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In May 1986 the U.S. Environmental Protection Agency nominated the T.H. Agriculture and Nutrition Company, Inc., (THAN) in eastern Fresno County, California, to the National Priorities List (NPL) because of contamination resulting from a pesticide formulation facility that was owned and operated by a succession of companies including Ciba-Geigy, Olin, De-Pester Western, and THAN from approximately 1951 until 1981. The site consists of the five-acre formulation facility which is surrounded by approximately 20 acres of almond orchard and vineyard that are owned by THAN. The site is located in an agricultural and low density residential area east of the City of Fresno boundary. The California Department of Toxic Substances remained the lead agency for site investigation activities with oversight from the Regional Water Quality Control Board and the U.S. Environmental Protection Agency.

Pesticide and volatile organic chemical contamination have been detected in the on-site subsurface soil, on-site groundwater, and off-site groundwater. While the site was in operation, the nearby residents complained many times to the air pollution control district of putrid emissions emanating from the THAN site. The nearby residents were also concerned about the levels of dust coming from the site and the general handling practices of THAN. Residents reported that while the plant was in operation, they suffered from a series of health complaints, some of which appeared to be acute in nature and others that have continued since 1981. Respiratory problems, skin irritations and rashes, and headaches were the predominant symptoms that were enumerated by the residents. Residents also reported health concerns related to their pets and farm animals.

Based on the information reviewed, The California Department of Health Services (CDHS) and the Agency for Toxic Substances and Disease Registry (ATSDR) conclude that when the THAN facility was in operation it posed a public health hazard to nearby residents that inhaled air emissions from the site. From 1969 to 1981, the local air pollution control district received numerous odor and health complaints from nearby residents. These complaints were most likely due to the processing of two sulfur-containing compounds with low odor thresholds, mercaptan impurities present in the formulations. It is difficult to assess the level of health impact from this exposure pathway because insufficient air monitoring data is available. Several studies have documented similar odor-related complaints and acute health symptoms in communities located near agricultural fields where sulfur-containing cholinesterase-inhibitor pesticides have been applied. It is not known whether these compounds may be associated with long-term health effects because there is very little toxicological information about these compounds. Given the work practices that resulted in the odiferous chemicals migrating off-site, the possibility exists that other chemicals with higher odor thresholds also migrated off-site.

When the facility was in operation, the site was a public health hazard to on-site workers not wearing adequate respiratory protection. The California Occupational Safety and Health Administration (Cal OSHA) documented work conditions that exceeded the allowable air concentrations for worker exposure to diphenamid, trifluralin, and nuisance dust during DeFend formulation. Although the employees were wearing respirators, on one of the visits, THAN was cited for supplying the wrong respirator filters and for the employees incorrectly wearing the respirators. Exposure to trifluralin and diphenamid may have resulted in non-cancer health effects and trifluralin exposure may have resulted in a minimal increased cancer risk to the employee. The inadequate worker safety practice suggests that it is possible that the process workers were exposed to any number or all of the chemicals that were handled at the facility.

Additionally, when the facility was in operation, the site may have posed a public health hazard to THAN workers who were exposed through dermal contact and incidental ingestion to the contamination in the on-site surface soil. In three surface soil samples taken on site, the only contaminants detected were DDT and DDE. However, the subsurface soil is contaminated with many chemicals at levels above health comparison values. Workers exposed to DDT and DDE in soil at the site may experience noncancer health effect, and those who may have been exposed for 13 years may have a moderate increased cancer risk.

The site did pose and perhaps still poses a public health hazard to those people (residents, off-site workers, Temperance Kutner school children) that used or use a contaminated well for domestic purposes. Most of the private wells downgradient of the site are contaminated with DBCP and nitrates. Chloroform (18 private wells), 1,2-dichloroethane (21 private wells), dieldrin (10 wells), lindane (1 well), -HCH (13 wells) has been detected in certain downgradient private wells at levels of health concern. DBCP, chloroform, and nitrates have been detected at levels of health concern in the Temperance-Kutner school.

Since 1988 when THAN first provided for bottled water and then for the extension of the municipal water system to 64 homes and the elementary school located southwest of the site, exposures through use of contaminated groundwater should not have occurred for those residents and schoolchildren.

There is inadequate toxicological information, especially about noncancer health effects, to evaluate the health impact of the low-level, long-term exposures that may have occurred. Additionally, little is known about exposure to multiple compounds. However, those residents whose wells were contaminated with chemicals other than DBCP may have, based on what is known, a slight to minimal increased lifetime cancer risk because of past exposure to chloroform, 1,2-dichloroethane, dieldrin, and -HCH. Residents who used water from wells contaminated with DBCP, but not other chemicals may have a low increased cancer risk. A health study would not be able to detect this increased cancer risk because of the small number of people that were exposed.

Nearby residents who drank or showered with the contaminated groundwater posed a number of health concerns. Significant scientific gaps limit a complete understanding of the human health impact to residents living near the site. Many reported health effects (headaches, nausea, vomiting, diarrhea, skin inflammation, heart/blood system effects, and liver changes) are associated with some of the chemicals present in groundwater, but the effects usually are associated with much higher levels than those found in the groundwater used by the people. Reproductive changes have been associated with DBCP exposure. Immunological and neurological changes are not easily evaluated because of little toxicological information on how the groundwater contaminants may affect those processes upon exposure. A number of compounds in the groundwater are thought, based on animal studies, to be carcinogenic; thus, a slight increased cancer risk may exist for people exposed to those compounds.

