PUBLIC HEALTH ASSESSMENT

KERR-MCGEE REFINERY SITE
CUSHING, PAYNE COUNTY, OKLAHOMA

1. Proposed limits - For uranium and thorium, the value listed is the concentration in water for a lifetime mortality risk of one in ten thousand (1 x 10^-4). For bismuth and lead, the value listed is the concentration in water for 4 mrem effective dose equivalent per year assuming 2 liters daily intake.
2. Maximum contaminant level.

* This well was on former private property "on site" near Linwood and Deep Rock Roads, by the east edge of the site.
1. Proposed limits - For uranium and thorium, the value listed is the concentration in water for a lifetime mortality risk of one in ten thousand (1 x 10^-4). For bismuth and lead, the value listed is the concentration in water for 4 mrem effective dose equivalent per year assuming 2 liters daily intake.
2. MCL - maximum contaminant level.

1. Proposed limits - For uraniums and thoriums, the value listed is the concentration in water for a lifetime mortality risk of one in ten thousand (1 x 10^-4). For lead, the value listed is the concentration in water for 4 mrem effective dose equivalent per year assuming 2 liters daily intake.
2. Maximum contaminant level.

List of Tables

D1     On Site -- Completed Exposure Pathways
D2     Off-Site -- Completed Exposure Pathways (NonPropertyA)
D3     Off-Site -- Property A Completed Exposure Pathways
D4     Potential Exposure Pathways
NOTE: Identification of an exposure pathway in these lists does not imply that the exposure is substantive or that an adverse health effect will occur.

Appendix E--Overview of Radioactivity and Health

Elements are composed of tiny particles called atoms. Atoms are composed of smaller sub-atomicparticles. In the center of the atom is the nucleus which contains two types of sub-atomic particles: theproton having a mass of 1.673 x 10^-27 kilograms or a relative mass of 1 (1 atomic mass unit, amu) andcarrying a positive charge, and the neutron having a mass of 1.675 x 10^-27 kilograms, an amu slightlygreater than 1 and carrying no charge. All atoms of an element have the same number of protons in thenucleus. This is called the atomic number. Atoms of the same element having different numbers ofneutrons are called isotopes of the same element. This changes only the atomic mass. Uranium with amass of 235 and uranium with a mass of 238 are isotopes since each has the same number of protons(92) but differ in the number of neutrons (143 or 146, respectively).

Around the nucleus are very small negatively charged particles called electrons, with a mass of 9.11 x10^-31 kilograms. The electrons orbit the nucleus in cloud-like shells or energy levels and determine thechemical properties of the atom. When the electrons are arranged in their shells so that all availablepositions are filled, the element is very chemically stable. However, if electrons are removed and ionsare produced (ionization), it can cause the breakup of molecules or other deleterious changes within acell. The damage produced by successive ionizations, accompanied by some repair for certain types ofinjuries and by no repair for others, could become serious and produce injury to living matter.

The nuclear stability of an element, however, is a result of the balance of forces in the nucleus. Anatom that is unstable or radioactive will release energy (decay) in various ways to try to achievestability. New elements are formed after decay that may be stable or radioactive. Newly formedradioactive elements (daughter products) continue to decay until they become stable elements (end products).

Radionuclides are characterized by the type and energy level of the radiation emitted. Ionizing radiationemissions fall into two major categories: particulates capable of producing ions (e.g., alpha and betaparticles) or electromagnetic radiation (gamma and x-rays).

An alpha particle consists of two protons and two neutrons emitted from the nucleus of the parentelement (+2 charge). This emission reduces the atomic number by two and the atomic mass by four andproduces a new element. As in the example of uranium 238, the radioactive decay emits an alphaparticle and yields thorium 234 (atomic number 90) plus energy.

Each alpha emission has a characteristic energy release. The alpha particle has a comparably large sizeand, therefore, has a great ability to react or ionize other molecules but has very little penetrating power. Generally, they cannot penetrate a piece of paper or the outer layer of human skin. However, if inhaledor ingested, alpha particles react quickly in localized areas of soft tissues such as in the lungs or liver.

Beta particles carry a single negative charge. Radionuclides with an excess of neutrons in the nucleusachieve stability by beta decay (emission of a negatively charged particle resulting in a decrease in thenumber of neutrons but an increase in the number of protons by one with no change in the atomic mass). As an example thorium 234 (atomic number 90) emits a beta particle and yields protactinium 234(atomic number 91) plus energy.

