Oak Ridge Reservation: Public Health Assessment Work Group
Public Health Assessment Work Group
April 21, 2003 - Meeting Minutes
ORRHES Members attending:
Bob Craig (Work Group Chair), Kowetha Davidson (Subgroup Chair), Al Brooks, George Gartseff, David Johnson, James Lewis, Tony Malinauskas, LC Manley, and Charles Washington
Public Members attending:
Gordon Blaylock, Owen Hoffman, Tim Joseph, and Danny Sanders
ATSDR Staff attending:
Paul Charp, Burt Cooper, Jack Hanley, and Dee Williamson
Liz Munsen (phone)
Bob Craig called the PHAWG meeting to order and attendance was noted for the record.
The purpose of the meeting was to (1) report the Epidemiology Ad Hoc Group’s status with regards to obtaining health outcome data and review the recommendation prepared by the group, (2) present and discuss the comparison of ATSDR’s minimal risk level (MRL) and ATSDR’s cancer comparison value, and (3) receive an update on ATSDR’s response to the ORRHES’ comments on the Y-12 Uranium Release Public Health Assessment (PHA).
Epidemiology Ad Hoc Group’s Report and Recommendation
Presenter: James Lewis, ORRHES
James Lewis explained that the Epidemiology Ad Hoc Group is developing a recommendation associated with the evaluation of some of the state’s cancer registry data. Mr. Lewis said that the group had primarily looked at the database established for Oak Ridge by ATSDR, which was created to identify various types of community concerns. The Ad Hoc Group evaluated the database to find community concerns that were associated with cancer.
James Lewis stated that he had also looked at the Health Information Tennessee (HIT) database. From this database, he identified the health issues that were a priority in Anderson County. Cardiovascular disease was listed as the top priority, and cancer was listed as the second priority in the county. Mr. Lewis said that there have been a lot of questions raised in the community about cancer and whether or not there were elevated cancer rates associated with exposure to contaminants. Mr. Lewis presented a summary of issues that had been taken from the community concerns database over the past two years. These issues included concerns about cancer in local areas, issues that related to exposure from the ORR, and questions about thyroid cancer. The Ad Hoc Group researched many of these issues and attempted to develop its recommendation based on these concerns.
James Lewis, Pete Malmquist, and Bill Murray worked collaboratively and found the New York State’s Cancer Surveillance Improvement Initiative on the internet. Mr. Lewis thought that this was a good example of what the community and the ORRHES needed to resolve these issues. Since there has been a lot of discussion related to cancer rates and whether the rates are elevated in the area, Mr. Lewis wanted to find an example that displayed what the group hoped to accomplish in its efforts. The New York data looked at various counties and established a ranking of the various cancer rates. Mr. Lewis used this example to show that the database expressed the health outcome data in the best manner–by associating the cancer register with areas of concern.
According to James Lewis, there have been a lot of questions about how to use these types of data. Mr. Lewis showed the PHAWG an example from an ATSDR presentation on an epidemiological study, where ATSDR went “from data to decision to actions.” Mr. Lewis suggested that they follow this same logic to form conclusions with the data that they receive. He provided an example of articles that were printed in The Tennessean with regards to Oak Ridge. He said that the newspaper had interviewed and collected data from several people in the community. In Mr. Lewis’ opinion, there were many “knee jerk reactions” to these articles, and that the newspaper had not necessarily taken actions that were focused in the right direction.
James Lewis wanted to avoid making mistakes that had been made in the past. He quoted a friend who says that “data should not be taken as intelligence until it has been evaluated by at least one knowledgeable person.” He added that once they collect these data from the state, some inferences could be made from the information. However, ATSDR will work with the state and will take all of these data through the complete process to reach a “decision point.” He added that they could not skip over steps (e.g., evidence of evaluation) before making decisions.
James Lewis stated that Toni Bounds, from the Tennessee State Cancer Registry, had discussed the utilization of these data previously and she had explained the limitations. Mr. Lewis said that several people have requested this information. Mr. Lewis explained that they cannot make inferences from these data or develop any conclusions without taking all of the confounders and other factors into account. However, the general public had asked this question and that was why the group was asking the experts to look at these data.
James Lewis said that he had reviewed the Dose Reconstruction Study and looked at the data that were evaluated in the document. He thought that the study dealt mainly with mortality data. In addition, he said that Toni Bounds indicated that there might be some other studies that were not available at the time that the Dose Reconstruction Study was conducted.
James Lewis said that they looked at thyroid cancer in the New York state database. He said that Al Brooks gave Mr. Lewis a history about the counties in New York. According to Dr. Brooks’ analyses of the data, one area that was industrialized did not appear to have a higher rate. Thus, Mr. Lewis said that there was a lot to be gained from these types of data, but that they cannot be taken as raw data without supporting evidence.
James Lewis explained that the major focus of this effort was to take the existing data from the state of Tennessee’s cancer registry and to collect as much data as possible. Then, they will sort these data and allow the experts to review the information, make an assessment, and provide an overview of their opinion.
The Ad Hoc Group developed three draft recommendations for the PHAWG to present to the ORRHES. James Lewis presented an overhead of the recommendations:
Phase I. To address the community concerns about an increased rate of cancer in communities surrounding the DOE Oak Ridge Reservation, the Tennessee Department of Health (TDOH) will provide the ORRHES with a health statistics review of all data for all cancers in the state’s cancer registry for the following eight counties: Roane, Anderson, Knox, Morgan, Loudon, Blount, Raga, and Meigs surrounding the Oak Ridge Reservation, and an updated report of the cancer incidence rates (combine all years) for each type of cancer by county.
Phase II. There have been community concerns about increased rates of cancer in the geographic areas identified in the Public Health Assessment where exposure to hazardous substances may have occurred. To address these concerns, we request that the TN Department of Public Health provide cancer incidence data by census tract to ATSDR so that they will be able to conduct a health statistics review of the incidence of cancer in those identified geographic areas of concern.
Phase III. ORRHES requests that ATSDR do a health statistics review using the data provided by the TN Department of Public Health.