In addition to the site's contribution to the groundwater contamination, an area-wide DBCP and nitrate problem exists because of previous agricultural practices in eastern Fresno County. DBCP, as a probable human carcinogen, poses an increased cancer risk to those people with on- going exposure. The nitrate in the groundwater may cause methemoglobinemia (change in blood that results in abnormal coloration of the skin and mucous membranes and other serious effects) in infants who drink the contaminated water.

Cancer incidence (1988-1991) in the two census tracts surrounding the site does not appear to be unusual and is very similar to that seen for Fresno County as a whole. The birth defect rate (1986-1991) in the zip code area surrounding the site is comparable to the rate for the rest of Fresno County and the rest of the state. Several epidemiological surveys that evaluated cancer and reproductive outcomes as a result of exposure to the area-wide, DBCP-contaminated groundwater have been inconclusive.

Community concern is very high, and the people are frustrated that no one has acted on their concerns. CDHS is discussing actions that may be taken with ATSDR. CDHS has included inquiries into site-specific education, further health statistics review, and the possibility of an exposure registry.

Additionally, CDHS and ATSDR have identified the following recommendations for implementing actions to protect public health: ensure that the contaminated soil will not migrate off-site through fugitive dust generation; institute groundwater remediation to reduce the spread of the contamination; reduce the potential migration of contaminants into the groundwater from the soil; conduct a well study in the eastern Fresno County area to identify all private wells and their uses; maintain monitoring of the private wells in the area that may be potentially affected; provide an alternative water source if wells become contaminated with site-associated chemicals; when activities occur on-site that involve disturbing contaminated soil, appropriate protective clothing and respiratory protection should be worn by workers; implement deed and building restrictions to prevent future development on the site until contamination has been reduced to levels below health concern; sample the water from the private wells in the eastern part of Fresno County that have not recently been tested by an accredited laboratory. Analyze the well water for DBCP and nitrate, at a minimum; conduct air monitoring during any site-activities that involve disturbing contaminated soil; inform the area residents of the chemicals (background and site-associated) typically found in the groundwater and the health implications of exposure to those contaminants; provide professional health education for local physicians about health effects of site-related contaminants including DBCP.

The data and information developed in this public health assessment have been evaluated for appropriate follow-up health actions. The ATSDR Health Activities Recommendation Panel (HARP) determined that people have been exposed to contaminants from the site at levels that may cause illness and disease. HARP determined that further health statistics review is indicated. Site-specific community and health providers education is indicated. ATSDR will reevaluate this site for additional follow-up public health actions if new data become available that indicate a need to do so.

The public health action plan (PHAP) for this site contains a description of actions to be taken by ATSDR and/or other governmental agencies at and in the vicinity of the site subsequent to the completion of this public health assessment. The purpose of the PHAP is to ensure that this public health assessment not only identifies public health hazards, but provides a plan of action designed to mitigate and prevent adverse human health effects resulting from exposure to hazardous substances in the environment. Included is a commitment on the part of CDHS and ATSDR to follow up on this plan to ensure that it is implemented.

In coordination with other involved agencies and the THAN community advisory committee, CDHS has, and will continue to provide community health education and to inform the community about possible health effects from site-related contaminants.

In addition to the on-going community involvement and education activities, CDHS have worked with the community to develop and provide appropriate and useful health professional education for local health care providers.

CDHS will further evaluate the cancer registry data using a Geographical Information System (GIS). That will allow evaluation of the geographic distribution of the cancer data within the census tracts. (Although cancer statistics evaluation is provided in this document, the data include people who were not actually exposed to contaminants at the site. GIS will allow better designation of the geographical areas and people actually exposed.) When the health statistics review is available, CDHS will report the results through a health consultation that will be shared with the community.

The state, with the high level of community concern in mind, inquired about the establishment of a registry or a similar procedure for long-term follow-up of people accidently exposed to pesticides at hazardous waste sites. That inquiry was reviewed by ATSDR's Division of Health Studies. The subregistries of the ATSDR National Exposure Registry are composed of persons with documented exposure to certain chemicals. At this time subregistries have been created for persons with documented exposure to trichloroethylene, benzene, dioxin, and chromium. A subregistry for any of the pesticides has not been established at this time, but all chemicals are continuously reviewed for inclusion. However, pesticides represent a broad group of chemicals, and a subregistry for non-specific pesticide exposures would not provide the chemical-specific information on health effects that registries are designed to provide.


The California Department of Health Services (CDHS) has prepared this public health assessment under cooperative agreement with the U.S. Agency for Toxic Substances and Disease Registry (ATSDR). CDHS and ATSDR will determine whether health effects are possible because of exposure to site contaminants and will recommend actions to reduce or prevent possible adverse health effects. ATSDR, located in Atlanta, Georgia, is a federal agency within the U.S. Department of Health and Human Services and is authorized by the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) to conduct health assessments at hazardous waste sites. The conclusions of this public health assessment for the T.H. Agriculture and Nutrition (THAN) site is based on a review of available environmental, occupational, health data, and community concerns, and information obtained from site visits and consultation with involved agencies and the public.

The U.S. Environmental Protection Agency (U.S. EPA) added the THAN site to the National Priorities List (NPL) in May 1986. The NPL informs the public about hazardous waste sites that warrant further investigation to determine if they pose risks to public health or the environment. Clean-up activities for sites included on the NPL can be paid for through funds established by CERCLA.