Beta emitting radionuclides can cause injury to the skin and superficial body tissue but are mostdestructive when inhaled or ingested. Beta emitters can be similar chemically to naturally occurringbody elements and will tend to accumulate in certain specific tissues or organs (target organs). Forexample, strontium 90 mimics calcium and as a result accumulates in the bones. The health effects ofbeta particle emissions depend upon the function of the target organ, the radiosensitivity of the targetorgan, the quantity of radioactive material ingested or inhaled, and the retention time of the radioactivematerial in a specific organ or in the body. The beta emitting radionuclides at the Kerr-McGee Cushingsite are daughter products of natural uranium and thorium.

Gamma emissions are simply the energy released during nuclear transformations. This has been shownin the previous equations as "+ energy". Gamma and x-rays behave similarly but differ in their origin: Gamma emissions originate in the nucleus and x-rays result from energy level changes with the orbitingelectrons. The emission of gamma or x-rays does not change the atomic number or atomic mass.

Gamma radiation penetrates the body from the outside and does not require ingestion or inhalation todamage body tissue. Gamma radiation is not directly ionizing; that is, it is not the direct cause of tissuedamage in the body as are alpha and beta radiation. Gamma emissions, which have no charge, canpenetrate through a medium without interacting until, by chance, they collide with electrons or nucleiand can liberate charged particles. These charged particles then produce ionizations, and damage to thecell or tissue can be the result.

We receive gamma radiation all the time from naturally occurring radioactive decay processes going onin rocks in our environment, from radioactive materials naturally present inside our bodies, fromatmospheric fallout from nuclear testing or explosions, and from space or cosmic sources. Thiscontributes to what is called background radiation. Exposure to natural background radiation may contribute to a slight increase in the risk of cancer.

Radioactivity is measured in units of disintegrations per second (dps) called curies (Ci) or becquerels(Bq). One curie (the unit traditionally used) is equal to 3.7 x 10¹⁰ dps. One becquerel (the newInternational System of Units (SI) unit currently used) is equal to one dps. A picocurie (pCi) is amillion millionth of a curie (1 x 10^-12 Ci) and is commonly used to quantify radioactive material in theenvironment. One becquerel is equal to 27 pCi. These disintegrations are independent of the chemicalnature and the mass of the compound. The number of dps does not relate to the harmful nature of theisotope. A unit of exposure to ionizing radiation, roentgen (R), is the amount of gamma or x-raysrequired to produce ions in air under certain conditions. The unit used to describe the absorbed dose inany medium is rad or gray (Gy). One Gy is equal to 100 rad. These units still do not relate well to thedifferent types of radiation and how they react in the body. Since alpha particles are not verypenetrating, they transfer their energy in a very localized area and can produce greater injury for a givenabsorbed dose. The factor used to express the effectiveness of this linear energy transfer is called thequality factor, which is highest for alpha particles, and the lowest for gamma and x-rays. When theabsorbed dose in rad is multiplied by this quality factor and other modifying factors, the result is thedose equivalent expressed in rem, or sievert (Sv). (1 Sv = 100 rem)

External gamma measurements may be taken with a tissue equivalent measurement device whichrecords the dose in microrem, or with a device that records the dose in roentgen (R). For the purposesof this study one µR was assumed to be equivalent to one µrem.

For more information please consult the references used for this discussion:

ATSDR Toxicological Profile for Uranium, U.S. Department of Health and Human Services, ATSDR, Atlanta, GA, 1990

Shapiro J. Radiation Protection, A Guide for Scientists and Physicians. Massachusetts: Harvard University Press, 1981

Appendix G--Public Comments

The public health assessment was available for public review and comment in the local library for aperiod ending December 2, 1996. The comment period was published in the local paper, and noticeswere mailed to nearby residents. In addition, the document was sent to several agencies and persons. Specific comments -- except for those addressing grammar or punctuation -- and responses aresummarized below. Where appropriate, the text presented in this final version has been changed. Anypage numbers mentioned in the comments below refer to pagination in the October 16, 1996 publiccomment version of the document.

1. COMMENT: Property A is not part of the Kerr-McGee site and should be separated from it.

Response: See Comment 17.

2. COMMENT: On Page 3; the waste volume has been estimated to be closer to 400,000 cubicyards.

Response: The text has been modified.

3. COMMENT: On Page 8; Sandstone lenses of the Vanoss Group have been documented to occuras shallow as 10 feet below ground surface.