James Lewis explained that the Phase I recommendation was associated with the original question asked by the work group, which was to obtain county data that were related to the areas of interest. According to Mr. Lewis, when the state of Tennessee obtains funding, it intends to conduct something similar to the state of New York. Depending on the results of the state’s analyses, the PHAWG may recommend that the state conduct monitoring. Phase II of the recommendations addresses how they look at areas of interest in regards to the plume. Mr. Lewis said that the state had data, and that in some cases, there were data down to the census tract level. He explained that the state might share these data with ATSDR. ATSDR will then compile the data, try to create an “area” that matches the plume, and develop a statistical baseline to compare this to other areas (i.e., a state average for a particular area).
Owen Hoffman asked whom the epidemiologists would be who would be going through these data. Dee Williamson stated that she was from ATSDR’s Division of Health Studies and that she would conduct the health analysis and prepare the written report.
Owen Hoffman stated that it is well known that disease registries are poor indicators of specific contaminant-related health effects, especially considering all of the confounders that exist. He wondered what could be done considering the inability to pull for confounders. Dee Williamson responded that ATSDR would use the cancer incidence data to answer questions from the community about the current cancer rates in their areas. She explained that it cannot be linked back to exposure and that this is something that they have been discussing as a group. She said that Dr. Hoffman is correct; the registry does not provide information on other risk factors associated with cancer, which has also been discussed with the group. She noted that there are limitations with the cancer data, but because there is not a lot of existing information, this would at least answer some of the community concerns.
Owen Hoffman stated that he had looked at Tennessee data when preparing the Dose Reconstruction Study, and that one question remained after the report’s completion. He explained that, in general, the state of Tennessee had a lower incidence rate of cancer than the rest of the country. His remaining question was, “How much of this is just due to the fact that hospitals do not report it?” Dee Williamson replied that she did not know, but that this was something that they could ask Toni Bounds from the state cancer registry. She added that Dr. Bounds had said that the state was underreporting, but that she did not know the percentage. Jack Hanley commented that this is calculated on a national criteria score. Mr. Hanley explained that the percentage needs to be about 90 or in the mid-90s, and that the state of Tennessee’s criteria score was in the mid-80s. Thus, the state of Tennessee was not meeting the goals based on these national standards.
Al Brooks wanted to point out a few aspects of the New York data. He said that when the number of cases goes down to one or two cases of cancer in a county, then there is absolutely no statistical significance. He pointed out notes that were written on the bottom of the overhead that indicated that most of these data were based on less than 20 cases. Dr. Brooks said that with the exception of a few counties, these data were statistically insignificant for the entire state. He said that if the state was pulling all cancer data, then it was pulling 100 separate diseases. Thus, the ability to draw conclusions from any of these data will be reduced. He said that the committee needed to be aware that the chances were “pretty darn small” that anything significant would come out of this. Dr. Brooks added that they are not the first people to look at the Tennessee data and that if anything in particular was going to “jump out,” then it would have already been recognized.
Owen Hoffman commented that Al Brooks explained what he had tried to express earlier. Dr. Hoffman said that he had looked at these data and that, in general, the population of Tennessee had one-half the average incidence reporting rate than the rest of the country. He added that for African Americans, this was extremely low. He explained that the difference between African Americans and Caucasians was usually a factor of two, and it was rarely a factor of three. He said that for the state of Tennessee, this approached a factor of ten. Dr. Hoffman questioned to what extent this difference was just explained by disparities in reporting and in medical care.
Owen Hoffman told James Lewis that the Dose Reconstruction Study used cancer incidence data. Dr. Hoffman said that he was certain that the state would have data that were not available at the time of his study.
Jack Hanley commented that Owen Hoffman was referring to the iodine Dose Reconstruction Study, but that James Lewis was discussing the overall Oak Ridge Health Studies. This overall document included health statistics reviews that looked at the early days of mortality data.
Jack Hanley asked James Lewis if he had an overhead of the concerns that had been collected. Mr. Lewis displayed an overhead that came from ATSDR’s community concerns database, which showed some of the comments and questions that had been raised by the community.
Owen Hoffman raised a point that a lot of the variability that is seen in these disease registries, especially with the state of Tennessee, is related to the variation in reporting, as opposed to real, underlying differences in disease rates. Jack Hanley said that Toni Bounds had indicated this to the group.
Bob Craig stated that this had been discussed for several weeks. ATSDR has pointed out all of the shortcomings from using registries and that there was really no conclusion that could be drawn from these data. In addition, this would not indicate causation in anyway. However, as a committee, everyone agreed that they wanted to see these data; this was why they were trying to compile the data.
Jack Hanley added to Bob Craig’s comments. Mr. Hanley has been working with the Ad Hoc Group and he has mentioned the difficulty that exists with using these data to show causation. They need to look at the questions that they are trying to answer. The main question is to find out if there is an increase rate of cancer in the general area compared to the state. Mr. Hanley said that this question can be answered with a descriptive epidemiological study by looking at cancer incidence data and comparing it to the state for each county, and by comparing it by county and by each cancer. This can be answered in the PHA by using a health statistics review, which is Phase I of the Ad Hoc Group’s recommendations. Phase II deals with finding a geographic area of exposure. There are concerns that the countywide basis is too large and that small pockets of cancer would be missed. In order to address this issue, Mr. Hanley explained that ATSDR would look for health endpoints that are associated with a particular contaminant in a particular area.
Al Brooks commented that he had an issue with Jack Hanley stating that the question could be answered if a rate was greater or smaller. He said that there is a third case in statistics, in which there is no answer. He said that getting into individual cancers had been discussed, but that this would go back to the problems with the New York data. Mr. Hanley replied that Dr. Brooks is right; they could end up with just a few cases and would not know the answers. Dr. Brooks said that they could have zero, two, or three cases and the answer would be that they did not know. Mr. Hanley said that Dr. Brooks was correct, but that at least ATSDR could say that it had looked at the data. Kowetha Davidson commented that you cannot draw conclusions from these types of data and that they should not attempt to draw any conclusions.
Dee Williamson explained that they had discussed these issues in the past when they talked about criteria that would be evaluated (i.e., if there are less than 10 cases of cancer, then they may not look at these because the rates would be unstable). She said that they would establish what they will and will not look for before they begin the process. She added that you could not interpret unstable results.