The THAN site consists of five acres of the approximately 25 acres owned by Thompson Hayward Agriculture and Nutrition Company, Inc. (THAN), located at 7183 East McKinley Avenue in Fresno County, about three miles east of Fresno, California (Figure 1). The remainder of the THAN property is an orchard and vineyard surrounding the site on its south, east, and west boundaries (Figure 2). Properties surrounding THAN's 25 acres consist of farms, orchards, vineyards, and low density residential developments.

The site is the former location of an agricultural chemical formulation, packaging, and warehousing plant, which was in operation between 1951 and 1981 by a succession of owners (1). From 1959 until present, the site has been owned and operated by THAN. A list of chemicals known to have been handled by the succession of owners and operators at the site is presented in Table 1 (1).

Historically, the plant has consisted of a main plant building connected to a warehouse, various outbuildings, and storage areas (Figure 3). The most prominent structure was the large two-story brick building that was used primarily for agricultural chemical storage, packaging, and formulation during the plant's operation (1). The loading dock area north of the brick building was used to transfer chemicals between railroad cars and the brick building. The adjacent timber warehouse was used primarily for storing raw and packaged materials. A quality control laboratory was located at the western side of the building. A large metal warehouse located on the south portion of the site was used for storage of packaged products.

Hazardous wastes and hazardous substances were disposed on-site by the owners and operators during the years of plant operation (2). On-site disposal and waste handling procedures included: landfilling of empty pesticide containers, waste containing pesticide residues, and other hazardous substances; incineration of trash; storage of liquid hazardous wastes in a concrete sump and tank prior to off-site disposal; disposal of wastewater and lab wastes to several on-site cisterns; and disposal of cooling water to on-site dry wells.

In addition to these disposal practices, between 1951 and 1983, the owners and operators of the plant contributed to contamination of the site and groundwater by storing hazardous substances in areas not provided with adequate containment; not containing surface water drainage which allowed vertical migration of contaminants; and employing inadequate loading procedures which allowed hazardous materials to spill and contaminate the plant's railroad loading dock areas (2).

When the site was in operation the Fresno County Air Pollution Control District of the Fresno County Health Department (now part of the San Joaquin Valley Unified Air Pollution Control District) received many odor complaints from residents living around the THAN site (3). The number of odor complaints ranged from 0 to 7 per year between 1969 to 1980 and 23 complaints in 1981. The staff from the air pollution control district would typically respond to the complaints by visiting the THAN facility and talking with the THAN staff. Sometimes the complaints seemed to coincide with the mixing of specific pesticide formulations such as DEF, DEFEND, and dimethoate, sulfur-containing compounds with particularly low odor thresholds (4). Fresno County Air Pollution Control District noted smelling distinct odors on several of their visits (5-7).

After the complaints in 1969, THAN voluntarily agreed to store certain chemicals indoors; fill the open disposal pit; ship the steel containers and liners off-site for disposal; use chlorine spray in all vents in order to eliminate odors; and introduce chlorine gas into the dust collectors to eliminate odors (8). However, the complaints continued to be received by the air pollution control district. Over the years THAN took further steps to reduce the emissions from the plant including moving certain operations that were performed outdoors in the ambient air to enclosed, ventilated space; installing charcoal filters in the ventilation system; and adding dampers on the air vents. Finally in 1981, the Fresno County Air Pollution Control District ordered THAN to discontinue the handling, storing, formulating, mixing or packaging of DEF 6-S, DEFEND/W/25 and dimethoate (3).

In response to THAN's request for approval of their waste practices, staff from the Fresno County Health Department and the California Regional Water Quality Control Board (RWQCB) accompanied the plant manager on an inspection of the site January 6, 1976 (9). At that time THAN appeared to be handling the solid waste in an appropriate manner. However, there were concerns about the liquid waste containing hazardous waste. At the time of the inspection, staff from Fresno County and RWQCB observed the wastewater holding tank overflowing onto the ground. Although those wastes were supposedly neutralized (removing the acidity or alkalinity), there was concern that the tank may overflow before treatment of the hazardous material. Additionally, the neutralized waste was being discharged to a City of Fresno septic dump station that was constructed for the purpose of receiving domestic waste.

At the Fresno County's request, THAN performed an analysis of the neutralized wastewater and found dimethoate (119 ppm), DEF-6 (109 ppm), and an unidentified compound (100 ppm) (10). Based on these findings, Fresno County told THAN to store all wastes in an enclosed holding tank; to discontinue disposing of wastewater to any municipal sewer system; and to dispose of the wastewater at an approved Class I disposal site (11).

THAN neighbors were also complaining to the county health department that their well water was being contaminated and causing them adverse health effects. In the spring of 1981, the CDHS Sanitary Engineering Section analyzed samples from domestic wells in the vicinity of THAN (12). The samples contained low levels of certain agricultural chemicals. In order to determine whether these groundwater conditions had any relationship to the THAN site, the RWQCB requested that THAN investigate groundwater conditions at the site (1).

THAN discontinued operations at the site in 1981 (1). THAN removed formulation equipment and agricultural chemical inventory in the summer of 1982, and the plant was closed completely in 1983.

Beginning in 1981, THAN retained the services of an engineering firm to characterize the soil and groundwater conditions at the site. After receiving reports on their findings, RWQCB issued a Cleanup and Abatement Order in February 1984 (1).

In May 1984, the Department of Toxic Substances Control (DTSC) (prior to 1992, a program within CDHS) advised THAN it would be the lead agency overseeing site investigation and cleanup (1).

