ORRHES Meeting Minutes
June 8, 2004
- Call to Order/ Opening Remarks
- Introduction of Subcommittee Members
- Agenda Review, Correspondence, and Announcements
- Status of Action items
- Presentations and Discussion
- Public Comment
- Additional Presentation and Discussion
- Work Group Reports/Discussion/Recommendations
- Public Comment
- Project Management Status Update
- Unfinished Business/New Business/Issues/Concerns
The Oak Ridge Reservation Health Effects Subcommittee (ORRHES) convened on June 8, 2004 at the DOE Information Center at 475 Oak Ridge Turnpike, Oak Ridge, Tennessee. Chairperson Kowetha Davidson called the meeting to order at 12:20 PM, welcoming all attendees with special notice given to the EPA and ORIA members from Washington, D.C. who were present. No other opening remarks.
Kowetha Davidson asked all attendees to introduce themselves. The attendees present during the meeting were:
Kowetha Davidson, Chairperson, ORRHES
Charles Yard, TDEC (standing in for C. Nwangwa)
Brenda Vowell, ORRHES member
Pete Malmquist, ORRHES member
LC Manley, ORRHES member
Bob Craig, ORRHES member
David Johnson, ORRHES member
George Gartseff, ORRHES member
Marilyn Horton, DFO, ATSDR
Charles Washington, ORRHES member
Barbara Sonnenburg, ORRHES member
Tony Malinauskas, ORRHES member
Karen Galloway, ORRHES member
Susan Kaplan, ORRHES member
James Lewis, ORRHES member
Jon Richards, EPA Region IV
Al Brooks, member of public
Tom Sinks, CDC/ATSDR
Jan Connery, ERG (contractor to ATSDR)
Sandy Issacs, ATSDR
Jerry Pereira, ATSDR
Trent LaCoultry, ATSDR
Loretta Bush, ATSDR
Jennifer Sargentsen, ATSDR
Jack Hanley, ATSDR
Bill Taylor, ATSDR
Lynne Roberson, member of public
Paul Charp, ATSDR
Timothy Joseph, Department of Energy (DOE), Oak Ridge Office
Erika Bailey, Auxier & Associates
Terry Lewis, member of public
Thomas Lewis, member of public
Lowell Ralston, EPA ORIA
Jeff Crane, EPA Region IV
Winston Smith, EPA Region IV
Bonnie Gitlin, EPA ORIA
Don Box, ORRHES member
Peggy Adkins, ORRHES member
Herman Cember, ORRHES member
Kowetha Davidson reviewed highlights and changes to the agenda for the meeting.
- ATSDR/EPA presentation and discussion by Tom Sinks.
- PA/SI information presentation by Jeff Crane.
- EPA ORIA presentation by Bonnie Gitlin.
- EPA ORIA question and answer session with ORRHES members and members of the public.
- James Lewis stressed the importance of allowing plenty of time for EPA ORIA presentations and discussions and asked for flexibility in the agenda. Kowetha Davidson noted that Paul Charp and Tom Sinks had to leave early and their presentations could not be moved any later but would consider the additional time needed.
- The project management update presentation by Jerry Pereira was moved down the agenda, to take place just before unfinished business.
- The remainder of the agenda would be followed as written regarding work group reports, discussions and recommendations.
- Public comment times were fixed and would not be changed.
No correspondence to report since the April 13, 2004 ORRHES meeting.
No additional announcements.
Motion: Approval of April 13, 2004 ORRHES Meeting Minutes
Charles Washington made the motion to approve the minutes of the April 13, 2004 ORRHES meeting. George Gartseff seconded the motion. Before voting, Susan Kaplan requested a correction be made to the second bullet on page 24. The original text stated "ATSDR's mandate to use existing data", with the correction to read "ATSDR's mandate to generate new data." No additional corrections were requested.
The minutes of the April 13, 2004 ORRHES meeting were approved by voice vote with none opposed.
Marilyn Horton graciously thanked all attendees of the ATSDR/EPA meeting held the night before. She then directed the group's attention to the Action Items handout regarding the two motions made during the April 13, 2004 ORRHES meeting.
The first motion, "ORRHES recommends that members of ATSDR/EPA Region IV and ORIA hold a public forum on the evening of June 7 to discuss the outstanding EPA issues. It was also recommended that a court reporter be present to take verbatim minutes of the public meeting." Ms. Horton confirmed this did take place the evening before and that discussion would be continued during the meeting today.
The second motion, "ORRHES recommends that the ATSDR have a community strategy in place prior to the release of the Health Statistics Review results. Also, that the Cancer Incidence Review strategy and data be reviewed by the Ad Hoc committee, the PHAWG and ORRHES prior to its release to the public." Ms. Horton noted that ATSDR is having internal discussions with D. Williamson, DHS and DHEP and are preparing this and will be working with Ad Hoc, PHAWG, and ORRHES prior to its release to the public. This is scheduled to be presented at the next meeting in August.
There were no questions regarding the status of the action items.
Presentation by Tom Sinks:
Dr. Sinks condensed the presentation he made the night before and did not use overheads.
Dr. Sinks began by thanking ORRHES for allowing them (CDC/ATSDR) to be present. He indicated they have finished the public health assessment on uranium releases from Y-12 and summarized their conclusions: the data was adequate for them to make the determination that there were no exposures large enough to the community to have resulted in any health effects.
Dr. Sinks praised all the critical comments they had received and stressed that even if they do not agree with the comments, they want to be challenged. This is part of their process and is how they continue to improve their process. He encouraged ORRHES, EPA and members of the public to continue to send them.
Dr. Sinks pointed out that they take EPA's comments seriously but stated they feel that even if some of them are addressed it would not change their ultimate conclusion.
Dr. Sinks ensured everyone that just because they have finished the PHA does not mean that they will not remain open-minded. He stated they will consider all new information, especially new data (not modeling old data) that would provide more accurate information about the exposures.
Dr. Sinks concluded by mentioning the eight outstanding PHAs ATSDR is working on. He noted it is very important for them to keep moving toward completing these assessments so they will be able to inform the community if there are other priorities for their health.
Susan Kaplan asked Dr. Sinks to qualify how he can stand up and say there were not any health effects (referring to his presentation the evening before) and suggested that he should say there were not a significant number of health effects.