Response: The text has been modified.

4. COMMENT: On Page 10; The Cushing Public Works Department no longer discharges treatedeffluent into Skull Creek.

Response: The text has been modified.

5. COMMENT: Page 14; The subject well was resampled by ODEQ on July 18, 1995. Twosamples (from well and tap) were obtained. Both samples were analyzed for organic pollutantsand priority pollutant metals, which include lead. None of the pollutants exceeded PrimaryDrinking Water Regulations or health risk-based standards as set by the U.S. EPA.

Response: The text has been revised to reflect the lead concentrations.

6. COMMENT: Page 17; An explanation should be furnished distinguishing dose related (non-stocastic) and non-dose related (stochastic) health effects, since cancer is associated with non-doseeffects (stochastic).

Response: The appropriate explanations have been added to the text.

7. COMMENT: Page 17, Paragraph 1; Please specify if the organ damage is referring to dose ornon-dose related health effects. An explanation may also be in order that non-dose health effectsare documented at relatively high doses and rates. Moreover, due to radiation safety standards, therisk from low-level radiation is estimated from the high-dose cases. In addition, when referring tocancerous health effects, dose should be addressed in units of rem while non-cancerous effectsshould be in units of rads.

Response: The discussion of organ damage is a general discussion and ATSDR does notbelieve that further discussion is necessary. The commenter use of rem and rad, however, isincorrect. The Rem (replaced by the Sievert) is a dosimetric quantity describing both theequivalent dose (effective dose multiplied by a tissue weighting factor) or the committedequivalent dose, which is integrated over a specified period of time. This time is 50 yearsfor workers and 70 years for a member of the public. The Rad (now replaced by the Gray) isan equivalent dose calculated by summing the radiation dose to each tissue and multiplyingby the appropriate radiation weighting factor. Neither term pertains to cancer or non-cancerous effects. In general, the rem is used when a radiation dose is estimated frombiomodels. The rad is used when bioassay data and the amount of radionuclide present in atissue are known. ATSDR recommends that the commenter review the recommendations ofthe International Commission on Radiological Protection Publication 60.

8. COMMENT: Page 18; Since all radioactive material produces ionizing radiation of some type,the sentence in paragraph 2 should be revised to state: "...contain elevated levels of both ionizinggamma radiation and radioactive material."

Response: ATSDR does not see the need for modification. The contaminants at the siterelease both particulate ionizing radiation in the form of alpha particles and/or beta particles. In addition to the particulate radiation, electromagnetic radiation in the form of gamma orphoton radiation is released. Therefore, no specific changes are needed as the currentwording, "ionizing radiation" addresses all aspects of the emitted radiation.

9. COMMENT: Please specify the method (e.g., zip code or other) used in distinguishing populationas being Cushing or Stillwater residents.

Response: Zip code.

10. COMMENT: Page 21; Property A already has residential population.

Response: Text has been modified.

11. COMMENT: Page 23; The sentence should read, "Water samples obtained from that pond do notshow..."

Response: The text has been modified.

12. COMMENT: Page 23 and 24; These pages mention the Colby public water system. Pleasediscuss what that system is, where it is located, and who it serves.

Response: "Colby" is an error; it should have been "Cushing" and refers to the public watersystem serving the Cushing community. The text has been modified to reflect the correctname.

13. COMMENT: Page 45; In discussing the off-site sludges, please clarify whether they are believedto be from activities attributed to Property A or from the Kerr-McGee Refinery.

Response: The text has been modified to show that the sludges on Property A are believedto result from former refinery operations on that property.

14. COMMENT: Pages 53-57, Table C1 lists the range of contaminant concentrations in column 2. Please explain what is meant by the 'ND', in this situation.

Response: The List of Acronyms, which immediately precedes Table C1 has been modifiedto show that "1000D" means that the constituent was analyzed for but not detected and theassociated numerical value is the sample laboratory quantitation limit.

15. COMMENT: Page 114, Table D1; A future pathway should be designated as a potential completed pathway.

Response: The document has not been modified. There are differing points of view aboutdesignating future pathways as potential or completed. Our review of this table reaffirmsour choice to designate these as completed pathways. This choice is based principally on thefollowing:
1) The level of exposure associated with completed future pathways does not have to besubstantive. Exposure need only occur, even at nominal concentrations. For all the mediawhere contaminants occur presently, we believe at least nominal residual concentrations willexist for the foreseeable future, even where remediation is fully and satisfactorily completed.
2) We assert that the "present" ends today and the "future" begins tomorrow, and believethat exposure-related activities that occur today (the present) will also occur tomorrow (thefuture).
3) Thus, it's expected that today's (present) completed pathways will continue tomorrow(future) to be completed pathways--and for some undefinable further (future) period of time.