U.S. EPA added the THAN site to the National Priorities List (NPL) in May 1986 (1). DTSC remained the lead agency with oversight from RWQCB and U.S. EPA.

Since 1981, THAN has conducted several investigations to characterize on-site and near-site subsurface soil contamination and on-site and off-site groundwater contamination, including sampling nearby private wells (1). THAN has also performed various removal activities at the site (13). During these removal activities, THAN's contractors conducted air monitoring in order to protect the health of the workers and nearby residents. In 1984, THAN directed the removal of approximately 14,000 cubic yards of contaminated soil and debris from the former landfill area where trenches and pits had been dug and historically used for disposal of wastes (Figure 3). The laboratory cisterns (former Drainage System A) and surrounding contaminated soils were excavated. At the same time, THAN directed the dismantling of the sump, tanks, and concrete pad in the solvent storage area, the metal-frame shed, and the Dinoseb and Guthion tanks. The excavated soil and debris and the structural demolition material was disposed off-site at a Class I landfill.

In 1988, THAN directed the installation of a soil vapor extraction (SVE) system in the former laboratory area (13) The SVE system was installed in order to study its feasibility to remove chloroform and any other volatile or semi-volatile compounds present in the subsurface soils. THAN estimates that 9,000 pounds of non-methane hydrocarbons have been removed by this SVE system since it began operation.

Between January and April 1989, THAN directed the demolition of five structures at the site, including the two-story brick building and the one-story wood frame building which housed the laboratory (Figure 3) (13). The structures were demolished based on the concentrations of DDT and other chemicals found in samples of their building materials. Approximately 5,100 tons of contaminated building debris was removed from the site. In conjunction with the demolition, THAN directed the excavation of approximately 10,000 cubic yards of contaminated soil from the former solvent storage area, the former railroad loading area, several known drainage systems, and from the area around the former Dinoseb and Guthion tanks. The excavated soil and debris and the structural demolition material was disposed off-site at a Class I landfill.

From 1990-1991, THAN directed the installation of a SVE system in the former solvent storage area (13). The SVE system was installed in order to study its feasibility to remove xylenes and ethylbenzene present in the subsurface soils. THAN estimates that 6,500 pounds of xylenes and ethylbenzene have been removed by this SVE system since it began operation.

Starting March 7, 1988, THAN supplied bottled water to nearby residences and the elementary school to use for drinking water instead of their private well water (13). THAN also financed, starting in January 1990, the extension of the City of Fresno municipal water system to these residences. THAN provided three other residences with an alternate drinking water supply until an extension of the existing municipal water system was completed in mid-June of 1994. Currently, THAN monitors private wells in the path of the plume. When a private well becomes contaminated, it is taken off line and municipal water is supplied to the residence. THAN then extends its monitoring to private wells further down gradient.


On August 30, 1993, Jane Riggan and Marilyn C. Underwood, staff from CDHS, toured the perimeter of the THAN site. In addition to this visit, both Jane Riggan and Marilyn C. Underwood had visited the site several times dating back to 1991. Visits to the site have occured approximately three times per year since the August 30, 1993 visit, and no changes have been from the following observations have occurred.

The site, a 5-acre parcel, is defined as that part of the THAN property which was used for formulation and packaging of pesticides. Only four structures remain on-site: a one-story metal warehouse, a small office building, a tool shed, and a pump house (Figure 4). The warehouse is used to store soil samples collected during the remedial investigation. The office is used by the security and maintenance personnel, by the site caretaker, and occasionally by people involved in the site investigations.

The ground is paved from the entrance gate on McKinley, around the office building, and to the loading dock on the northern side of the one-story metal warehouse (Figure 4). The paved area is bermed on the southeast side, east of the metal warehouse, to collect surface water run-off from the northeastern portion of the site. The rest of the ground is rather barren and flat.

The site is surrounded by a six foot chain-link fence topped with three strands of barbed wire. We saw one gate and it was locked. There was no evidence that any trespassing occurs at the site. Shrubbery has been planted inside the fence along East McKinley Avenue. East McKinley Avenue, a two-lane country road, borders the THAN site on the north. East, west, and south of the site is an almond orchard, a total of 20 acres, also owned by THAN.

The land surrounding the site is used primarily for low density residential areas and for agriculture. The nearest residences are located east of the site along East McKinley Avenue, near the southwest corner of the site, and due south of the site. The majority of the residences that were built from 1977 to 1979 are located along Floradora Avenue, Olive Avenue, and Harvey Avenue, between Armstrong Avenue and Temperance Avenue.

Due south of the site, the land is subdivided into 24 parcels of 2 acre lots; some of the lots have only recently been developed.

The land south of the site, across Olive Avenue has been recently subdivided into 40 large lots. Only 12 of these lots have been developed.

An orchard is located north of the site, across East McKinley Avenue. A vineyard is east of the orchard. Between the orchard and the vineyard, a long driveway leads back to two residences. West of the orchard and east of Temperance Avenue is a residence. East and southeast of the site and the THAN almond orchards, the land is used for agriculture with a couple of residences located on McKinley Avenue.

An elementary school, the Temperance-Kutner School is located approximately 4,000 feet southeast of the site on the corners of Olive Avenue and Armstrong Avenue.

Mill Ditch is north of the site. Redbank Creek joins Mill Ditch approximately 1/2 mile northeast of the site. It is lined from DeWolf Avenue to Temperance Avenue where it is part of the flood control area, Redbank Creek Detention Basin.