Dr. Sinks responded by reiterating what he thought he said the night before:
"We have evaluated the data on exposure and the information tells us that we do not believe the exposures are significant enough to have caused health effects, that does not mean the people in the community have not experienced health effects, it does not mean that we know for absolute certain that no health effects have occurred from a variety of different exposures, but in terms of looking at the uranium releases and the information we have, we do not believe there was enough uranium release into the environment that would have caused health effects from the data we have. That is different from saying there were no health effects. We are really talking about exposure and what we think the levels were and what we predict would be the expected health effects on the basis of that."
Presentation by Jeff Crane (EPA Region IV):
Attendees were given a handout containing the information Mr. Crane would be presenting. Dr. Sinks accelerated his presentation to allow more time for the following ORIA presentation and discussion. Consult this handout for more detailed information.
The central point he wanted to convey is that in the cleanup process for the Department of Energy (DOE) in Oak Ridge, there will be some follow on activities that will coordinate with the ATSDR public health assessments, which is a currently planned commitment that DOE has under the agreement that the EPA has entered into with them.
Mr. Crane's role as Federal Facility Agreement Project Manager is to coordinate with his team at EPA Region 4 and oversee that cleanup. He mentioned the presence of Jon Richards and Winston Smith, also EPA Region IV representatives.
EPA Region IV gets technical support from the oversight support contract, ORIA, the Athens lab and the Montgomery mixed waste lab, which is a branch of ORIA.
Mr. Crane noted CERCLA is the cleanup process also referred to as Superfund and what is key to recognize is that for federal facilities, DOE is responsible, as the lead agency, for implementing the cleanup. The EPA's role is to enter into agreement to oversee that cleanup, to be assured that the cleanup is effective and timely. That agreement is referred to as a Federal Facility Agreement and the State of Tennessee is also a party to that agreement.
He explained the National Contingency Plan (NCP) as essentially the rules and regulations as to how the cleanup is done. The key element is at the start of the investigation, there is a preliminary assessment or site investigation process designed to go out and collect available information and samples (as appropriate) to be able to write off areas as no potential threat. The next step in the process provides more detail with quantitative assessment activities under the remedial investigation baseline risk assessment, to ultimately select a remedy and implement it. When the remedies are selected, it is required that a protectiveness determination is made that the remedy will protect human health and the ecological receptors or the environment. It specifically spells out in the NCP that the protectiveness determination must assess and characterize the current and potential threats to human health. The focus for the CERCLA cleanup program is current and potential threats. Mr. Crane noted it has been recognized that ATSDR is performing their health assessments as they implement their analyses. Some data will be shared with them and results of ATSDR evaluations will be shared with the CERCLA cleanup program. Specifically the regulations and vision available; health assessments may be used to support response actions and/or identify the need for additional studies. Recognizing the interrelationship of the two, the FFA established a milestone for this preliminary assessment site investigation to occur after ATSDR completes their public health assessments. That will include both the results of the ATSDR PHAs as well as numerous other ongoing area wide monitoring studies and the ongoing investigations under the cleanup program.
Mr. Crane stressed the PA/SI will be a follow on activity after the PHAs are
implemented. He mentioned the Scarboro community has been
evaluated under numerous studies including this first PHA.
The results of their studies are available on the EPA website
). He summarized their findings by saying the EPA did not find any elevated levels of contamination above background or the preliminary remediation goals for screening whether or not contamination is present at a level of concern. However, the data gaps in that study recognized that Scarboro may not be the most representative area of downwind deposition of the Y-12 uranium releases. Mr. Crane stressed the complexity of trying to determine when contamination has been deposited and at what levels. They recognize there may be other areas that would be suitable to collect additional site specific information under the preliminary assessment site investigation. Currently the available information onsite in Y-12 and from the monitoring studies did not suggest there are elevated levels of concern, but they intend to validate that.
The schedule for this activity is to be completed in 2006. It is a FFA enforceable milestone, which does not mean they have a new tone as to how the EPA is working with DOE to achieve cleanup, this concept just means that DOE is obligated under the FFA to seek funding to implement that study. As with all CERCLA response actions and investigations, there is a community relations process. DOE has a community relations plan and as a part of that there has been a formal federal agency advisory committee, also referred to FACA. The site specific advisory board briefs them regularly on decisions, investigations and the results of cleanup activities. As EPA plans investigations or implements cleanup, they provide public availability sessions as appropriate and as requested.
Mr. Crane concluded by stating the EPA understands there is approximately eight total PHAs that will be implemented over the course of 2004-2005 which would fit the timing of the PA/SI that is scheduled under the FFA.
Barbara Sonnenburg asked Mr. Crane if the background level in Oak Ridge is any higher than normal across the country.
Mr. Crane's response was that there have been numerous background studies in the effort to collect background data. The key is to identify areas that are not impacted by any Oak Ridge releases, so with respect to naturally occurring levels of background, he did not know specifically how that varies with Colorado or other geological areas, but the effort to compare levels to background was to compare to areas that are not impacted.
Ms. Sonnenburg followed up by asking if background levels coming into Oak Ridge are already elevated due to coal burning at the Kingston power plant and other nearby power plants. Mr. Crane's response was there is always some potential for anthropogenic contamination or constituents from other sources and try to account for that when looking for a suitable area for a reference location, which is one not impacted by past activity.
Herman Cember objected to the wording used in the PA/SI Schedule slide (the last slide on page 2) of the EPA Region IV handout. He disagreed with the statement "Confirm expected conditions of no current or future health threat." He commented that by using this wording gives the impression of a preconceived idea and suggested they might selectively use those models or those data that support this preconceived notion.
He suggested the wording - to examine the data to determine whether or not there are current or future health threats. Mr. Crane responded by saying Dr. Cember was correct and the EPA's focus is to examine whether or not the releases have occurred and if the contamination is accumulated. The next step is to evaluate the effect. Dr. Cember reiterated the wording should be changed.
Presentation by Bonnie Gitlin (EPA ORIA):
Attendees were given a handout containing the information Ms. Gitlin would be presenting. She began by apologizing for not attending the meeting the evening before due to airplane trouble, but she was glad to be present for this meeting. She explained her title is the Acting Director for the Radiation Protection Division in the Office of Radiation and Indoor Air at EPA's offices in Washington, D.C. They are the headquarters office with responsibility for radiation policy. The structure of EPA consists of a headquarter office with the policy offices and then each of the regional offices independently have the authority to implement most of the activities under those authorities. So ORIA is not a separate entity, but the regions have independent authorities to implement programs. ORIA typically functions in an advisory role to our regional offices on the best way to implement the various statutes in which the EPA operates under.
She mentioned she would also quickly go through her slides to provide additional time for discussion. Consult this handout for more detailed information.