Al Brooks noted that they were not taking into account the truth about small sample statistics, and that there is a strong indication not to use small statistics. Kowetha Davidson added that she has reviewed occupational studies that use descriptive epidemiology in which cases of cancer were not included because the numbers were too small and hence, conclusions could not be drawn.
Owen Hoffman stated that he had no objection to the comments made by James Lewis; he was only trying to offer information to the PHAWG. He explained that in 1998, he looked through the state’s registry and found a “hint” of an excess of thyroid cancer in the four counties around the ORR. He said that they put in all of the “cautionary” statements in the Dose Reconstruction Study, but that this left him with an unanswered question. He wondered how much of this apparent excess was due to more efficient reporting in the hospitals (within these four counties) with regards to the rest of the state, provided that the rest of the state seemed to be out of sync with the rest of the country. Charles Washington asked if Dr. Hoffman was saying that the quality of the reporting in some counties might be better than in other counties. Dr. Hoffman said that this was correct and that there may be some extreme discrepancies of thyroid cancer reporting. Mr. Lewis said that the state has indicated that they have more data than was available in 1998.
Al Brooks noted that in addition to recognition and efficiencies of treatment, there is a “self-appointed” local expert who claims that as a result of exposures in Oak Ridge, residents’ life expectancies have been reduced by 20 years. However, this is remedied by the fact that they receive such good medical care that they are brought back to the average.
Tony Malinauskas stated that they were trying to combat instances where someone said that there was a local doctor who claimed that there was an excess of thyroid cancer in Oak Ridge. Kowetha Davidson said that unless the local doctor knew what rates were in other areas, then the doctor could not make that type of determination. Dr. Malinauskas replied that this doctor could be receiving all of the thyroid cases in Oak Ridge. Dr. Davidson added that he could be receiving all of the cases from Oak Ridge, but not from any other area. Dr. Malinauskas said that there were two questions that needed to be answered in this scenario. The doctor said that there was an increase, so you would want to determine if there was an increase, but you would also want to find out what caused the increase. A health statistics review could answer if there was an increase compared to the rest of the state, but he was not sure that they could answer what caused the increase.
Tim Joseph asked if they knew how far behind the state was in its data collection. James Lewis replied that the state was about two years behind. Dee Williamson said that ATSDR conducted another analysis in Tennessee in 2000 and she believed that the state had data up to 1998. Jack Hanley asked Ms. Williamson how they could quantify or measure the discrepancy if Anderson County was compared to the rest of the state. He also asked if Ms. Williamson thought that the state had information on how often cases were reported and what was the quality of the state’s data. Ms. Williamson replied that she did not know, but that she could ask Toni Bounds. She added that every limitation that has been raised would be included in the report.
Owen Hoffman explained that Joe Hamilton, who reviewed the work in the Dose Reconstruction Study, commented that certain counties had a higher incidence rate than the rest of the state because of an absence of African Americans. Dr. Hoffman wanted to examine if this was an issue, and if the reason was because the reported incidence of thyroid cancer among African Americans was low enough that it had a noticeable effect on the overall incidence rates. Dee Williamson said that when they adjusted for rates, this issue would be taken into account.
Owen Hoffman asked how far out the radius of the plume would be considered. James Lewis replied that they had a map that reflected the identified area, and that he believed that the map was taken from the Dose Reconstruction Study. Mr. Lewis added that Gordon Blaylock helped the PHAWG draw the area of interest, which has been voted and agreed upon. Dr. Hoffman said that it looked as though the area covered the major counties of concern and that it expanded beyond 10 miles. He said that this raised an issue because with a contaminant, such as iodine 131, it was the milk distribution network that determined the dose, not necessarily the atmospheric plume. Dr. Hoffman added that this region was so large that he did not think that there would be a problem. Jack Hanley explained that ATSDR tried to narrow down the area in the health assessment. He said that before ATSDR would move ahead on this, it would work with the PHAWG and ORRHES to determine the geographical areas. Dr. Hoffman said that this was a large area. Mr. Hanley replied that the area covered most of the plumes for all of the contaminants of concern.
Kowetha Davidson commented on the three draft recommendations. She said that the first recommendation stated that the TDOH would conduct a health statistics review, whereas the third recommendation stated that ATSDR would conduct a health statistics review. She asked which agency would conduct the review. James Lewis responded that these recommendations included a “default mechanism” because the state sometimes claims that it does not have the money to fund these types of projects. Mr. Lewis said that the “first line of defense” was to ask the state to conduct the review. If the state failed to take action, or if the process seemed to take too long, then they would like to obtain the raw data and have ATSDR conduct the analysis. Jack Hanley explained that during a discussion with the Ad Hoc Group, he told the group that ATSDR could conduct Phase I of the recommendations. However, the members of the group discussed the issue and thought that the state should already be evaluating these areas on a regular basis. A meeting participant asked Mr. Hanley what he meant by “areas.” Mr. Hanley said that he was referring to the counties. The participant asked if the state did this for every request that was received from Knox, Loudon, and other counties that have an industrial plant. Mr. Hanley replied that anyone who made a request would receive the data.
Kowetha Davidson asked if the state was prepared to conduct a health statistics review in the next year. She suggested that if the state did not know when it could conduct this analysis, then the state should give the data to ATSDR to conduct the health statistics review. Dee Williamson explained that they were going to give the state a chance to conduct the review, but that they expected that the state would give the data to ATSDR. However, they were going to give the state a chance to respond. James Lewis replied that he had made some preliminary contact with the state, and at one time, there was an indication that the material would be received within a couple of weeks. Although, this has been put on hold because the state has had to work with small pox and other issues. Mr. Lewis added that they needed a formal recommendation in writing and that this was the first attempt to do so.
Owen Hoffman asked why the process was not expedited by asking the state for a full Phase I and Phase II to occur concurrently, and that there was no reason why ATSDR could not look at the data simultaneously with the state. James Lewis replied that this was the protocol to obtain information from the state, and that they needed to have the request in writing.
