported included skin irritation, diarrhea, dizziness, and intense thirst. All these symptoms could be associated with acute PCP exposure or with exposure to smoke in general.
Clinic Screening Results: CDHS conducted medical exams of 268 persons who were considered at highest risk for exposure. Several of those examined complained of exposure related symptoms, including sore throat (23%), fatigue (22%), sore nose (8%), and chest pain and tightness (2%). Medical examinations revealed several individuals with skin irritations that included unusual nose, mouth and skin blisters, and rashes. Others who reported watching the fire had abnormal swelling of the eyelids, conjunctivae, and nasal mucous membranes. A total of 26% had unusual skin reactions.
Blood Testing: Serum levels of PCP in the 224 individuals tested were below 0.355 milligrams per liter (mg/L), consistent with those typically found in the general public and lower than those reported for exposed workers at Koppers. Levels below 1.3 mg/L are not expected to be associated with adverse health effects (ATSDR 1994).
Urine Testing: Only 36 of 448 urine samples had measurable levels of PCP, with the highest PCP level reported at 0.156 mg/g creatinine. The average level was 0.02 mg/g creatinine (CDHS 1987). These levels fall well below the BEI of 2 mg/g creatinine.
Some limitations exist in using blood and urine PCP data collected several days after the fire as a measure of acute PCP exposure. How quickly PCP is eliminated from the body following acute inhalation exposures is uncertain. Studies report "half-life" values ranging from 10-30 hours to 20 days (Casarett 1969; Braun et al. 1979; Uhl et al. 1986). Without actual data, knowing what blood and urine levels were immediately following exposures is impossible. Nonetheless, as is concluded in the CDHS report, the blood and urine PCP levels measured 5-7 days following the fire were not indicative of high enough PCP exposures to result in systemic toxicity.
In summary, the information gathered by CDHS indicates that resident exposures to smoke during the fire appear to have resulted in a variety of adverse health effects. These effects cannot be linked with a specific causative agent, however, because of the low levels of PCP measured in urine/serum and the lack of air data at the time of the fire.
Workers
During the April 6, 1987, fire at Koppers, three employees were on site. After the fire, work at Koppers continued as usual, with some staff performing maintenance on equipment in the area of the fire. Access was restricted on April 9, however, to the areas affected by the fire and the surrounding 50 feet. On April 10, California Occupational Safety and Health Administration (CalOSHA) restricted access to the entire Koppers facility except for essential safety and investigation activities.
Seventy-three workers were screened at the community screening clinic, including 20 firefighters, 16 L-P workers, 12 Sierra Pacific workers, and eight members of the press who covered the fire. Thirty-one of the workers screened were involved in emergency response activities. In general, the percentage of these workers reporting symptoms was low compared with the community group, likely because preventive measures were taken to limit exposures (CDHS 1987).
In addition to the community screening, CalOSHA coordinated medical screening of all Koppers employees, including a questionnaire, serum and urine sampling, and a physical exam. Participation was optional. A total of 57 Koppers workers participated in the medical screening. Workers reported symptoms similar to those of residents, including sore throat (26%), headache (26%), cough (18%), nausea (7%), intense thirst (7%), and eye irritation (7%) in the week following the fire. Only 4% reported skin irritation (CDHS 1987).
Blood Testing: Seventy-two serum PCP levels were reported. The levels ranged between 0.018 and 6.895 mg/L, with 90% tested below 1.9 mg/L and an average of about 0.60 mg/L. As mentioned previously, studies have shown that effects are not typically seen when serum PCP levels are less than 1.3 mg/L. One study found that workers exposed to PCP who had average serum PCP levels of 5.14 mg/L had an increased risk for adverse renal (kidney) effects. In general, kidney effects observed in workers exposed to PCP were mild and reversible once exposure ended (ATSDR 1994). Another study, looking at worker exposures and examining nervous system effects associated with PCP exposure, showed no effects in workers with serum PCP levels ranging between 0.038 and 1.27 mg/L (Triebig et al. 1987).
Urine Testing:PCP levels in sampled urine ranged from 0.005 mg/g creatinine to 1.171 mg/g creatinine, with an average of 0.14 mg/g creatinine. No workers had levels exceeding the worker exposure guideline (i.e., the previously described BEI) of 2 mg/g creatinine.
Most workers with measurable urine PCP levels also held jobs that were most likely to bring them into direct contact with PCP, so the levels do not necessarily reflect PCP exposure resulting from the on-site fire. Urine PCP creatinine levels are a relatively good measure for chronic exposures because the half-life of PCP in urine can be up to 20 days (Kalman and Horstman 1983, as cited in CDHS 1987).
Eleven employees were voluntarily rechecked 20 days later for urine PCP levels. None had worked in areas where they might have been exposed to PCP since the previous medical screening. On average, the levels were about half what they were initially. This second screening seems to substantiate the reported 20-day half life of PCP. This also demonstrates the body's ability to effectively remove contaminants.
In summary, workers may have been affected by the fire on site, although there were fewer reports of adverse health effects than in residents. Serum and urine PCP levels indicate that some workers were likely chronically exposed to PCP, because their levels were higher than those of local residents.
Dioxin Study (Blood Testing )
In 1988, CDHS collected blood samples from nine individuals (from the two "Index Homes," #1 and #2) who consumed eggs and meat that had detected levels of dioxin. A control group of nine persons also had their blood tested for dioxin. The control group consumed locally produced eggs and meat but resided in a rural area with no known dioxin sources. Results indicated that residents from Index Homes #1 and #2 who reportedly ate dioxin-contaminated eggs and meat had serum levels of tetra, penta, and hexa dioxin levels that were elevated (two- to six-fold increases) compared with rural controls (Goldman et al. 1989 and 2000). Although the results demonstrate greater exposure to dioxins in the study group, measured serum levels are lower than those shown in available studies to be associated with adverse health effects.
The serum levels measured per gram of fat averaged 29 ppt ITEQ dioxins in females and 39 ppt ITEQ dioxins in males living in the index homes. Investigators reported an observed dose-response relationship based on the type of diet or length of time of exposure (i.e., people who ate more eggs and/or beef and have done so over longer periods of time had higher blood levels of dioxin). Serum dioxin levels averaged 26.7 ppt I-TEQ in individuals consuming eggs and 63.7 ppt ITEQ in individuals consuming beef. The older members of the study group had the highest average levels of dioxins (65 ppt ITEQ) (Goldman et al. 2000). To the best of ATSDR's knowledge, no adverse health effects have been reported to date in the study group.
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