Ms. Gitlin addressed the question of "who is ORIA and how they fit into the picture for Oak Ridge." She said since EPA was created, their office's mission has been to protect people and the environment from harmful and avoidable exposure to radiation. She explained they have six sub-organizations:
- Federal regulations - activities related to waste disposal. Predominately the activities around the waste isolation pilot plant and Yucca mountain
- Radiation information - assists their other organizations in preparing public information materials on radiation.
- Waste management - deals primarily with low activity materials and other naturally occurring contamination.
- Radiation site cleanup - although they do not actually do cleanup, they provide advice to the regional site cleanup managers on different technologies and tools they might use as they approach cleanups under the different authorities, typically Superfund.
- Science and risk assessment - evaluates risk assessment and issues policy and guidance on radiation protection for the entire agency.
- Radiological Emergency Preparedness, Prevention & Response - has the technical capability to respond to events in which the EPA is the lead.
ORIA partners with other offices throughout EPA and with their regional offices on technical issues and on guidance and policy. They coordinate with federal, state and local governments who have radiation protection responsibilities. ORIA is involved in international activities related to standard setting and guidance development.
Ms. Gitlin expressed one area of confusion has seemed to be the difference between Superfund and ATSDR. ORIA adds more complication to that because they have authorities, in addition to the Superfund responsibilities that Region IV is implementing, to have an overall responsibility for radiation protection, which typically comes in under the Clean Air Act, the Atomic Energy Act and the Clean Water Act. ORIA provides the technical basis to address radiation protection issues under those statutes. ORIA develops radiation limits, guidance and policies in all of these areas: drinking water, air emissions, nuclear waste disposal, etc.
Ms. Gitlin commented the important products of their office have to do with federal guidance. The authority for setting federal guidance for radiation protection was transferred from the Atomic Energy Commission to the EPA when it was created. There are basically two sets of responsibilities with federal guidance:
- Recommendations general principles and policies, these are signed by the president and are few are far between
- Technical Reports summaries of the current science and are used to develop regulations and risk assessments
ORIA also has responsibility for environmental radiological surveillance both for environmental measurements and mobile laboratories that assist with cleanups as well as emergency response.
ORIA contributes to national and international reports (NCRP, BEIR, etc.) to stay in touch with all that is going on with radiation protection and to apply those principles under their own statutes to develop guidance and policies for the EPA and the rest of the federal government.
Ms. Gitlin explained ORIA received a fax of the first few pages of ATSDR's initial draft of the Y-12 PHA on January 21, 2003. They called Region IV and confirmed they were planning to review it, and ORIA agreed they would look at it from a technical standpoint and is the reason for their involvement. Ms. Gitlin clarified their comments to the initial draft were late, but when the public comment version did come out they submitted their official comments before the deadline. These comments still apply because they have not changed nor has anything been added to them.
The basis for their comments came from reviewing all the work that had led up to that point. Basically ORIA agreed with some of the recommendations that had been made by others in the past. ORIA reiterated the specific recommendations and said that from their opinion, as EPA, they agree. They agreed with several of the Task 6 team and ORHASP recommendations and she directed all attendees to review this section of the handout. They agreed with ORHASP recommendations to include soil sampling in and around the Oak Ridge Reservation to try to identify all of the areas affected. Mr. Crane's presentation explained how that would proceed (PA/SI). ORHASP also recommended atmospheric dispersion with tracer gases and that supported ORIA's idea of looking beyond the Scarboro area to find out where the uranium from Y-12 had gone. They also intend to address uncertainty and sensitivity analyses, the need to characterize the fate of past uranium releases and to continue looking for additional site specific historical information that could validate the findings up to this point. ORIA's specific comments were related specifically to past exposures. They agree completely that the current and future issues are not issues. The exposures currently in Scarboro are not a problem.
With respect to past exposures, ORIA was concerned that:
- Scarboro was the only community being assessed
- The Level II screening analysis did not provide enough information as they would want to see to be able to make a determination about past exposure
- Screening level analysis was not particularly conservative
- Quantitative uncertainty analysis was not performed
- ATSDR's health evaluation criteria exceed the limits of national and international radiation protection advisory organizations and are not consistent with radiation protection guidelines and risk estimation methods
- Concurrent exposures/ risks to multiple ORR contaminants are not presented
- The fate and transport of majority of uranium airborne releases are unknown
ORIA's recommendations are:
- Look at all city of Oak Ridge communities
- A dose reconstruction be considered
- Multiple exposure scenarios be evaluated with age, gender and location specific values included.
- Quantitative uncertainty analyses is important for transparency
- Lifetime cancer risk estimates and Hazard Indexes for non-cancer effects should be presented
- Concurrent exposures/risks to multiple ORR contaminants should be presented
- Comprehensive fate and transport should be addressed
Ms. Gitlin expressed she believes all of those things can be addressed as everyone moves forward with the site. They continue to work with Region IV to identify the things from this point to address the additional information needs that ORIA thinks may be appropriate when looking at all of Oak Ridge.
Ms. Gitlin indicated it was time for questions. She introduced Lowell Ralston from her staff as one of the principle reviewers/commentors and will assist her in answering questions.
Herman Cember asked how to obtain copies of the EPA's reports. Ms. Gitlin said she would be happy to provide copies to those who needed them. Dr. Cember asked if ORRHES members could be put on a regular mailing list for future guidance reports. Jon Richards indicated these reports are available on the EPA website, but Dr. Cember indicated the trouble with downloading and printing them out.
Dr. Cember had an additional comment that he does not think that soil sampling is enough to know the actual concentration of mercury, uranium, etc. He also wants to know how tightly bound it is, how transferable it is to plants, how fast it leaks into the groundwater, if it becomes airborne and breathed in how fast will it be absorbed into the body and he indicated he does not see this answered in the health assessments. All he sees is the total gross number, but admits if 100% of the gross number were transferred and absorbed and not be harmful that is fine, but it should be addressed. He requested they should mention how tightly bound or mobile all toxicants are (chemical and radiological) in the site evaluations. Ms. Gitlin thanked Dr. Cember for those comments.
LC Manley asked if there was a time schedule for the additional sampling. Jon Richards indicated the milestone completion is scheduled for September 2006 so it would take place sometime prior to that date.
Mr. Manley also asked why they were challenging the FAMU data. Lowell Ralston answered they were not challenging the FAMU data, they were looking to add more information to it. He noted the FAMU/DOE study only looked at the activity in the first two inches of soil in several sections of Scarboro. Other groups such as ORHASP had looked at taking samples at greater depths (e.g. one meter core samples), and by sectioning that sample you can determine where the radioactivity is at depth and if is mobile. It provides an activity concentration and confirms what chemical and physical species are there and what is transferable to plants depending on the depth and when it fell from the sky. It provides a chronology or dating system for that.