Kowetha Davidson was concerned about Phase III of the recommendations. She thought that it would be confusing to have the same request from two different agencies. James Lewis said that they had intended to prepare a cover letter that would explain the recommendations. Dr. Davidson commented that the cover letter would not be in the minutes, and thus, it would not be included. Dee Williamson explained that the letter to the TDOH would have to provide the specific counties or census tracts that they would want to look at and that it would have to be very precise. Ms. Williamson said that they would have a certain time period for the state to respond with the data, and that if the state did not respond within that time, then the data would be given to ATSDR. Dr. Davidson thought that a specific timeframe should be put into the recommendations. Mr. Lewis agreed with Dr. Davidson. Tony Malinauskas suggested that they “negotiate” a time limit instead of “setting” a time limit.
Tony Malinauskas made a recommendation to the PHAWG that Phase III of the draft recommendations be worded as follows: “In the event that the Tennessee Department of Public Health cannot conduct the health statistics review in a timely manner, then ORRHES requests that ATSDR do it.” Bob Craig asked for the motion to be approved, and it was unanimously approved.
David Johnson asked if the letter would be sent to Toni Bounds. Bob Craig said that Mr. Johnson was correct.
Owen Hoffman inquired if it was more beneficial to have the state and ATSDR both look at the data until there were redundancies within their analyses. James Lewis replied that there has been some discussion by the state that it does not have a lot of funding, but that it intended to obtain the data. At one time, the data were supposed to have been sent electronically, but they were not.
Presentation and Discussion of ATSDR’s Minimal Risk Level and Cancer Comparison Value
Presenter: Paul Charp, ATSDR, and Jack Hanley, ATSDR
Jack Hanley explained that this presentation has been given on previous occasions. However, comments received on the first draft of the Y-12 Uranium Releases PHA indicated that clarity was needed on the comparison values used by ATSDR in its health assessments.
Paul Charp added that there have been several presentations on how ATSDR would conduct its radiation screening. Over its history, ATSDR has established MRLs, which are for noncancer screening. When the agency established one of its toxicological profiles on ionizing radiation for external exposure (on an annual basis), the Federal Facilities Assessment Branch decided to use an MRL. However, since the MRL was for noncancer screening, ATSDR needed a comparison value to screen for cancer, since ionizing radiation was a known carcinogen. Dr. Charp noted that the key word is “screen;” this is not a number that is set in stone, but it is a value whereby numbers can be assessed to see if additional evaluation is needed.
Paul Charp presented an overhead to the PHAWG. He explained that ATSDR developed this flow chart to show its process of estimating dose-based screening values. Dr. Charp said that the overhead was “2 of 2” and that the first overhead showed how ATSDR would estimate the total dose, which included the intake by ingestion or inhalation of biota, water, soil, air, and other media, and external exposure to derive a total dose. The estimated total dose would then be compared to the MRL, then to the background, and then to the screening value. If the dose was greater than the MRL, then ATSDR would evaluate the level that the dose exceeded the background. If the dose was not above the background, then ATSDR would determine that there was no health concern.
Paul Charp explained that, according to the National Council for Radiation Protection and Measurements (NCRP), the average background in the United States is 360 millirem (mrem). At this level and below, there would be no apparent health concern. If the level detected was above the background level, then further evaluation would be required. In this case, ATSDR would use site-specific conditions, weight of evidence evaluations, and epidemiological studies to determine if the level was at a level of health concern. If the value was a health hazard, ATSDR could issue a public health advisory. The agency has issued about 30 public health advisories, five of which were associated with radiological sites.
Paul Charp presented an overhead that showed a report conducted by the General Accounting Office (GAO) in 2000. In this report, the GAO evaluated the radiation standards across several agencies, and also interviewed a large number of scientific experts in the field of radiation health and radiation safety. The GAO’s consensus was that effects from radiological-induced health hazards could start occurring at any dose above 5,000 mrem. Dr. Charp noted that these health effects were well verified. The summary of the GAO report was that the range of effects were “somewhat verified” between 5,000 and 10,000 mrem. Thus, the GAO could not conclusively prove that increased radiation exposure between 5,000 and 10,000 mrem caused adverse health effects. In addition, the GAO stated that anywhere below 5,000 mrem, the range of assumed risk could assume one of four different dose response curves or any incremental risk values; this is similar to the findings in the Biological Effects of Ionizing Radiation (BEIR) III report. The BEIR III stated that the response could be a linear model, hormetic, lower risk, or even a higher risk; a higher risk is considered more dangerous than a linear no-threshold.
Paul Charp presented information that he had located in ATSDR’s Federal Facilities Information Management System (FFIMS). The information was on ATSDR’s MRL for noncancer, which is 100 mrem/year over 70 years and is equivalent to 7,000 mrem. The scientists who developed the toxicological profile on ionizing radiation based this MRL on the association that they could not find any noncancerous health effects related to exposures to background radiation; this was the no observed adverse effect level (NOAEL). Because of human variability, the nominal background was divided by a factor of three, and it was rounded down to derive the value of 100 mrem/year.
Paul Charp continued that an MRL for internal radiation has not been developed for the isotopes that ATSDR has looked at thus far, which included uranium, thorium, plutonium, radon, strontium, cobalt, and americium.
Paul Charp explained that the supporting literature for selecting the 5,000 mrem was the toxicological profile on ionizing radiation, which looked at several studies. In addition, ATSDR had considered using other doses for the cancer screening. It looked at the EPA cleanup level, which is 15 mrem/year. This level is based on radiation list models and Superfund guidelines. The number is a risk-based number of one excess cancer, in a population of 10,000,000, per mrem of exposure, and over 70 years; this 15 mrem/year equals about 1 roentgen equivalent man (rem) of exposure.
Paul Charp explained that ATSDR had thought about risk-based as it relates to causation. However, this turned out to be more of a judication of compensation claims for legal terms. In order for someone to qualify for this, they had to have the disease prior to filing the claim. In addition, there had to be a correlation between the medical and scientific knowledge, and the relationship between radiation and cancer risk. This led to ATSDR’s use of the 5 rem for the Y-12 Uranium PHA.