For the 1990 census, the THAN site is located in census tract 59.01; however, many of the residents who have been affected by the contaminated groundwater plume live in the area defined by census tract 58.03 (Figure 5). According to the 1990 census, 6,272 people live in census tract 59.01 and 7,003 people live in census tract 58.03 (14). In census tract 59.01, approximately 8% are under the age of 6 years; 20% are 7 to 17 years of age; 58% are 18-59 years of age; and 15% are over 60 years of age (14). In census tract 58.03, approximately 15% are under the age of 6 years; 20% are 7 to 17 years of age; 57% are 18-59 years of age; and 7% are over 60 years of age (14).

The racial/ethnic makeup of census tract 59.01 is as follows: 86% white, 6.5% Asian, 1% African American, 1% American Indian, Eskimo, or Aleut, and 5.5% other (14). The racial/ethnic makeup of census tract 58.03 is as follows: 75% white, 8% Asian or Pacific Islander, 2% African American, 1% American Indian, Eskimo, or Aleut, and 14% other (14). The median family income in 1989, according to the 1990 census, for census tract 59.01 was $53,236; the median family income in census tract 58.03 was $36,268 (14).

CDHS estimates that there are 350 people living in the residences that were connected to municipal water by THAN and no longer use their private wells for personal use.

Land Use

Most important is the land use within the boundary of streets Fowler (west), Belmont (south), DeWolf (east), and Clinton (north) Avenues (Figure 2). Within this area and north and east of THAN, the land is primarily used for agricultural purposes and residences. Southwest of THAN along Temperance, Floradora, Olive, Harvey, and Belmont Avenues residences were built on two-acre lots prior to 1972. Twenty-four two-acre lots were developed due south of the THAN site starting in 1978. In 1980, a parcel of land located south of the site and south of Olive Avenue was subdivided into 53 two-acre lots; however, as of January 1994, there were only 12 lots with residences. There are two subdivisions located south west of the intersection of McKinley and DeWolf Avenues, due east of the THAN site: 8 lots of 2 to 2.3 acres subdivided in 1978 and 8 lots of 2 to 2.3 acres subdivided in 1988.

Temperance-Kutner School, an elementary school of the Clovis School District, is located on the southeast corner at the intersection of Olive and Armstrong Avenues. Approximately 200 children attend school at Temperance-Kutner School. The school was built in 1974.

The Fresno Air Terminal is located about 2 miles west of the site. A public golf course is located near the intersection of Olive and Fowler Avenues.

Natural Resource Use

The climate of the Fresno area can be characterized by hot, humid, summers and mild, foggy winters (1). The average summer temperature is usually 90F or higher with the average winter temperature about 45F. The rainy season occurs generally between October and April. The rainfall averages 10.52 inches per year.

The air flow near the site in the spring and summer months is from the northwesterly direction (1). During fall and winter months, calm, non-windy conditions predominate.

The soil on the THAN site is characteristic of the area and consists of well-sorted sands (1). This means that the near-surface soils drain well, are rapidly permeable, have low water-holding capacity, and are susceptible to wind erosion.

The site is situated on a gently southwest-sloping area of low relief (1). Surface water from regional storm runoff and subsurface drainage is conveyed westward and southwestward through ditches, canals, and modified creek beds operated and maintained by the Fresno Irrigation District and the Fresno Metropolitan Flood Control District. Drainage features within one mile of THAN include Mill Ditch, Redbank Creek, Temperance Ditch, and Fancher Creek (Figure 2). These drainage areas are the most likely potential sources of flooding in the vicinity of the THAN site.

Temperance Ditch was historically an open channel but between 1970 and 1979, the ditch was enclosed in an underground pipe (1).

In 1988, the Fresno Metropolitan Flood Control District proposed to build a 175-acre flood detention basin at the confluence of Redbank Creek and Mill Ditch, about 1/2 mile northeast of the site (1). The flood control district investigated the relationship between the Redbank Creek Basin and the THAN site and concluded that the operation of the detention basin for flood control purposes would not result in the further spread of pollutants from beneath THAN (15). Construction of the Redbank Creek Detention Basin was completed in the fall of 1990. This included the relocating and lining of Mill Ditch from DeWolf Avenue to Temperance Avenue.

Upon completing the excavation of the former landfill area in 1984, site grading was performed and two berms were constructed in order to divert and control stormwater run-off from entering the former landfill area (1). The water collected at one of the berms is pumped to a loading dock area located north of the existing metal waterhouse. The runoff that did not evaporate was formerly pumped to the adjacent orchard owned by THAN, but currently it is used for on-site irrigation purposes.

Following removal activities performed in 1989, the site was further graded (1). The grading focused on maintaining positive slopes to drainage courses on-site.


The site is within the eastern portion of the San Joaquin Valley, about ten miles from the westernmost foothills of the Sierra Nevada Mountains (1). The general movement of the groundwater in the vicinity of THAN is toward the southwest. The water-bearing zones underneath THAN have been divided into four zones (some of the zones having subunits):

A zone between depths of 19 and 50 feet below ground surface (bgs); B-zone between 57 and 77 feet bgs; C zone between 135 and 167 feet bgs; and 185 and 213 feet bgs. The A-zone became dry during the summer of 1987 because of climatic conditions and has only recently partially rebounded.

Within the vicinity of the THAN site, land east of Clovis Avenue is not within the incorporated area of the City of Fresno or the City of Clovis. Therefore, historically, the residences that have been built around THAN had private wells for their water sources. The well logs of the domestic wells indicate that the wells are screened from about 20 to 170 feet, the A, B, and C zones.