Mr. Manley stressed the EPA claimed the FAMU data was not done correctly. Mr. Ralston responded by saying it was just that they did not go deep enough and also some of the measurement techniques (alpha spectrometry and neutron activation analysis) were not complete. The alpha spectrometry analyses that FAMU/DOE study did and the confirmatory sampling by the EPA was not sufficient to be able to look at the isotopic abundances to tell whether or not it was natural or if it had been enriched and had come from Y-12. Also the FAMU study did use neutron activation which is more sensitive in looking at the ratio of uranium-235 and uranium-238, but it does not tell you of about levels of uranium-234, the third isotope.
Mr. Ralston continued by saying EPA took 8 additional samples, 6 of which were soil. Four of those samples were drilled from 0-6 inches and the other two were 0-12 inches in depth, but it still did not answer the question of contamination at depth and also mixed up the activity within that volume. They also did alpha spectrometry, and repeated it is not sensitive enough to be able to discriminate between the isotopes. So all they could conclude was that the absolute quantity of uranium in the soil was within the range of normal background, but they were unable to say if there was any enriched uranium.
LC Manley suggested they go back to their initial report and read it again.
Herman Cember questioned if it is enriched uranium, as a rough rule of thumb, wouldn't the U-234 activity be approximately equal to the U-235 activity? Lowell Ralston answered that when enriching uranium, you enrich the U-235, but also enrich the U-234 to a greater extent. The higher the level of enrichment, the higher the U-234 activity becomes and it becomes dominant when you are almost at 93% enrichment. You can reconstruct what it might be from the neutron analysis from just U-235 and U-238, but it is just a first approximation it is not an exact number.
Charles Washington stated that if it came from Y-12, there are certain things certain people know, that it should have been. If it came out of Y-12 it came out in vapor phase, condensed and then went into the soil. Certain people know the abundance of the isotope that they were working with and they could, perhaps, add some light if these things are not classified, on what they would expect in that community. After condensing and then decaying over time you should still find it. So I think the question should be asked, what depth do you think you should look for it and if it got into the water systems, how far downstream or upstream should you look for it? You are not really looking for that U-238 there, in the building that you are talking about in which it escaped from, you are not really going to find that much. Lowell Ralston commented that Mr. Washington had some very good points, but he would add that since 1986, there has been an air-sampler in Scarboro, and you can look at the data for the air concentrations and see...
Mr. Washington claimed this does not count because that is the time that production was reduced significantly. Mr. Ralston continued by saying you can measure levels of uranium from Y-12 that are enriched, and you can see it in the air samples starting in 1986, the point being that at this point in time from 1986-1995, releases from Y-12 are observable. You would guess that historical releases would be higher. There is data to suggest from both the Florida AMU study and EPA study, there may be enrichment of uranium in the soil at Scarboro, but it is only within 10% or so of the samples and because the techniques were not sensitive enough to be able to make the discriminations well, but the overall concentrations of uranium in soil are within range of background although on the high end.
Mr. Washington followed up by asking what the normal background is for this area as compared to other areas? Jon Richards responded by saying the sampling they have from Scarboro and the Oak Ridge Reservation as a whole, it is toward the upper end of the U.S. averages for uranium, which are well known, and even for the localized TN areas from the geology. Mr. Washington asked how it compared to Colorado. Mr. Richards answered Colorado would be toward the high end of U.S. natural background because of the fact there is more uranium in their rock than our, but what we are seeing is still within that range of not only the U.S. average but also the TN local area.
Herman Cember commented that when he was a student on the health physics fellowship at ORNL in 1949, they learned that on the average, one square mile of soil one foot thick, contains 3 tons of uranium and 9 tons of thorium, and he could calculate how many parts per million or mg/kilo if anyone wished, but those are the amounts for this area.
Peggy Adkins asked if she understood correctly that ORIA was not going to do these things, EPA Region IV was going to do these things and ORIA be collaborating with them and this would not happen until 2006 when we are through with everything? Bonnie Gitlin confirmed ORIA would be collaborating with EPA Region IV and Jon Richards confirmed the deadline for the PA/SI to be completed is September 2006.
Ms. Adkins continued by saying that it seemed in all of these we look for a needle in a haystack, instead of taking a more direct approach. Once again, she would like to promote a more direct approach which would be to map out burial sites, not just the official sites but the secret burial sites that old-timers can describe where things really were buried and may not be on any official map. Identify where canisters were shot in creeks and so fourth, have someone map out the air flow of this valley/ridge area and combine these maps with maps showing the pockets of deaths and illnesses, and actually test sick people for uranium and radioactivity to see if suspicions are correct. Then move from there as to where to test soil and water. Ms. Adkins expressed she feels everyone is going backwards in this. She said we take a guess and we test and that may or may not have to do with the reality of people who believe they are sick because of radiation or the elements dispensed from the plants.
James Lewis asked if Lowell Ralston had a prepared presentation that would give an overview rather than hitting at all of these questions and questioned would that be more beneficial. He also noted that it was unfortunate because a number of the technical people, who were present for the meeting the night before, were absent today. Bonnie Gitlin responded they would be willing to provide written answers to any questions they receive and they would try to help accomplish the agenda for the meeting today. Ms. Gitlin said Mr. Ralston's presentation would provide an additional level of detail to the presentation she had already given, such as additional background material and summaries of the reports they examined as they developed their review. She said Mr. Ralston had a great deal of material and asked if they could narrow it down to certain key areas to be addressed.
Mr. Ralston said the presentation consists of what documents existed, what information exists concerning uranium releases from Y-12, and that has to do with the Oak Ridge health studies, the sampling and analyses performed by DOE, FAMU, the Prichard report which concluded there was enriched uranium contamination above background at Scarboro, and also the follow up EPA study and ATSDR's technical reviewers comments concerning recommendations for activities that happened before the PHA was evoked. It is a very lengthy process; it would take a long time to get through. I do not think it would look to the specific technical questions that were asked by the subcommittee, which is what he thinks is what they want him to do. He said he would make those slides available to everyone and they could read them and later discuss them, but Mr. Ralston did not think it was necessary to go through them at this point. Basically it just summarizes the evidence before their ORIA report and why they made the recommendations they did based on the recommendations that others had made.