Paul Charp presented an overhead that ATSDR has been working on and it has been included in the Y-12 Uranium PHA. The figure showed ATSDR’s screening and dose limits as they compared to typical doses from ionizing sources. On the right hand side, there were descriptions, such as 1,000 mrem for a cat (CT) scan above background. There was also a nuclear medicine cardiac stress test, which fell around 2,500 mrem above background. Dr. Charp stated that these descriptions were taken from the Health Physics Society “Ask the Experts” website. On the left hand side of the figure, there was ATSDR’s acute MRL for noncancerous endpoints of 400 mrem per event above background. There were also NCRP’s public exposure limits and recommendations, as well as a literature review based on ATSDR’s evaluation of the 5,000 mrem over 70 years.
Owen Hoffman asked if Paul Charp was referring to “effective dose” when he discussed “dose.” Dr. Charp said that this was correct. Dr. Hoffman asked if the doses were in addition to background, and Dr. Charp said that this was true. Dr. Hoffman continued that this was inconsistent with any of the health risk criteria that they normally use in their professional work. He questioned ATSDR’s logic and said that he had corresponded on this issue, but that it had not seemed to have any effect. Dr. Hoffman added that doubling the background was not appropriate for indicating a minimum cancer risk. Dr. Charp said that he believed that it was, and that he also believed that there was sufficient information that “depending on what part of the country you are in, your background will double with no apparent increase in adverse health problems.”
Owen Hoffman spoke about the 360 mrem effective dose per year with regards to indoor radon. He explained that there is epidemiological evidence of residents’ indoor exposure levels that confirm that radon contributes to increased levels of risk in nonsmokers. According to Dr. Hoffman, about 30 percent of lung cancer in nonsmokers is radon-contributed and that radon is the major source of background radiation. The National Cancer Institute and the National Research Council also recognize radon as the second leading cause of lung cancer. Paul Charp said that he did not disagree with anything that Dr. Hoffman said. A meeting participant asked which statements Dr. Charp did not disagree with. Bob Craig clarified that Dr. Charp did not disagree with Dr. Hoffman’s comments about background radiation, but that Dr. Charp still said that he did not believe that the doubling of 360 mrem was a health concern. Dr. Charp noted that Dr. Craig was correct; he did not disagree with Dr. Hoffman’s statements that radon was considered a cause for increased lung cancer by the U.S Environmental Protection Agency (EPA).
Owen Hoffman asked if the GAO used the term “cumulative effective dose.” Paul Charp said that he would have to look back to see what the GAO called the doses. Dr. Hoffman explained that there was epidemiological evidence of radiological effects in utero down into 1,000 mrem for effective dose. For a 5,000 mrem total effective dose, the organ dose could be significantly higher. For example, a child’s thyroid would receive 100,000 mrem, which was well into the range of epidemiologically significant effects for both cancer and noncancer health endpoints. Dr. Hoffman continued that there were several single organs for which an effective dose of 5,000 mrem would be an organ dose of 100,000 mrem, and for some organs, it could be as high as 500,000 mrem. Dr. Hoffman was present at the PHAWG meeting to raise the issue that the use of effective dose was a “poor surrogate” for health risk. He added that if the numbers that ATSDR were proposing were to be organ doses, then he would not have a problem. However, Dr. Hoffman stated that he has a “professional issue” with the use of the effective dose for retrospective analysis. Dr. Charp replied that he can understand Dr. Hoffman’s concerns. He added that the Y-12 Uranium PHA lists the effective dose, but also lists the organ dose for the critical organs as proposed by the International Commission on Radiological Protection (ICRP).
Tony Malinauskas asked about when one organ dominates the exposure, if the sum of exposure and the sum of risk over all the organs would be approximately equal to the organ in question. He said that if they were approximately equal in their total risk, then it was no longer a valid approximation.
Owen Hoffman stated that he would be a proponent for risk-based decision making because ATSDR was trying to establish a risk below which public exposures would not warrant any further analysis. He understood that ATSDR was putting its limited resources into where the agency could do the most good for the public, which was a valid approach. However, he argued for a risk-based approach. Dr. Hoffman added that if ATSDR was going to use a dose-based approach, then it should be sure that the dose criteria used did not lead to a situation where cancer and noncancer effects could potentially occur.
Paul Charp made two comments in regards to Owen Hoffman’s statements. First, Dr. Charp noted that Dr. Hoffman said that ATSDR selected dose over risk, but ATSDR is not given a choice. Dr. Charp explained that ATSDR does not use risk numbers for any of its evaluations, and that this is the reason that they are called “health assessments” instead of “health risk assessments” or “risk assessments.” Second, Dr. Charp explained that when looking at doses to specific organs, other than the thyroid, it is not really clear what dose level constitutes a health risk. In fact, the ICRP even uses a dose limit of 2 rem for workers.
Al Brooks asked what the MRL stood for again. Paul Charp replied that this was the minimal risk level, the level at which there is no appreciable risk of adverse noncancerous effects over a specific duration of exposure. The MRL is noncancer-based. Tony Malinauskas stated that the risk level is also based on dose.
Owen Hoffman asked about values being used for noncancer and cancer health effects. Paul Charp responded that ATSDR separated the two and used an MRL and a cancer screening. A meeting participant asked if this was going to be applied to iodine 131. Dr. Charp said that it would not be applied to iodine 131.
A meeting participant said that it seemed to him that since they were handling the most sensitive organ separately (thyroid with iodine 131), this was more of an academic debate concerning the use of the dose level versus the risk level, rather than a debate over the crucial element of the process.
Gordon Blaylock asked about the difference in bone. Paul Charp responded that bone was .01. Mr. Blaylock asked if uranium goes to bone. Dr. Charp said that it did. Dr. Charp added that the most critical organ for nonradiological effects is the kidney.
Owen Hoffman stated that if a person had bone cancer and if that person had a bone dose equivalent to an effective dose of 5 rem, then the person (if the person was a DOE worker or an Atomic veteran) would be eligible for compensation.
A meeting participant asked what the exposure was for uranium. Paul Charp responded that if ATSDR had picked a screening level of 10 mrem in Scarboro, then the exposure would have been below that level.
Charles Washington said that the level of the radiation was actually organ specific. He added that they should determine the lowest level where an organ could be affected, as opposed to the entire body. Paul Charp added that this also depended on the isotope.