In December 1990, THAN paid for extension of the City of Fresno municipal water system to the area near the site and the hook-up of 64 homes and the elementary school to this system. These residences are located along Temperance, Floradora, Olive, and Harvey Avenues, southwest of the THAN site. An additional municipal water system extension to the area along Belmont Avenue between Armstrong and Fowler Avenues was completed by mid-June of 1994. THAN paid for the connection of three residences along Belmont Avenue to this extension.

Most of the residences that are now connected to the municipal water system continue to use their private wells for irrigating their lawn, gardens, and pastures, filling their swimming pools, and for pet and livestock drinking water.


There are two CDHS health outcome registries currently operating in the area of THAN. The state's cancer reporting system (CDHS California Cancer Registry) began collecting data for the region that includes the former THAN site and surrounding area in 1988 (16). The CDHS Birth Defects Monitoring Program began collecting data for Fresno County in 1986 (17). These health outcome registries are evaluated in the Public Health Implications section of this document.


The community health concerns related to the THAN site first became public in the spring of 1981 when several newspaper articles reported that families living near the THAN site were suffering from a number of unexplained illnesses that they associated with the "pungent fumes" coming from the pesticide formulating plant in eastern Fresno (18). In February 1981, a reporter spoke with families from fifteen homes around the THAN site who reported experiencing severe nose and throat irritation, headaches, and stomach cramps. Other symptoms included dizzy spells, coughing, and sores and skin rashes. In addition to the effect of the noxious odors on their health, residents were also concerned about whether their private drinking water wells had been contaminated by chemicals from the site. Officials acknowledged that the odors were "horrible" but assured residents that they were not harmful (19). Residents were also told that the groundwater contamination was not related to the THAN site.

The Epidemiological Studies and Surveillance Section (ESSS), of CDHS, first became involved with the THAN site when asked by DTSC to review groundwater monitoring data and the list of pesticides that had been handled at the site (20). On May 11, 1987, ESSS staff attended a community meeting where DTSC presented the Phase I workplan for addressing the clean-up of groundwater contamination and there was a discussion of the groundwater contamination at the Temperance-Kutner Elementary School located several blocks from the site. The school and residents close to the site were being supplied with bottled water, but there were no plans to provide an alternative water source for bathing, showering, and swimming. ESSS sent a cancer cluster investigation form to one resident who was concerned about excesses of childhood cancer in the area around the THAN site, but they never received the completed form. Other than that one follow-up, ESSS did not anticipate any further activity.

In the summer of 1987, T-K Neighbors in Action (T-K Neighbors) was formed by a concerned group of residents who wanted to address the issue of obtaining a clean water supply, either by installing granular activated carbon filters on domestic wells or by hooking-up to the city water. In addition, this group requested involvement in the development of the remediation plan for the clean-up of THAN and the alternative technology demonstration project. DTSC organized the THAN Community Advisory Committee consisting of concerned residents, community activists, government officials, and THAN representatives, which has been meeting regularly since February 1988. T-K Neighbors has been consistently involved in these meetings, representing the concerns of the near-by residents.

In the spring of 1989, DTSC again contacted ESSS (currently known as the Environmental Health Investigation Branch, EHIB) regarding residents' concern about increased health problems. EHIB staff met with the THAN Community Advisory Committee on August 30, 1989 (21). Ten members of T-K Neighbors attended this meeting and were upset to learn that it would probably not be possible to show a cause and effect relationship between exposure and health problems. The scarcity of air data made it impossible to estimate the exposure, and the low numbers of people made it difficult to draw any conclusions. However, EHIB staff agreed to review tumor and birth defects registry data to see if there were an increase of cancer and birth defects above what would be considered normal for the area. In addition, EHIB staff would provide information about some of the chemicals related to THAN and health effects that could result from exposure to them, which residents could use when speaking with their doctors.

During the fall of 1989, the dialogue between T-K Neighbors and EHIB staff continued. Although T-K Neighbors understood that a "cancer cluster-type" investigation would be fruitless, they continued to support the idea of a survey documenting adverse health effects of residents living in the area (22). They felt that this information might be useful in communicating with local health-care providers and generally expanding the knowledge about chemical exposures. EHIB staff did not think that a health survey would be instructive to local health care providers and instead suggested that local providers attend a regional training in March 1990 on environmental epidemiology and toxicology and on the health effects of pesticides (23). Forty-six health professionals including those in the medical, occupational, and environmental health fields attended the Fresno Pesticide Conference held on March 15, 1990.

Again in the fall of 1991, DTSC contacted EHIB because of the persistence of health concerns raised by T-K Neighbors. EHIB staff working on the CDHS/ATSDR cooperative agreement project talked with a T-K Neighbor representative about the public health assessment process as differing from a health study or health survey. Further, a public health assessment on the THAN site was not on the current workplan and thus it would be at least a year before the site could be addressed.

Marilyn Underwood and Jane Riggan of the CDHS/ATSDR cooperative agreement staff met with T-K Neighbors representatives on December 4, 1991, and further clarified the parameters of a public health assessment. They explained that environmental science is relatively young and at this time it is difficult to establish a cause and effect relationship between exposure and disease because of the lack of information on the health effects of low-dose exposure and the small numbers of people living around specific sites. However, one of the purposes of the public health assessment was to get a sense of community health concerns; documenting some of those concerns might prove useful in the future. Attendees proceeded to enumerate health concerns regarding respiratory problems, acute allergic reactions, skin problems, neurological symptoms, various cancers, birth defects, and health problems experienced by pets. In addition, they were worried about past exposures from air and water and about some of the chemical-handling practices at THAN. We sent T-K Neighbors a copy of Michigan's Citizen's Guide for Community Health Studies (24) pointing out that the document discussed the complexities of undertaking a community health study and what it can and cannot do.