Susan Kaplan asked Mr. Ralston if he could make a presentation just on the questions that were submitted. My question was on the 5000 mrem limit and I want to hear your comments on that. We did not get them last night. They (EPA Region IV) deferred to you (ORIA). Also talk about risk calculations on uncertainty; should we recommend that be done, we have recommended that be done at various points but it has not happened. Bonnie Gitlin said they could address any questions that have not been answered.
Kowetha Davidson asked if anyone else had questions related to this matter.
Bob Craig commented that he does not think uranium a meter down is as likely to be a public health effect as in the first top two inches. I think that what we are looking at is qualitative screening level, looking at the data as best we can, as I think ATSDR did, as we approved the data, we saw the peer reviews, we went through it, and they very carefully looked at if the public could have been affected. I think we came to our answer on that. I also agree that Scarboro is probably not in the direct path, we know quite a bit on this ridge and valley and the prevailing winds go straight down Union Valley. Scarboro is the closest inhabited by far, and if not Scarboro, what community are you talking about? There is nothing in Union Valley; there is a huge landfill, Roger's quarry, then Melton Lake and then Jake Butcher's former house. We are talking about health effects, not ecological effects, which means we have to have a receptor and they have to be impacted. I think the answers to your questions probably need to be answered, you need to go through the PA/SI, submit your research grants as we all do, but it is not the question that we were set out to answer.
Lowell Ralston commented that Ms. Gitlin provided summary of their comments and recommendations. The PHA as was the Task 6 screening evaluation it was based on, only provided information on Scarboro. There are no soil samples taken outside of Scarboro and no estimation of health impacts to anyone else in the community. The Oak Ridge health agreement studies did dose reconstruction for mercury releases from Y-12 to the air and East Fork Poplar Creek, as well as PCBs. Radioiodine was released from X-10. Those dose reconstructions did a very careful reconstruction of where the material went. For the mercury and PCBs, besides Scarboro they considered East Fork Poplar Creek farm family and the contaminations in Woodland; so one of our comments and has been the comments of others, was to expand that screening analyses to include other communities besides Scarboro, in an attempt to account for all uranium released from Y-12 into the environment and where it goes. Now it is true that the prevailing wind up and down valley, moves in the direction Bob Craig said in the direction of Wolfe Valley. It is also true there are calms in that data, in the extent of 25% and the winds aloft about the size of Pine Ridge in the direction toward Scarboro and also beyond it. There are also releases from K-25 gaseous diffusion reactor that went toward Oak Ridge that were considered in the Task 6 report but just in passing. We have environmental data dating back to 1959 that actually shows that the region in between the gaseous diffusion plant and Oak Ridge city, which shows some of the higher concentrations of uranium in air. This could all be coming from the gaseous diffusion plant or coming from Y-12, but the fact is the people of Oak Ridge may have been exposed from uranium from both plants at the same time and that is factored into a public health assessment.
Bob Craig mentioned the effluents from K-25 would be studied in a future PHA.
Tony Malinauskas challenged the issue regarding the absence of quantitative uncertainty analyses. Dr. Malinauskas stated his position is that the overall result, that it is safe to live in the Scarboro area, would not change had an uncertainty analysis been done. His reason for that is the number of measurements that had been made of all of the affected parameters are sparse. There are very few replicates made of the samples and to assign an uncertainty on any of the parameters is merely guesswork. He feels guesses are being added to other assumptions and guesses. Dr. Malinauskas thinks the EPA would agree that the assumptions that have been made are largely conservative. He does not think that an uncertainty analysis is a significant efficiency relative to the health effects study. He admits uncertainty analyses can be very useful in allocating a limited amount of money for additional samples to determine what is important. As far as this study is concerned, based on the current data, an uncertainty analysis would not have added anything to the substance.
Lowell Ralston responded by saying we do not really know what the level of exposure was in Scarboro other than the screening analysis that was performed initially by Task 6 and adopted by ATSDR, who did not change any of the parameters that went into it, they just simply changed it to dose and scaled it up to 70 years. So nothing is really changed, nothing has been gained. The people who did that analysis, the Task 6 group, did it as a screening analysis to make a decision if additional information was needed about releases, as well as perhaps, potential exposure. The final value they calculated as a screening index for that assessment, the same on that ATSDR for their PHA, was 8E-5 which is borderline with their decision criteria, the risk criteria of 10-4. The people who actually made the estimates of the releases from Y-12 to the air and water, based a typical adult, recommended a dose reconstruction be performed to provide more detailed analysis. To fill in the missing information, particularly in the release records, to provide some measure of the air terms associated with each one of those releases which can be very high. The Task 6 group went back and looked at the official records from DOE for air releases of uranium and came up with a value that was seven times higher based on unmonitored releases from that facility over the 1944-1995 period. Based on that they concluded there was also gaps in their information that they could not fill and that is a very large part of the uncertainty analysis, as well as what came down East Fork Poplar Creek and who was exposed. So again the analysis focused on the one community of Scarboro, there is a lot of uncertainty in the data that went into the calculations, which was for a typical screen, it was designed only to make a decision on whether further evaluations were important or not. It was not meant to be a health risk assessment. For those reasons and the recommendations of others, we believe that uncertainty would provide a better estimate of what the exposures and health risks might be in Scarboro only because we only have that data set, and the range of those values within a 95% confidence boundary, as was done for the dose reconstruction of mercury and PCBs. We think it is a helpful thing.
Dr. Malinauskas responded that he would agree if Mr. Ralston was talking about additional sampling but using the currently available data and putting and error bound on it is not going to change the data. Mr. Ralston asked him to clarify what data he was referring to. Dr. Malinauskas answered all of the data that are used in the health assessment. Dr. Malinauskas continued by saying that in every case you take a parameter and are going to guess at what the uncertainty is associated with that parameter, cause you do not have a lot of data on which to do a statistical analysis. Mr. Ralston commented that he thinks on parameters such as inhalation rates, we do know what the ranges of those values are. For this particular screening analysis, for inhalation exposures for example, it was assumed that a person spends 9.6 hours of their time a day at the site indoors. The concentration indoors is one-third of the outdoor concentration. For a typical exposure of an individual who actually spends more time at the site, 16.5 hours and 2 hours outdoors results in an increase in their inhalation intake and dose by a factor of 3.5, which is one of our comments we made in our document. This is an example of how the differences and assumptions on exposure scenarios can change the results that you get. Dr. Malinauskas said he stood corrected on the inhalation rates but it is the concentrations that are being inhaled and is my concern. Mr. Ralston said what he is pointing out is they are highly uncertain and that was also said by the people who actually reconstructed them.