Kowetha Davidson said that if they used risk, then they would have to determine what risk level would be of public health concern. Charles Washington commented that this PHA was being written for people who have some knowledge about radiation and risk. He preferred to present the information as possible damage to specific organs. He added that the public would understand that if they received a certain dose, then they were at risk.
Owen Hoffman repeated that the reason he was at the meeting was because he did not believe that a screening level of 5 rem effective dose was protective of public health. He also repeated that he was at the meeting on his own time. Bob Craig said that they have heard several arguments regarding this issue and that he would like Paul Charp to continue with his presentation.
Owen Hoffman asked if Paul Charp was providing the MRL for external radiation.
Dr. Charp said that this was correct.
Owen Hoffman said that the EPA risk-based number given by Paul Charp could not be based on cancer incidence because if it was, then the number would be lower. Dr. Charp replied that for risk, the number that EPA uses is 5 x 10-4 for per rem, which is divided by 1,000. Dr. Charp said that this would be 5 in 10,000,000. Dr. Hoffman added that the risk of radiogenic cancer incidence was closer to a value of 1 in 1,000,000 per mrem of whole body radiation exposure (as a lifetime total). In the Dose Reconstruction Study, they used a risk-based screening criterion of one chance in 10,000 for a reasonably, maximally exposed individual. For radiation, the risk was the excess lifetime risk of cancer induced by cumulative exposures to all ORR releases. For exposure to single contaminants, a screening criterion of one chance in 100,000 was used. According to Dr. Hoffman, the proposed ATSDR value of 5,000 mrem lifetime effective dose is associated with a risk that is approximately 50 times higher than the risk level used for screening in the Oak Ridge Dose Reconstruction.
Owen Hoffman stated that the only aspect missing on the final figure in terms of dose is that 1 mrem/year over a lifetime is very close to what the EPA uses as an upper limit on its range of acceptable cancer risks (one chance in 10,000) in its Superfund assessment, and also similar to what the Oak Ridge Health Agreement Steering Panel (ORHASP) used for the Oak Ridge Dose Reconstruction. Jack Hanley replied that the Y-12 Uranium PHA included background to provide perspective. Mr. Hanley said that the bolded area, with the doses on the right, had 155 mrem over 70 years above background. He showed that for current concentrations from the last 5-8 years, the current dose was less than one mrem over 70 years above background. ATSDR added this diagram to communicate information regarding where these doses were in regards to other doses that were “out there.”
Paul Charp noted something for people who were familiar with the Task 6 Report. He said that the number that was summed in one of the tables in this report had equaled about 84 mrem/year for the cumulative effective dose equivalent, which was based on 52 years of exposure. ATSDR altered the number because it raised the exposure to 70 years. Thus, the dose was changed to 155 mrem over 70 years.
Tony Malinauskas asked if there were enough data available to go from dose-based to risk-based. Paul Charp responded that there were and that EPA uses a nominal risk of 5 x 10-4. Dr. Malinauskas asked if someone could explain why ATSDR uses dose models when dose models are not additive, but probabilities are additive. Owen Hoffman commented that EPA uses risk-based models, as well as the National Cancer Institute and the Department of Labor for compensation claims. Dr. Hoffman said that ATSDR “seems to be rather alone” with quantifying risk. Dr. Charp stated that the Nuclear Regulatory Commission (NRC) also takes this approach, but Dr. Hoffman said that the NRC does not conduct public health studies, as it is a regulatory agency. Jack Hanley noted that EPA uses its risk model of 15 mrem/year of background for cleanup levels because the agency is trying to set a “safe” level for any future land use. Whereas, ATSDR is trying to determine where the health effect would occur. Dr. Malinauskas asked when EPA decided what was and was not safe. Dr. Charp said that EPA bases its safe level for radiation on what is considered safe in other non-nuclear industries. Owen Hoffman thought that 15 mrem was a compromise and that it was not exactly risk-based. He explained that the Superfund risk range led to a dose level around the 4 mrem per year range (assuming a 70-year exposure duration), but that the NRC was proposing 25 mrem per year as its so-called “safe” level. To reduce the exposure level for 30 years and to make some compromise, EPA increased its acceptable dose level to 15 mrem per year, which translates to a lifetime excess health risk of nearly 5 chances in 10,000 for a lifetime risk of excess cancer incidence. According to Dr. Hoffman, these agencies are still arguing over which level is actually health protective over a person’s lifetime. Dr. Hoffman added that the issue was something that Paul Charp had addressed previously. He said that the question that should be evaluated was “from the standpoint of health effects or health risk, what is the radiation exposure level below which detailed further evaluation is not warranted.” Dr. Hoffman added that he believed that this should be addressed and that he thought that it should be evaluated based on anticipated risk rather than on effective dose.
Tony Malinauskas did not see the argument because risk is based on some dose. He continued that if you had a risk limit, then you automatically had a dose limit. In addition, Dr. Malinauskas stated that the question was whether you applied a dose limit for one organ or over the whole body. Owen Hoffman replied that the solution was to find a sufficient risk level that would warrant “no further investigation” and then to use a calculation to find the organ dose. Paul Charp said that this was essentially what the Task 6 report did. He explained that in this report, ChemRisk estimated the dose, and then for screening one and screening two levels, it took the total detriment value of the ICRP and multiplied the dose to obtain the screening value. If it was above 10-4, the report conducted further evaluations. According to Dr. Charp, the Task 6 report looked at cancer and noncancer detriment and non-detriment risk. He said that the report looked at “risk;” the report estimated the dose and multiplied it by .073 to obtain a screening value. Dr. Charp added that you needed a dose before you could have a risk.
Kowetha Davidson brought up an issue of safety factors. She stated that EPA has recently used scientific reasons for safety factors. However, initially EPA based its safety factors on policy instead of science. Dr. Davidson said that if 5 in 10,000 was picked as a regulatory level, then that was a policy decision. It was not a scientific decision because there was still a chance that 5 people out of 10,000 could develop cancer. This would not tell someone if they were going to get cancer. She thought that there needed to be a regulatory level that everything could be based on.