The next contact with T-K Neighbors occurred on June 9, 1993, when Marilyn Underwood and Jane Riggan met with representatives of T-K Neighbors prior to a community meeting sponsored by DTSC to provide an update on site activities. The purpose of the meeting with T-K Neighbors was to review the elements and process of the public health assessment and to clarify how it differed from a health study. It was explained that the public health assessment would be reviewed by an ATSDR review panel who would make recommendations about follow-up health activities, including community and professional health education and various types of health studies and investigations.

The community expressed frustration and anger that their health concerns had not been taken seriously for over the last ten years, and they saw the public health assessment as just another "smoke-screen." CDHS staff explained that ATSDR gave credence to community health concerns and that is why the public health assessment actually had a section where health concerns were recorded. In order to attempt to capture the extent of the health concerns in this community, it was suggested that CDHS staff spend several days conducting informal interviews.

CDHS staff obtained a copy of the T-K Neighbors membership list to use as a basis for arranging the interviews. The response was positive, and CDHS staff were able to conduct fourteen interviews and gathered information on 20 people on September 1 and 2, 1993. Interviewees reported on symptoms and conditions experienced by themselves, family members, and/or neighbors. Prior to the interview, CDHS staff provided the following information: a brief description of ATSDR, the public health assessment process and the review process; the purpose for conducting the interviews; and the confidentiality of the information. We clarified that we were not conducting a health survey or investigation, but were trying to get enough information to adequately document the community health concerns. Even if the health assessment did not result in a health study, people's health concerns would be recorded and might be of value in the future as environmental science developed. The interviewees seemed to accept this concept.

The interviews were fairly open-ended, but we focused on several categories of information: 1) suspected exposures through air and water; 2) acute symptoms; 3) chronic symptoms; 4) diseases/diagnoses by doctors; 5) reproductive complications; 6) pet or farm animal symptoms or diseases; and 7) well water history. When people were describing how they were impacted by THAN when it was in operation, some of the most dramatic descriptions related to odors. Words such as "putrid" and "suffocating" were used. Odor descriptions ranged from "rotten egg smell" to "cooking 40 tons of broccoli or cauliflower," "skunk smells," "cooking cabbage and skunks together," and "dead, rotten animals." The odors reportedly were most noticeable during the night and on the weekends when it was hot and humid.

Interviewees described odors and dust in the air at various times between the late 1950s and 1981 while THAN was in operation. Several people said that they would wake up in the night choking and said that they couldn't take a breath. One woman said that the noxious odor would wake her up and make her feel sick. She would have to sleep with her head in the pillow. Several people asserted that it was not possible to stay outdoors when the odor was present, and they would have to keep their windows shut at night even in the very hot weather. During the last years of plant operation, one man stated that pungent odors occurred every three or four nights.

In addition to the odors, people reported site-related dust to be a problem. In 1958 and 1959 when the owners previous to THAN burned empty pesticide bags and waste from the site, people stated that the dust caused a constant haze and was so thick that it was like a heavy fog, and during the day they would have to use their car headlights as they drove by the site. It was necessary to clean off windshields before cars could be used. An unusual amount of dust would be present in homes, and residents had to close their windows in the summer because of the clouds of dust. Several people were also concerned about handling practices during plant operation and soil remediation. They reported that broken bags of pesticides were found along the sides of the roads and there was never any attempt to clean them up. The residents also reported that the trucks that were used to remove the contaminated soil were not covered, allowing soil to escape.

Respondents were also concerned about their exposure to contaminants through water. Several people commented that their plants were "pest free" when irrigated with well water but were plagued by bugs when they started using municipal water. One couple reported that when they first moved to the area, they suffered from diarrhea after drinking the well water and that it tasted bad. Others were upset by the high amounts of chlorine in the municipal water and regretted not being able to drink the well water. Another couple said that if the well water sat in a tub or sink for several days that it would turn thick and become a brownish-green color. In the early 1980s, several people were concerned enough about the safety of drinking well water that they took measures, including going out of state to get water samples tested, switching to bottled water, or buying their own carbon filter system.

Respondents reported a large variety of symptoms and diseases. These will be divided into three categories: acute responses, chronic symptoms, and diseases which were diagnosed or treated by respondent's physician.

Three people had severe acute reactions, each with its own constellation of symptoms: 1) One woman associated the development of her symptoms to a particularly horrible odor during a night in 1981. Over a period of several days, she developed huge welts on her legs which became so swollen that she felt like they were going to explode. She also became disoriented and developed an upset stomach and diarrhea. Her doctor diagnosed her as having a chemical reaction to medication, but she was not taking any medication at the time. She was in bed for approximately two and one-half weeks. 2) In 1981, while a man was working in his fields wearing a tank-top shirt, all his exposed skin started tingling. He had a strange taste in his mouth, his lips became numb, and his fingers became numb and so swollen that he could not bend them. He was referred to the Poison Control Center and it took several weeks for the symptoms to disappear. 3) The third case involved a man who was hospitalized two times in the summer of 1981 with blurred vision, stomach pains, delirium, severe weight loss, high fever, poor coordination, and numb hands and feet. One of his physicians suspected "possible lindane ingestion." It was recommended that he switch to bottled water.