Charles Washington commented that we keep drawing out the word uranium but the form of uranium is important from the Y-12 plant, it is not just uranium. He stated he could not say what it was, but knows someone present knows what form the uranium was in if there were emissions from the Y-12 plant.
George Gartseff commented "let's not discourage them (EPA)." He thinks it is very good news that additional sampling is going to be done in an area that was criticized for not having been investigated. Further, there is hard evidence that this process is at work, even though long and frustrating at times. ORRHES has now seen that we had the CERCLA effort with a FFA in place at the Reservation. In a parallel effort ATSDR has done their PHA and now are going back and formally modifying the legal agreement to do further sampling to help close these gaps. Since this is now a FFA action, is DOE going to be the lead agency, to what extent? Also, how will ATSDR and EPA be involved in defining the scope and methodology that will be used? Jon Richards answered DOE is the lead agency and they will be responsible for preparing the sampling analysis strategy that would be conducted. EPS and the State would have an oversight role and we would encourage community participation and planning of that effort. Mr. Richards stressed that he does not want this group to be misguided and misinterpret that the objectives of that assessment are necessarily different than the end results of evaluating these PHA assessments: that data may be important to reveal new information that ATSDR may want to look at. Our (EPA) objective is to find out if there is existing contamination that should not be there and take response actions to go out and clean it up. We have investigated Scarboro, others have investigated Scarboro, and we have not seen contamination that would require cleanup.
Kowetha Davidson asked Jack Hanley if he would like to respond to the discussion. Mr. Hanley said he would like to clarify something Lowell Ralston had mentioned. Mr. Hanley stated the Task 6 authors made some suggestions at the end after looking at the uncertainties, and they say, at the end of the document, that for a comprehensive dose reconstruction we would suggest these recommendations. Also, our technical reviewers came out with suggestions if further non-conservative assessment was needed, then these are things you may consider, but our technical reviewers said the Task 6 was appropriate to make public health decisions. They did make recommendations and they were critical because we paid them to be, to find the limitations of the Task 6 so that ATSDR can use the data and the document within those limitations. We presented this material to the subcommittee and the work group and discussed many of these issues at the Subcommittee and PHAWG meetings, but the key is the Task 6 made suggestions if someone was going to follow up and do further non-conservative dose reconstruction.
Lowell Ralston responded yes it was true that they made these recommendations and they also concluded that "since the level 2 assessment (that is the screening analysis formed by Task 6, which is what ATSDR used for the PHA) is just below the criteria with the most conservative assumptions removed regarding the source term and exposure parameters, potential exposures to uranium releases could have been of significance from a health standpoint and should be considered for dose reconstruction." This came directly from the Task 6 report. On the basis of this conclusion they made their recommendations. Also, the steering panel after seeing the results from Task 6, stated "the results of the refined uranium screening analyses found cancer screening indices slightly below the panel's decision guide for carcinogens. The phase 2 uranium screening results are uncertain for a number of reasons: 1) appropriate air and soil monitoring data for the years of highest releases are absent, 2) there are large uncertainties associated with the atmospheric dispersion and transport mechanisms of airborne uranium, 3) information concerning the amounts of uranium released during the past years is very incomplete, because of these uncertainties the panel made several recommendations." Which these are the ones Bonnie Gitlin showed in her presentation.
Herman Cember responded to earlier comments from Peggy Adkins by saying Hanford has uranium and transuranic registries, where they have autopsy data and careful analyses on residents, workers, and so on. Dr. Cember presumes that the things people were exposed to there is the same, to a first approximation, as what the people here were exposed to. He suggests it might be informative to look at the analyses and to have it all published and again it is available from the uranium and transuranic registries with Washington State University (if he recalls correctly).
Herman Cember then addressed Lowell Ralston saying you did mention the K-25 gaseous diffusion plant and the gas diffused is uranium hexafluoride, and I do not know in what form the uranium is emitted but when the uranium gets outs with moisture it is hydrolyzed and Dr. Cember thinks you get about 4 moles of hydrogen fluoride for every mole of hydrogen hexafluoride. Dr. Cember stated the HF, mole for mole, is very much more toxic than is uranium although the effects are different and short lasting, but he wanted to know if we there data on that and whether it might have affected people who asthma or COPD. Also, did we monitor for fluorides? Mr. Ralston answered he does not know.
Al Brooks made comments about 1984, the year of George Orwell's rather famous book and the year in which the first samples were taken on this project and the greater residential Oak Ridge areas. We have been at it 20 years, and without repeating all the arguments, he would just like to know when it is all going to end. Every time we raise these questions, the neighborhoods they are raised about take a beating. Poor Scarboro has taken a beating over and over and this will extend to any other neighborhoods. Mr. Brooks then went on to comment on some of the sampling situations. Some people say no samples were taken around the Oak Ridge Reservation and that is not true. Several miles east and west of the Oak Ridge Reservation were a part of the background survey. These samples did not show any excess uranium. However, you make the argument that the stuff that came over the hill, did not affect only Scarboro, it went further. If you will look at the map for uranium from Y-12 to contaminate all the residential areas of Oak Ridge, it would have had to travel some distance, but no one ever mentions the fact the air occasionally flowed to the south but it did. If uranium was coming from Y-12 it would have contaminated those areas but those are some of the areas sampled in the background survey and they do not show levels of elevated uranium. Mr. Brooks also mentioned the fly-over data saying this is an example of negative data but no one likes to site negative data. When you are truing to prove something did not happen, negative data is what you have got. The fly-over data shows vast areas of the Oak Ridge Reservation and the Oak Ridge residential area to be at background levels. Then you say it is not sensitive enough. Down at the far end of East Fork Ridge, there is a natural outcropping of Chattanooga shale, which a uranium bearing strata. Mr. Brooks believes it shows up as a three contour spot, but it does show uranium. Furthermore down along the Clinch River, four cesium spots show up and these have been surveyed in a walkover by TDEC and were found to be at half or less of any action level. He stresses the fly-overs are picking up any significant deposit. Every one of those fly-overs, when they get a new one contour interval, they do a ground walkover to establish if it is accurate. So you have several surveys taken over the years, which show in general, the Oak Ridge residential areas and vast areas of the Reservation are indeed not contaminated and yet no one ever wants to refer to these. Mr. Brooks asks why do we not look at the data we have? He urges to be very careful to have some reasonable objective in mind to accomplish some reasonable purpose that is necessary to public health before you subject this whole community to the inspection process and the negative comments the news media will make while doing this.