Jack Hanley gave an example from the last PHAWG meeting where they discussed mercury and its reference dose (RfD). He stated that EPA uses its RfDs to set clean up levels and that there is a 1,000-fold safety factor involved with these levels. Mr. Hanley stated that an RfD would be used to set a clean up level, but that it would not be used to determine where a health effect would occur. In order to find where a health effect would occur, they would have to determine the NOAEL or the lowest observed effect level (LOAEL) and evaluate if it is a health problem; however, you would not see if the level was protective of the most sensitive populations. Also, in regards to a previous statement by Owen Hoffman, Mr. Hanley stated that ATSDR has looked at the “probability of causation” issue. He said that Dr. Hoffman is correct in that for some of the doses, if you put a number into a calculator, people would be compensated based on their doses. However, ATSDR’s purpose is not to work out claims with patients, as the agency has a separate mandate.
Owen Hoffman replied that ATSDR was making the statement that if a person had cancer, then what was the chance that past exposure attributed to this illness. He said that if ATSDR was making these types of statements, regarding attributable risk – “what is the chance that past exposure may have caused the disease that you have today,” then this represented probability of causation. Jack Hanley replied that first of all, the person had to have cancer before the probability of causation could be calculated. Second, ATSDR deals with the broad public health, not with individual clinical cases. ATSDR’s policy for individuals is that it refers these people to a clinician for independent evaluation. Mr. Hanley added that ATSDR was not here to calculate risk and the probability of an individual getting cancer. Dr. Hoffman said that it was difficult for ATSDR to make transparent decisions because it was trying to “force the concept of effective dose” into a statement about public health risk.
Paul Charp responded that he can appreciate Owen Hoffman’s comments about dose versus risk. However, their “hands are tied” because ATSDR mandates that they conduct evaluations in dose instead of risk. Dr. Charp added that ATSDR was producing a new guidance manual that was going to be released, and he suggested that Dr. Hoffman send in his comments about using risk instead of dose. Dr. Hoffman hoped that his presence at this meeting would be regarded as his communication to the group and to ATSDR.
Jack Hanley added that for iodine and uranium, ATSDR will calculate individual organ-specific doses. Owen Hoffman responded that although this was “good,” it still baited the question about “what is an organ dose” with regards to its significance for public health. He said that it did not have to be equal to EPA’s levels or the levels used for the Dose Reconstruction Study; however, he would like to know ATSDR’s basis for setting its levels. Paul Charp replied that ATSDR based its iodine level on new information from several recent studies, such as reports from Chernobyl. Mr. Hanley suggested that he and Dr. Charp share these meeting transcripts with Allan Susten and other people at ATSDR who were working on the guidance manual. He said that he appreciated everyone coming to the meeting.
Update on ATSDR’s Response to ORRHES Comments
Presenter: Jack Hanley, ATSDR
Jack Hanley provided a brief review of the Uranium PHA process, which involves the ORRHES and the community. In November, the first PHAWG meeting was held to discuss the references and data sources that would be used. In early December, Paul Charp and Mr. Hanley presented ATSDR’s preliminary findings, and informal discussions were held until January. In early January, ATSDR presented its initial release, also known as the “data validation version,” to the PHAWG. The PHAWG provided comments, the comments were sent to the ORRHES at the last meeting, and then were forwarded to ATSDR. Since that time, ATSDR has been addressing the comments. Mr. Hanley presented the changes that ATSDR has made to the document based on the comments received from the ORRHES. The document is being released this week for public comment.
Jack Hanley presented overheads of some of the comments that were received and explained how ATSDR changed the document to respond to the following comments:
Body of text
- Show early on why Scarboro was the focus, and if there was no effect
seen there, then there is not likely to be an effect in the general
ATSDR clarified this is in the document.
- The Task 6 report uses a dispersion model to estimate where the highest
concentrations would have been off-site where there was an established
population. Scarboro was the location that would have had the highest
doses based on a very conservative model.
This was clarified and stated in the beginning and in additional places
within the document. The statements noted that based on the screening,
Scarboro was identified as a reference population, and that if doses in
Scarboro were not of levels of public health concern, then other areas
were not likely to be of concern either.
- More information is needed about natural background sources.
- Data in the report indicates only background levels and impacts that
all of this has had on Scarboro.
ATSDR developed some very clear statements in the summary and throughout the document to explain where the doses were found and compared these to the comparison values. In addition, it was made very clear how many times lower the doses were in Scarboro when compared to comparison values. In addition, ATSDR made a number of statements throughout the document about the impact that this may have had on Scarboro and its surrounding communities.
- The document needs clear, forcible statements.
- There was confusion about the screening values and MRLs.
- More quantitative information was needed on the front end, instead
of just qualitative statements that “there is no public health
In the summary and conclusions, ATSDR added and clarified
information about the comparisons used for each media and each of the
doses, which were used to estimate the total doses and organ doses.
- Clarify statements concerning the degree of conservatism that is used by ATSDR.
- Clarify enrichment issues.
Paul Charp discussed enrichment issues in further detail within the summary,
body of the text, and conclusions section of the document.
- Clarify findings.
ATSDR attempted to clarify and communicate its findings more effectively.
- Clarify the 5,000 mrem and where it comes from.
ATSDR attempted to clarify this by moving information
from Appendix F into a couple of locations within the document.
ATSDR added a discussion about natural background sources and used a thermometer graph to show the location of background, natural background doses, and where Scarboro doses compared to the natural background. In addition, Paul Charp discussed this in further detail within the document.
ATSDR tried to be as clear as possible. Mr. Hanley requested that people provide comments if they feel that additional statements are needed.
ATSDR went back and clarified the sections about MRLs and the comparison values (one is for cancer and one is for noncancer) and how they are used.
Summary and Conclusions
ATSDR tried to show the degree of conservatism of its screening values within the narrative and also by using visuals (e.g., thermometer graph).
Jack Hanley noted that the document might sound repetitive because the same statements were provided in the summary, in the body of the text, and in the conclusions. Mr. Hanley explained that there had been concerns that some people may read either the summary or the conclusions, but not both sections. As a result of these concerns, ATSDR provided pertinent information in several places within the document. In addition, ATSDR refined and addressed the comments about the MRL and how ATSDR justifies its use. Mr. Hanley said that the document did not explain the two or three different methodologies (risk-based, dose-based, and probability-causation) of data interpretation.