16. COMMENT: Page 118, Paragraph 1; The correct mass of a proton is 1.6725E-27 kg while thecorrect mass of a neutron is 1.6748E-27 kg. The sentence may need to be revised to state; " theproton having a mass of approximately 1 atomic mass unit (amu) and the neutron having a mass ofapproximately 1 amu...". A definition of atomic mass unit may also be in order.

Response: The appropriate changes have been made. The mass of the proton, neutron, andelectron were added.

17. COMMENT: Public health risks associated with Property A, which was never either owned oroperated by Kerr-McGee should be deleted from this report. The title of the assessment names theKerr-McGee refinery site. At the least it is confusing when potential health hazards associatedwith another site are addressed in a report dealing with the Kerr-McGee site, and it could result inclaims being wrongfully directed at Kerr - McGee.

Additionally, although it may be appropriate to mention the elevated levels of naturally occurringelements (e.g., iron and sodium) in groundwater and drinking water supplies as a potential healthrisk, they would best be addressed in a separate report. It's believed that some local residentsinterpreted the assessment as an allegation that Kerr-McGee is responsible for these potentialpublic health hazards.

Response: Here, and in Comment 1, ATSDR is being requested to address in a separatereport any issue that is not directly associated with the Kerr-McGee property and associatedactivities. We understand the commenter's concern that readers may incorrectly view Kerr-McGee to be responsible for actions and hazards that have other causes. However, forATSDR to competently address public health aspects of the community that might beaffected by the Kerr-McGee site, it is necessary to consider other plausible contaminant-related health issues that might also affect those same people -- perhaps in an additive orsynergistic manner. We believe that such information needs to be contained in a singledocument so the community can reasonably understand it. However, where practical, thedocument has been modified to especially identify site-related contaminants and issues andnonsite-related contaminants and issues..

18. COMMENT: Some statements alarm rather than inform. For example, on Page 1, the Summarystates, "the Kerr-McGee site is considered a public health hazard because...(emphasis bycommenter). The remainder of the sentence contains actions that would make the site a publichealth hazard;

"children and adults could be exposed...if"
"...areas are not adequately remediated as planned..."
"and are subsequently developed for residential use.

Read in full context, a person trained in technical issues may say that this sentence does not saythat the site is a hazard, rather it could be a hazard if a series of highly unlikely circumstancesoccurred in the future. However, local citizens can easily receive the impression that the site iscurrently a public health hazard! ATSDR does itself and Kerr-McGee a disservice in presentingits conclusions in such an alarming and misrepresentative manner.

This sentence could be equally accurate and more precisely describe the actual hazard if written more like the following:

The Kerr-McGee site does not currently present a health hazard to the public. However, ifKerr-McGee does not complete planned remedial activities, and the property is laterdeveloped for residential use, residents could be exposed in the future to contaminants andradioactive materials that might harm their health.

Response: Text has been modified to reflect concept presented in the paragraph immediatelypreceding this response.

19. COMMENT: In a Site Decommissioning Plan submitted in April 1994, Kerr-McGee proposed tobury some licensed radioactive material that exceeds existing limits for unrestricted use in an onsite disposal cell. Since then, the plan has been revised, and a contract has been executed with alicensed disposal facility to receive that material. NRC and ODEQ were notified of this change in September, 1996.

Response: Text has been changed.

20. COMMENT: ATSDR has recommended that dust control measures be implemented duringremedial activity. Instead, the assessment report should state that dust control measures have beenand are being implemented in all remedial activity currently being performed, and all that has beenperformed to date. Asbestos removal and radioactive soil cleanup have been performed and airmonitors have shown no measurable dust emissions. Dust control measures are being employedfor the ongoing acid sludge remediation and disposal cell construction. State-of-the-artmonitoring equipment is documenting the fact that dust control measures are effective.

Response: The recommendation has been deleted and the text has been modified to provideinformation about past and continuing dust control.

21. COMMENT: This report appears to be several years past due as it seems it was to be completed in 1991. Why such a delay?