Herman Cember said he supports the comments from Al Brooks. Dr. Cember also mentioned he was in Oak Ridge in 1949-1950 and he knows for a fact there was a monitoring station at what used to be ORINS, the Oak Ridge Institute of Nuclear Studies. He did not recall exact numbers but knew the levels were always well below the limits for residential areas. They did regularly sample the area around Jackson Square. Lowell Ralston said he could not agree with them more, that we should look at the historical environmental data. There have been monitoring stations all around the Oak Ridge Reservation dating back to 1959. He remarked EPA has in its possession, public health service records dating back to 1959 and EPA records dating back to 1971. These were contractor reports submitted, on the concentrations measured in air, soil and other media in and around the Oak Ridge Reservation. If fact the EPA has gone through some of these records, they would be helpful in recreating what the air concentrations might have been. Mr. Ralston mentioned he has slides with this information but essentially we found, with respect to soil sampling for 1971, data which show the concentrations in soil they are measuring near some of these air monitoring stations show contamination levels higher in areas other than Scarboro. These areas include the East Fork Popular Creek farm area. Mr. Ralston circulated a slide with this information.
Mr. Brooks remarked that he does not find it surprising that certain spots in Oak Ridge show high uranium. Chattanooga shale existed here; it covered the whole area and was eroded away. At the Kentucky border, the shale goes up to 64 parts per million. Mr. Brooks also mentioned he was told by a very reputable person that in middle and west Tennessee there is 350 million metric tons of uranium in the shales.
Lowell Ralston remarked it is EPA's belief that the fly-over gamma spectrometry surveys are not sensitive enough to pick up depleted or enriched uranium. We are talking U-238, U-234 and U-235 without any of the decay products present. Uranium can be measured with fly-overs but it does not cue in on the uranium isotopes. It cues in on radium-226 and the following isotopes that have higher gamma abundance and are in secular equilibrium with their parents, so there is really no measurement of uranium, it is inferred from their decay products. Mr. Ralston explained when we say the fly-overs are not sensitive enough to pick up depleted or enriched uranium, that is, minus their decay products. We believe that to be a very true statement.
Al Brooks responded the fly-overs pick up uranium at K-25 and also at Y-12. Incidentally every one makes the assumption that Y-12 produced U-235 and that is wrong. They made penetrating shells, casings for nuclear weapons and they were made out of depleted U-238. Y-12 has processed more U-238 than U-235. Every time you say Y-12 put out U-235, you have to know when you were talking about it, which buildings you were talking about and which manner it was emitted. It is not safe to assume that Y-12 was generating nothing but U-235 over its history. Mr. Ralston agreed that Y-12 handled depleted uranium as well as enriched uranium for many different reasons at many different times, but as with anything it is a matter of quantity.
Kowetha Davidson referred to when Mr. Ralston was talking about uncertainty analysis and their screening analysis, and mentioned they were borderline at 10-4. Dr. Davidson asked Mr. Ralston if he thinks this is an action level for public health? Dr. Davidson clarified she was not talking about cleanup, which is what EPA does, but should this be the decision level that ATSDR uses for cleanup if they should set their policy at 10-4. Are you saying ATSDR should adopt this same value used by EPA, stating there is a public health problem at 10-4? Mr. Ralston responded the EPA is not telling ATSDR what they should or should not use. They are telling us they used their evaluation criteria of 100 mrem/year for non-cancer radiogenic effects and the 5000 mrem in 70 years. We are saying the EPA finds acceptable risks within the range of 10-4 - 10-6, when setting their regulations for cleanup or other things, but generally it is an acceptable level of risk. For this specific application, which is a health risk assessment of Scarboro or all of the Oak Ridge communities, what we would recommend would be a dose reconstruction of a similar nature that was performed for radioiodide, mercury and the PCBs, which presented a central estimate of cancer risk with 95% uncertainty bounds, and to compare those risk levels among themselves and let people decide whether it was a significant risk.
Kowetha Davidson explained 10-4 is an EPA level for health risk assessment, but what we are doing is a public health assessment which is a little different. You use that for your analysis as though you are saying because you did not use 10-4 then there may be a problem here. Mr. Ralston remarked he must not have clarified himself. He replied when I mentioned Task 6 and it was slightly below the screening criteria, 10-4 caner risk was chosen by the oversight panel for the Oak Ridge health studies as their point of decision making as to whether or not a contaminant or release pathway deserved further evaluation. Mr. Ralston continued, when saying they did a level 2 screen, which is for a typically exposed adult, the value they calculated, which is the value ATSDR used for their public health evaluation, they just changed it to dose and multiplied by 70/52 years, was just below their risk criteria of 10-4. The value was 8E-5 and because it was so close they did not know whether or not they should make a decision to put uranium off to the side and deal with something else or recommend it for further evaluation. They used that risk level themselves, we did not provide it to them, it just happens to be the same level we use for making decisions. Mr. Ralston clarified he was not saying that ATSDR should use 10-4.
James Lewis mentioned Dr. Sinks indicated that the health assessment will stand if there is no new data found and if there is any new modeling, nothing would change in the health assessment. Mr. Lewis' question is to EPA; is there any new data or something you have that relates to data that may not have been considered or was a part of ATSDR's evaluation? Dr. Sinks clarified they would be open to any data, be it remodeling of existing data or new data. Dr. Sinks said what he keeps hearing and actually saw in one of Bonnie Gitlin's slides, is that every one has been calling for new data that would improve these models, and he said ATSDR concurs. He also thinks EPA concurs. Dr. Sinks continued by saying he is an epidemiologist, not a health physicist or a modeler per say, but he likes to see data that helps us anchor the models and validate them and thinks that would be useful in this situation. Lowell Ralston responded he agrees with that and by new information, ATSDR had all the information available to the Task 6 report team, plus the additional information from the FAMU sampling effort and the Prichard report, plus EPA's confirmatory sampling analysis. Mr. Ralston commented what he just showed, by way of some of the environmental data that exists, is something that Task 6 and others pointed to as a way of confirming the models they used in their analysis looking at that historical data set. What we (EPA) are saying is that we have access to some of that data. We believe that DOE, or AEC before them, might have these records for the environmental data that would help to inform us if the screening that was done was adequate with respect to measured concentrations in air, water and soil to confirm or not, the estimates that were made about what those concentrations might be in some of those areas. Also, to look at those areas, perhaps, for additional soil sampling to look for that missing uranium.