Jack Hanley mentioned a concern about the technical language used in Appendix C. Mr. Hanley explained that ATSDR went through and edited parts of this appendix, but that the technical language was not removed because the section was put into an appendix because of its language. Also, there were several editorial comments made and ATSDR tried to incorporate as many as possible. Mr. Hanley added that, as a result of these comments, the PHA is a much more effective document.
Tony Malinauskas wanted to pursue a statement that Jack Hanley had made in his presentation. Dr. Malinauskas said that Mr. Hanley had indicated that the point of highest exposure where there was a population was Scarboro. He recalled that some of the reports calculated exposure for an individual regardless of whether the person was surrounded by other individuals or not, and he added that some of these occurred in Union Valley. Mr. Hanley asked if he was referring to the other reference location. Dr. Malinauskas replied that he was not; these were calculated exposures for a person who experienced all exposures. He asked Mr. Hanley where this person would be located. Mr. Hanley responded that this information was in the overall report prepared by the ORRHES panel. Dr. Malinauskas asked if those numbers differed greatly from the Scarboro exposures.
Jack Hanley explained that he had also thought that this was confusing and that he was going to clarify this at the ORRHES meeting on April 22, 2003. He continued that pre-1990 was based on modeling uranium releases from Y-12 from the ChemRisk Task 6 report. For 1990 to the present, ATSDR used the Annual Site Environmental Report (ASER) for air and water data, the Florida A & M soil samples, and EPA samples. Thus, ATSDR used “actual uranium samples,” but the uranium could have come from any source. Tony Malinauskas said that ATSDR used a slightly different calculation than the other reports. Mr. Hanley continued that ATSDR used the most recent data over the last 8 or 10 years, depending on what were available. In this PHA version, ATSDR went to areas outside of Scarboro where data could be found. ATSDR used air monitoring data from a station by the museum that was operating in the late 1980s and early 1990s, and also found vegetable samples from a number of locations outside of the area. Mr. Hanley said that in the current analysis, ATSDR does not say that these data come from Y-12 because the data could have come from a variety of sources or could have been naturally occurring.
Tony Malinauskas asked if a “useful purpose” would be served if ATSDR translated the doses and exposures into risk. Paul Charp replied that it would be a simple step to take the dose numbers, multiply by a risk number, and obtain a risk. However, as Dr. Charp mentioned earlier, ATSDR’s policy is that “they don’t do risk.” Jack Hanley commented that if they came up with a risk value, then what would be considered a hazard and what would not be considered a hazard (e.g., 1 in 10,000). He asked if you took the dose and went to risk, then what would that risk number mean. He said that you would have to have a “line in the sand” that could be drawn to know what was a problem and what was not a problem. Dr. Malinauskas did not think that there was any argument over which was “technically the most correct.”
A meeting participant stated that he was trying to indicate that it was quite possible to show that the likelihood of winning the lottery was better than the likelihood of a person developing bone cancer as a result from exposure to uranium releases from Y-12.
Bob Craig asked if the ORRHES would receive the final PHA tomorrow. Jack Hanley replied that the public comment version would be given to the ORRHES tomorrow. Based on discussions with the Communications and Outreach Work Group (COWG), ATSDR prepared a “brief” summary of eight or nine pages that shows the comparisons, key issues, key tables, and pertinent figures. Dr. Craig asked if this was similar to an executive summary. Mr. Hanley responded that it was similar to an executive summary in that it would help communicate ATSDR’s findings.
Facilitator: Bob Craig, ORRHES
Bob Craig stated that James Lewis had left the meeting, but that Mr. Lewis had prepared a letter regarding an issue that was discussed at the last meeting. Dr. Craig summarized that at the last meeting, he had mentioned that it had come to his and ATSDR’s attention that DOE-Oak Ridge Operations (DOE-ORO) was considering withdrawing its liaison, Tim Joseph. Dr. Craig continued that DOE did not see the value of providing Dr. Joseph’s assistance to the committee. Dr. Craig said that he had personally made strong objections to the manager of DOE-ORO, who seemed to be receptive, but was not very familiar with the issue. Dr. Craig recalled that when this process was initiated, Leah Dever of DOE was very strong in her opinion that the committee received the full support of DOE. As Mr. Lewis had left, Dr. Craig explained that Mr. Lewis had prepared a letter that he was recommending that ORRHES write to DOE. Dr. Craig paraphrased the letter for the PHAWG:
It has come to the attention of ORRHES that DOE may be considering not providing a liaison to ORRHES. Dr. Tim Joseph is a tremendous asset to the ORRHES. His professionalism and candid response to questions and requests for information have greatly improved the efficiency of the subcommittee’s deliberations, the quality of information provided to the public, and the community satisfaction with the ORRHES/ATSDR process. Dr. Joseph represents the DOE extremely well and provides an invaluable service to the Oak Ridge community. We request that you maintain this liaison.
Al Brooks explained that he was on the Oak Ridge Environmental Justice Committee (OREJC). The committee does not attempt to duplicate other efforts, but instead tries to look at things that they can possibly supplement. He stated that OREJC had addressed this question about two or three months ago because Tim Joseph also served as a liaison to this group. According to Dr. Brooks, Dr. Joseph’s participation on OREJC had not yet been called into question. Dr. Brooks noted that, in addition to having all of the necessary attributes, Dr. Joseph was also the last corporate memory that DOE had for many things that this organization depended upon. Dr. Brooks said that he objected to Dr. Joseph being taken off of ORRHES. However, Dr. Brooks had already written two letters and thought that it would be better not to submit a third letter. Bob Craig offered to write the letter. Charles Washington made a motion to have ORRHES write the letter on behalf of OREJC. The motion passed unanimously.
Charles Washington thought that DOE may be trying to remove the liaison because at one time, it was voted that a DOE liaison should not sit at the table. Bob Craig replied that he still believed that this should be an ATSDR independent citizens effort and that DOE can provide information, but that he did not think that DOE should be a voting member. Mr. Washington thought that DOE should sit at the table. Al Brooks agreed and said that he believed that Tim Joseph had overcome any handicap that he may have had from sitting in the audience because he was extremely helpful to the committee and to ATSDR. The meeting was adjourned at 7:45 pm.