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The Oklahoma Refining Company site, near the town of Cyril, Caddo County, Oklahoma, is approximately 160 acres. This Superfund site, which has been industrial since 1908, was operated from 1920 through 1984 as a crude oil refinery that produced gasoline, diesel fuel, and asphalt. Crude oil refining was restarted by Cyril Petrochemical Corporation (CPC) in 1993. The site was placed on the National Priorities List in June 1988. A Record of Decision (ROD), describing remedial selections for clean-up of the site, was issued in June 1992. Remedial activities are scheduled to begin in 1995.

Contaminants associated with the site include volatile organic compounds, semi-volatile compounds, heavy metals, polycyclic aromatic hydrocarbons (PAHs), and petroleum hydrocarbons. Heavy metals and PAHs are the primary contaminants at levels of health concern. During refinery operations, ambient air was likely to have been and could be a significant exposure pathway for on-site workers and off-site residents. Residents swimming in Gladys Creek downstream of the ORC site during refinery operations were likely to have been exposed to contaminants in surface water and sediment.

The Agency for Toxic Substances and Disease Registry (ATSDR) has concluded that the Oklahoma Refining Company site was a public health hazard during its past operation based on probable exposure during the release of wastes from the oil refinery process. The site is a public health hazard for on-site trespassers and on-site workers, if unprotected, due to waste in open waste pits, ponds, and traps. However, trespassing is unlikely at this time since a fence has been added between the active refinery and the pits, ponds, and traps. Potential human exposure pathways at the site are ingestion of or dermal contact with contaminated soil and waste sources. Although potential use of groundwater for drinking water could also pose a public health hazard, contaminated groundwater has not been and is not being used for drinking water.

ATSDR recommends that the site remain off-limits to the public and that residential yards adjacent to the site be sampled for heavy metals and PAHs. Workers should be provided with adequate personal protective equipment during remediation. Air quality should be monitored both on and off site during remediation. Since the refinery is active, air monitoring should include some pre-remedial monitoring to establish background air quality.

Health concerns conveyed by the public to ATSDR included brain cancers. Brain cancer is not a leading cause of mortality in refinery workers exposed to petroleum products and other refinery products.

ATSDR's Health Activities Recommendation Panel (HARP) determined that community health education was needed for area residents regarding health hazards of on-site contaminants that they may come in contact with when trespassing on the site. The Oklahoma State Health Department has prepared a fact sheet describing the health effects of exposure to site contaminants (Appendix IV). Some warning signs indicating hazardous chemicals have been posted by EPA.


A. Site Description and History

The Oklahoma Refining Company (ORC) site consists of approximately 160 acres near Cyril, Caddo County, Oklahoma (Figure 1, Appendix I). The ORC site is bounded by residential and commercial areas to the west, U.S. Highway 277 to the north, Gladys Creek to the east, and an unnamed tributary of Gladys Creek, private Indian lands, and city property to the south (1).

The site is believed to have operated from 1908 through 1920 as a gasoline stripping plant (1) and from 1920 until 1984 as a crude oil refinery. ORC purchased the site in 1978 and abandoned it in 1984 after declaring bankruptcy. During operations at the site, wastes generated from the oil-refining process were placed in more than 100 surface impoundments, many of which were unlined. Some of the wastes also were tilled into the soil as part of a land-farming operation (Figure 2, Appendix I).

A number of surface impoundments were used when the ORC facility was operating, including a lime soda storage pit, acid waste pits, temporary slop oil ponds, wastewater storage pits, sludge traps, and other miscellaneous ponds (Figure 2). The traps lie in an old, unnamed tributary of Gladys Creek and provide a means of stormwater runoff for both ORC and the town of Cyril. A plume of light nonaqueous phase liquids (LNAPLs), including hydrocarbons, is floating on the groundwater to the south of the refinery. There is also a plume of LNAPL floating on the groundwater north of Highway 277 (Figure 3, Appendix I). Contaminants associated with the site include volatile organic compounds (VOCs), semi-volatile compounds, heavy metals, polycyclic aromatic hydrocarbons (PAHs), and petroleum hydrocarbons.

ORC abandoned the southern and eastern parts of the property in 1986. An area at the site containing tar pits was purchased by a separate company. Pitch from the tar pits was removed and shipped to a company that sold it for use as road asphalt and roofing material. Sales of the pitch were eventually stopped because it was not known whether the pitch was contaminated.

The Cyril Petrochemical Corporation (CPC) purchased the refining equipment and the part of the site where the equipment was located in January of 1987. CPC sold the refinery to Cayman Resources in August 1991. Apparently, Cayman Resources owns the refinery but CPC currently operates it. CPC restarted refining operations in 1993. The ORC site is now divided into an active northern portion, where the refinery is located, and an inactive southern portion (Figures 4 and 5, Appendix I).

The ORC site was placed on the National Priorities List in 1988. The Oklahoma State Department of Health (OSDH) and the U.S. Environmental Protection Agency (EPA) conducted a remedial investigation and risk assessment for the ORC site. The remedial investigation was conducted between October 1989 and April 1991 (1). A removal action, completed in September 1991, included collection and storage of waste-sheen materials from the separator lagoons, erection of additional fencing and warning signs, and reparation of existing bird-netting (2). The Agency for Toxic Substances and Disease Registry (ATSDR) completed a preliminary public health assessment in 1990. An updated version of the public health assessment was forwarded to EPA and the Oklahoma State Department of Health in April 1993.