Herman Cember commented on the values of 10-4 and 0.8E-5. He explained the 10-4 value was derived by the International Commission on Radiological Protection (ICRP) many years ago. ICRP wanted to see where they should start looking at safety standards and they found that generally speaking people accepted a risk of eminent loss of life or a limb, at around one chance in 10,000. This was done by looking at real things such as skiing accidents, automobile accidents, boating accidents, etc. The committee could have decided any value but they decided lets have an average risk of eminent loss of life or limb at 10-4. This is how that came about and in the case of radiation, it is not that we just observe these deaths but these are calculated numbers. They thought a calculated number like this would be a good safety factor for setting prospective safety standards, not for looking back and counting dead bodies. The 10-4 is an arbitrary number that has a reasonable basis in fact, but it was determined by a committee who could have determined anything else. Dr. Cember said to think that 0.8E-5 and 10-4 is different is ludicrous. Lowell Ralston responded he agreed and Dr. Cember is right about the basis although he has heard other stories. Mr. Ralston said basically there is nothing magical about 10-4, even EPA does not make decisions at exactly 1E-4, they look at about 10-4 and will even consider risks up to 3E-4 because there is uncertainty in all of these analyses. He clarified what he said before was the oversight panel for the Oak Ridge health studies shows 1E-4 as their decision point as whether or not to look at something in our evaluation. Yes it is true that you cannot distinguish between 8E-5 (or 0.8E-4) and 1E-4. Mr. Ralston explained they were at a point of saying well we do not know if this is significant or not, it is just barely at but not tripping over our 1E-4 and it was just a decision point. Dr. Cember is right, EPA does not hold fast to 1E-4, there is nothing magical about that.
Susan Kaplan stated she would like to ORIA to comment on the 5000 mrem screening limit and apologized if they have done this already. She asked ORIA to talk about it in terms of the impact on Oak Ridge. Ms. Kaplan mentioned she has heard comments that people are fearful of reopening rods and apologized if she misunderstands that. She also asked is there any impact from a national standpoint and has the 5000 mrem screening limit been used in other cities or is this the first time. Lowell Ralston commented there is actually three issues. The answer to Ms. Kaplan's last question is that we have never seen these limits before, and I say these limits because there is the 5000 mrem over a lifetime limit that they set for radiation cancer effects and the 100 mrem per year for radiogenic non-cancer effect level. The cancer policy they have, they do not look at cancer risks for radionuclides, which are carcinogens and are treated differently than the way they have policies for chemical carcinogens in the way they evaluate health risks/cancer risks. Mr. Ralston continued, reading from his notes, "the 100 mrem per year for radiation induced non-cancer effects is not applicable for chronic low dose exposures that are experienced from releases to Y-12, essentially it is looking for acute radiation effects that do not occur until several orders of magnitude higher than 100 mrem in a year." What we said was that we just do not see its applicability here and it should not be used for this screening purpose under those circumstances. The 500 mrem over a 70 year lifetime, as they define it, is an AdHoc value that was made up by ATSDR, and it represents their judgment about observable or statistically significant cancer risks based on epidemiologic studies. The studies are well known to have a detection problem with very small populations of individuals and that is why you need very large populations to be able to see these cancer risks from radiation. Mr. Ralston explained that if you were to translate their 5000 mrem lifetime dose it corresponds to roughly 4E-3 lifetime cancer risk, or 4 chances in 1000, which is about 10 times higher than our 3E-4 interpretation of EPA's upper bound and about 40 times higher than the decision criteria used by the steering panel of 10-4. If you compare it to 10-6, which is the absolute lower limit of what we have for acceptable risk, it is over 4000 times higher. Mr. Ralston added the separation between observable cancers from radiation exposure and where EPA tends to make decisions on acceptable cancer risk is an order of magnitude of 10, which means their observable level is has no margin of safety. You have to have clinically diagnosable cancers before any action would take place and that does not seem to make sense to EPA, when the level that we look at is acceptable as only a factor of 10 lower. Mr. Ralston remarked, this is a question, this is the first time we have seen these values and the first time we have seen them applied under these circumstances. He stated they are not the values we would choose and we find this somewhat troubling.
Kowetha Davidson asked Paul Charp to respond to this with ATSDR's perspective. Mr. Charp needed a moment to prepare so she allowed other questions.
George Gartseff replied that he was starting to get confused. He asked everyone to please put risk in laymen's language. He asked are we talking about absolute risk, like 4 out of 10,000 people will get cancer; are we talking about incremental or excess risks over normal expected cancer cases. Mr. Gartseff asked for Mr. Ralston to please clarify that and continue to keep this is mind during the conversation. Mr. Ralston responded when we talk about cancer risks, we are talking about excess cancers above all other cancers and all other causes of death. This is the incremental increase due to your exposure, in and above, all of the other background exposure that is there.
George Gartseff asked is this the number of cases that you expect to see or the chance that you might see one additional case. Mr. Ralston answered in a population of one thousand people, we would expect that four of the cancers that occur in that population would be due to that exposure.
Herman Cember explained that most of the cancer risk numbers that are available come from the lifetime studies of survivors of the Japanese bombings. He believes the total number of excess cancers in all the survivors, to date is around 500 (a little less). Although there is a positive correlation and a good dose response effect for total number of cancers (and even for several of the individual cancers such as breast cancer, etc.) there is not a statistically significant relationship between the cancer incidence and the dose. RERF does the best they can with the data they have and come out with a risk factor, but I think for many of the cancers, there is not a statistically significant relationship between cancer incidence and dose and therefore we really cannot get a reliable number for that excess chance of getting cancer. The number of cancers on which all of this is based is around 500, so there is a lot of uncertainty in all of this. Lowell Ralston said Dr. Cember is correct, that is about the number of cases. Mr. Ralston added there 100,000+ people in the lifespan cohort study. It is the largest group of individuals we have to look at the epidemiological effects, which require very large populations to see these effects. Mr. Ralston explained he disagreed though. He said we do see statistical cancers at these levels in the lung, bone, etc. He said at ATSDR's level of 5000 mrem in a lifetime effective dose, which translates to a lung dose of about 42 rem. We do see statistical cancers to the lung at 42 rem from the A-bomb survivors. Mr. Ralston mentioned he had a sheet showing what the statistical relationships are between the cancers.
Kowetha Davidson announced it was now time for public comments.
Al Brooks asked if the committee was through with the extension of last night's activities. Kowetha Davidson answered no, it would be continuing. Mr. Brooks added that he wanted to make a few additional comments before it was finished.
No additional comments.