Response: ATSDR published an initial release of the assessment (and met it's mandated duedate) in 1990 but subsequently decided that the document did not address key issues in anadequate manner. ATSDR deferred completing the assessment due, in part, to competingagency priorities and new site investigation and remediation information that impacteddocument content.

22. COMMENT: A resident expresses several contamination concerns:

A. The (site) area has been polluted heavily in Sections 22 and 27. Pit 4 has had someextremely hazardous materials deposited in it. The earth where the disposal cell is beingconstructed emits vapors that ignite.
B. Hazardous material extends 4 to 5 feet deep in several locations (off-site) beneath the water surface in the creek bed.
C. Drinking water from private well is contaminated.

Responses:
A. ATSDR, while conducting this assessment, has been aware of -- and has accounted for --the contamination in the site area, including the contamination in Pit 4. Based on thecontamination information reviewed, ATSDR is not surprised that there are materialsthat emit vapors that could ignite under certain conditions. The plan for constructingthe disposal cell is expected to include provisions for first removing any unsuitable soilor other materials, such as ignitable materials.
B. The shallow creek sediment sampling conducted to date does not appear to support aconcern that deeper deposits of highly contaminated materials are present.
C. The resident's well water was analyzed for a variety of metals, organic chemicals, andradioactive contaminants. Any contaminants detected were not at levels of public healthconcern. ATSDR has recommended agencies conduct annual sampling until there isassurance that the site will not influence well water quality.

COMMENT: One resident stated that most people will agree the ground water will be poisonousfor several years to come. I'm extremely concerned about my drinking water.

Response: ATSDR's evaluation of groundwater in the area of the Kerr-McGee site, showedthat the Kerr-McGee site was not contaminating that groundwater. ATSDR has evaluatedcontaminants reported in area groundwater data. Samples from a private well did find lowlevels of lead and iron. Since the private well was not being used for drinking water, no onewas being exposed. Water samples from another private well and from a public well foundelevated levels of iron, which exceed EPA's secondary MCL. Exceeding the secondaryMCL means that the water may taste or smell bad but will not be harmful to someone'shealth. In addition, while some public well supplies contained elevated levels of sodium, it'suncertain whether or not those levels were being drunk by people since the public water wasmixed with other water before being distributed to people's home. The elevated levels ofsodium might be a concern for people who are on a salt restricted diet. Please read thePublic Health Implication Section, under the drinking water pathway subsection for moreinformation about exposure to sodium.

COMMENT: One resident stated that over the years tumors, stomach problems, birth defects, andcancer were rampant in the community and asked whether or not the contaminants at the site couldbe responsible.

Response: ATSDR's evaluation of cancer statistics showed that cancer rates are not higherthan expected for women who live in Cushing. While the overall cancer rate for men inCushing was found to be lower than expected, the men in Cushing had a higher death ratefrom prostate cancer than expected. It's difficult to be certain of the results of the canceranalysis, however, because the number of cancers and the number of people in thepopulation studied was small. This evaluation of cancer rates cannot be used to determine ifthe Kerr-McGee site has caused cancer in people who worked there or who lived near thesite. The reader is referred to the cancer discussion in the Public Health Implication Section, Health Outcome Evaluation subsection.

COMMENT: One resident stated that he or she worked at Kerr-McGee, swam and fished in theponds, and hunted in the area. The resident wanted to know whether or not the fish, frogs, quail, and deer are contaminated.

Response: No information exists for contaminant levels in fish and game on the site; therefore, ATSDR cannot answer this question completely. From our evaluation of thechemicals that were detected on the site; no chemicals were detected that are known toaccumulate in fish and game to hazardous levels.

COMMENT One resident stated that they had worked at Kerr-McGee in the 1970s in variousactivities.

Response: It is not possible for ATSDR to draw firm conclusions about the health hazardsof workers exposed to chemicals while working at the facility. The reason is that ATSDRdoes not have historical information about the level of chemicals in air, soil, or drinkingwater while the workers were doing their jobs. Based on the level of metals found in thesludge pits, however, it does not appear that workmen were working with waste that washighly contaminated with inorganic metals and hence workmen are not likely to have beenexposed to inorganic metals that would have affected their health.

COMMENT: One resident was concerned about health effects since the resident has a child that was born with a birth defect.

Response: In ATSDR's evaluation of the chemicals and pathways of exposure associatedwith the Kerr-McGee site, we did not find any evidence that residents were exposed tochemicals that might cause birth defects

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