EPA issued a record of decision, dated June 1992. Some of the selected remedies included in-situ bioremediation of organic sediments, in-situ stabilization of inorganic contaminated sediments followed by capping, removal of all on-site surface water from impoundments, and treatment of contaminated surface water in an on-site treatment facility, removal and recycling of petroleum floating on groundwater, containment of contaminated groundwater using interceptor wells, and excavation and recycling of asphaltic materials (3). Remedial activities are scheduled to begin in 1995.

B. Site Visit

ATSDR and OSDH conducted a site visit on March 8, 1989, and a preliminary public health assessment was completed in 1990. A second visit was made in November 1991 as explained below and an initial release of the public health assessment completed in April 1993.

On November 12, 1991, a public meeting was held by representatives of the Oklahoma State Department of Health (OSDH) and the Dallas Regional Office of EPA. An overview of the work completed as part of the remedial investigation (RI), feasibility study, and risk assessment required by Superfund was presented by OSDH. ATSDR representatives Laura Barr, Tina Forrester, and Carl Hickam attended the meeting to gather information from Cyril residents about site-related public health concerns.

A second site visit was conducted on November 13, 1991, by OSDH, EPA, and ATSDR representatives, Laura Barr and Tina Forrester. ATSDR toured the abandoned refinery area, impoundments, previous discharge points, and land farms. ATSDR representatives noted that on-site wells no longer in use had been abandoned or plugged with cement. Test wells and piezometers installed during the RI were noted, and remediation was discussed. Initial contacts were made for collection of health outcome data and to verify that nearby residents were now drinking public water and had been while the refinery was operating.

During the site visits, ATSDR staff observed on- and off-site conditions, including land use in areas adjacent to the site; proximity of residential areas to the site; ease of site access; presence of on-site physical hazards, and general physical characteristics. Specific observations made by ATSDR are discussed in appropriate sections of this public health assessment.

EPA and OSDH have been working on site to reduce imminent threats to public health and the environment. ATSDR has received updates on site conditions through these agencies and has incorporated updates in appropriate sections of this public health assessment.

C. Demographics, Land Use, and Natural Resource Use


The Oklahoma Refining Company site is in southwestern Oklahoma, approximately 75 miles southwest of Oklahoma City (1). The ORC site is adjacent to the eastern part of downtown Cyril, which is a sparsely populated rural town. Cyril's population in 1990 was 1,072, down from its 1980 population of 3,717. That decrease (about 71%) apparently resulted from the lack of jobs following the closing of the refinery. The nearest residences are in Cyril, about 30 feet west of the site boundary. Land in downtown Cyril, immediately west of the site, is used for commercial, office, and industrial purposes (1).

Land Use

Agriculture in the site vicinity includes cultivation of cotton and milo and cattle ranching. Agricultural areas are east of the site. Gladys Creek was used for irrigating farm land before 1980. Other creeks downstream of ORC are currently used for irrigation. The Burlington Northern Railroad runs through the ORC site (1).

Natural Resource Use

A rodeo area is within a half mile of the site, just beyond the southern border. Other recreation in the site area includes fishing and swimming in the Little Washita River and Gladys Creek. Gladys Creek flows into Chetonia Creek, which flows into the Little Washita River, which is approximately 1.5 miles south of the ORC site. Gladys Creek forms the eastern border of the site and an unnamed tributary to Gladys Creek forms part of the southern border of the site. Brown's Pond is located on Gladys Creek (1).

The City of Cyril obtains drinking water from a rural water district. The rural water district obtains water from numerous wells northwest of Cyril. The closest public well is 20 miles northwest of the ORC site. Before December 1990, Cyril obtained drinking water from wells screened in the Rush Springs Sandstone aquifer, 2 miles north of the ORC site. Use of that water was discontinued when it was found to be contaminated with chlorides. The chloride contamination was not attributed to ORC because the wells are upgradient of the site (1). Outside of Cyril's municipal system and within a three mile radius of the site, there are approximately 104 wells used for domestic purposes, 7 wells used for irrigation, and 15 wells used for livestock watering (4). These wells are in the Rush Springs Sandstone aquifer (4). There are two private drinking water wells within a mile of the site. The closest private well is a quarter mile east of the ORC site. The City of Cyril has a well immediately south of the site that is currently being used as an industrial water source (4).

D. Health Outcome Data

Health databases are useful in determining whether health effects, such as cancer and birth defects, occur at a higher rate in specific areas. In 1991, OSDH began collecting data for cancer and birth defects registries. Incidence data are incomplete at this time. The potential of the contaminants of concern at the ORC site to produce cancer or birth defects is discussed in the Toxicological Evaluation of the Public Health Implications section of this public health assessment.


ATSDR staff contacted the city chief of Cyril, the Caddo County Sanitarian, and OSDH to determine if health concerns related to the ORC site had been expressed by residents or public health officials. No specific complaints or health concerns related to the ORC site were reported.

One resident expressed concern at the public meeting on November 12, 1991, that two cases of brain cancer might be related to past off-site exposures to site-related contaminants. That concern is addressed in the Public Health Implications section of this public health assessment.

Copies of the Oklahoma Refining Company Public Health Assessment were placed in two repositories, the Cyril Senior Citizens Nutritional Center and the Oklahoma Department of Environmental Quality for public review. During the public comment period, from October 30, 1994 to November 30, 1994, no public comments were received on this assessment.

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