Several people said that they had extreme difficulty breathing at a time when the odors were particularly strong and another person had an asthma attack. One woman reported that a strong odor one night caused her cheeks to tingle and her chest to become congested. One man stated that over ten years ago, he experienced an irregular heartbeat and dizziness. One woman was hospitalized for dizzy spells and tremendous stomach pains. Several men reported urinary tract infections. One was unable to get rid of his infection with antibiotic treatments until he switched to bottled water.

There were a variety of chronic symptoms listed by the respondents but the most prevalent involved: 1) respiratory problems including chronic lung problems and sinus, throat, and ear infections; 2) skin irritations and rashes; and 3) headaches. Several people related their breathing problems only to odors during the time when THAN was in operation, but others claimed that the problems continued after 1981. The chronic lung problems were primarily reported to be asthma, bronchitis, and trouble breathing. One woman said that currently she experiences a choking feeling and finds it difficult to breathe. She said that an inhaler helped ease the problem. In the mid 1970s when an eleven year old boy moved into the area, he developed recurrent breathing problems that were accompanied by hives with swollen eyes and a doubling of lip size. In the 1960s, a six year old boy had breathing difficulties accompanied by a high fever which resulted in his missing six months of school. After that he never seemed to be in very good health.

Several people complained about sore, irritated throats during the time of plant operation, often at the time of the worst odors. One woman asserted that her throat irritation has continued and that it is accompanied by a non-productive cough. Two of her children experienced the same symptoms. Several people complained of recurrent sinus infections that are not responsive to antibiotic treatment. Two children currently have constant runny noses. One of them also has frequent ear infections. Two people connected ear infections with the use of water in the early 1980s.

Skin problems were described in a variety of ways including sores, boils, chronic rashes, and skin discoloration. One woman related that since 1980 she has had a skin discoloration on her hand which would periodically itch, crack, and bleed. One man had a chronic rash except when he was attending college in another state. When he came home, the rash would always reappear. Another woman had medication for the chronic rashes on her arms, which disappeared when she left the area. Several people mentioned having skin cancer or pre-skin cancer, but most of them related their conditions to sun exposure.

Several people connected their headaches with the presence of odors while others say that their headaches have continued since 1982. Most of the gastrointestinal complaints of stomach pains and diarrhea were reportedly related to drinking well water. Some people noted a lack in energy and the feeling of being chronically tired.

Specific diagnoses or conditions treated by physicians covered a very broad range. Four people reported irregular heartbeat or tachycardia, a racing heart. They were all on medication. One boy received a diagnosis of hypertension in 1981 at age 15, and he is still on medication. One woman died of congestive heart failure at the age of 69. There were a variety of cancers including lung cancer, colon cancer (3 cases), rectal cancer, breast cancer, bone cancer, lymphatic cancer, pancreatic cancer, stomach cancer, brain cancer, and cancer of the appendix. Several people were diagnosed with skin cancer, but this was attributed to exposure to the sun. One person was diagnosed with lymphocytic leukemia and a twenty year old died of leukemia.

Several women had lumps in their breasts which were ultimately found to be benign. In the same family two women had uterine fibroid tumors and two had hysterectomies. One man who had stopped smoking 30 years earlier died from emphysema in 1990. One woman has ongoing problems with her liver where there has been degeneration, but according to her doctor, "it doesn't fit the usual pattern of cirrhosis." She also had bile duct pancreatitis and parathyroid surgery.

One man who had years of serious sinus infections that would not respond to antibiotics was recently diagnosed with common variable immune deficiency which results in an impaired ability to make antibodies. He receives gamma globulin every four weeks.

Two people under thirty were diagnosed with epilepsy and both are currently on medication. One woman has had Parkinson's disease for ten years, and another person was diagnosed with Tourrette's Syndrome.

Five families reported some type of reproductive complication. In two families, both the daughters and the daughters-in-law suffered miscarriages. In one family, a daughter who lived out of state had a miscarriage three weeks after visiting her parents who lived near THAN. Two sons in one family were not able to conceive due to what was called "erratic sperm count." T-K Neighbors described a lawsuit in the late 1980s that claimed that one man was sterile from exposure to DBCP.

Respondents had many health concerns related to their pets and farm animals. One man reported that, before using municipal water, his cattle were breeding every 16-18 months instead of the common breeding pattern of once a year. He said that many abortions were occurring at three to four months, and his calves were dying at a much higher rate. One man said that his bull was sterile and another said that his bull only produced one calf, which was born premature. Sheep were also reported to have higher miscarriages rates. At one farm the ewes exhibited enlarged mammary tissue and refused to breed. The rams were not very interested in breeding.

Several people stated that a number of their female dogs had cancer of the mammary glands. One female breeder was not very fertile. Several of the male dogs had cancer of the testes. One dog had stomach tumors and another died from "some type of cancer." Several collies died from hardening of the kidneys and two collie litters produced deformed puppies. When one family moved to the area, their terrier developed neurological problems and would go around in circles. One male dog died very quickly of leukemia at an early age. At least four families mentioned that their dogs had skin problems including dryness, loss of hair, and black spots.

Loss of hair also occurred in cats in two families and another cat had skin problems. Two of the cats in one family died from leukemia. One cat died of a jaw bone tumor at a year of age. One family reported that when they moved to the area they brought their pet goldfish. Once they moved to the neighborhood, no fish could last for more than a day in the water that came from the well.

The concerns discussed in this section are evaluated in the Public Health Implications section of this document.

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