Oak Ridge Reservation: Exposure Evaluation Work Group

PExposure Evaluation Work Group

February 14, 2005 - Meeting Minutes

Attendance

ORRHES Members attending:
Tony Malinauskas (Chair), Bob Craig, Kowetha Davidson, David Johnson, and James Lewis

Public Members attending:
Judy Fussell, Lynne Roberson (phone), and Danny Sanders

ATSDR Staff attending:
Loretta Bush (phone), Mark Evans, Jack Hanley (phone), Marilyn Palmer (phone), and Bill Taylor

TA Consulting, Inc. (contractor):
Amy Adkins

ERG Contractors attending:
Liz Bertelsen (phone)

Purpose

Tony Malinauskas called the meeting to order at 5:30 p.m. The purpose of the meeting was for Mark Evans with the Agency for Toxic Substances and Disease Registry (ATSDR) to present information pertaining to the K-25 Public Health Assessment (PHA).

Tony Malinauskas asked for comments on the meeting minutes from January 10, 2005. No comments were noted and the minutes were approved.

Oak Ridge Reservation—Former K-25 and S-50 Sites Air Releases PHA

Presenter: Mark Evans, ATSDR

Mark Evans explained that comments received on the data validation draft (DVD) PHA are currently being addressed. Revisions are also being made to prepare the document for its public comment release. Dr. Evans said that this PHA solely evaluates off-site exposures to air releases from the K-25 and S-50 facilities. He stated that other PHAs would be evaluating groundwater and surface water related to these facilities.

Mark Evans noted that the PHA would 1) evaluate off-site (community) exposures to air releases from K-25 and S-50, 2) assess potential future releases from uranium hexafluoride (UF₆) cylinders currently stored at the East Tennessee Technology Park (ETTP), formerly known as K-25, and 3) address unresolved community concerns regarding historic air emissions. Dr. Evans believed that the possibility of future releases from UF₆ cylinders probably posed the largest potential hazard.

Mark Evans stated that the primary processes at the K-25/S-50 site involved gaseous diffusion of UF₆. Consequently, uranium and fluoride are the primary contaminants of concern (COCs) for this PHA. Dr. Evans explained that there were some other contaminants released, but uranium and fluoride represented the most significant releases. He said that the K-25 emissions and doses were evaluated previously in the Reports of the Oak Ridge Dose Reconstruction: Uranium Releases from the Oak Ridge Reservation—a Review of the Quality of Historical Effluent Monitoring Data and a Screening Evaluation of Potential Off-Site Exposures, also known as the Task 6 report. Dr. Evans said that the Task 6 report included a thorough review of facility processes, uranium releases, and exposures for the Union/Lawnville community. Based on this review, estimated uranium doses were not a public health concern for people living in the Union/Lawnville community during the years assessed in the Task 6 report.

Mark Evans explained that the Task 6 report had the following limitations:

• Did not use site-specific meteorological data
• Did not evaluate potential short-term (acute) exposure doses
• Focused on Union/Lawnville community (did not evaluate closest residents in the Sugar Grove area, located over the ridge)
• Did not compare estimated environmental concentrations with available environmental monitoring data
• Revised uranium emission estimates were less conservative (health protective) than earlier U.S. Department of Energy (DOE) estimates

Mark Evans noted two outstanding community concerns related to K-25/S-50 air releases: a) the potential public health hazard from fluoride and hydrogen fluoride (HF) emissions, which was not previously evaluated, and b) the potential exposures for residents of the Happy Valley Labor Camp, circa 1944–1947.

Mark Evans presented a graph that showed the estimated airborne uranium releases from the K-25/S-50 facility. All cumulative release estimates were presented in Curies (Ci). The Task 6 report estimated 16.7 Ci and DOE estimated 18.1 Ci. Dr. Evans explained that DOE had not previously evaluated S-50 emissions; therefore, the Task 6 report's S-50 estimates had to be added to the previous DOE emission estimates. According to Dr. Evans, the peak release years were much higher for the DOE estimates. Consequently, Dr. Evans used the DOE estimates for his analyses to be more "health protective." He did, however, use the Task 6 report's differentiation for isotopes because many DOE estimates did not have all of the distribution of isotopic ratios.

Mark Evans presented a table of the significant historic short-term UF₆ releases from the K-25 facility. He did not believe this represented a complete record, but the table included available data that he thought were representative of the most significant short-term releases from the facility. Dr. Evans said that the largest increase occurred on September 1, 1958, which resulted in 1,184 kilograms (kg) (0.55 Ci) being released from K-1131 because of a ruptured filter in a hydrogen reduction system. This accounted for 0.71% of uranium 235 (U 235). Dr. Evans also noted that midnight negatives occurred on various dates. He said that the largest and most significant release was 907 kg. Dr. Evans believed that most other releases were probably significantly less.

Mark Evans presented a table that showed the different types of ambient environmental monitoring data used to evaluate historical uranium and fluoride releases from K-25/S-50. Sampling occurred at other stations, but he discussed stations that were of interest for this PHA. He said that "a good bit of data" exists for different types of media (i.e., air, soil, and biota). Gross beta (1959–1985) and gross alpha (1966–1985) were both monitored in air at stations HP-33 and HP-35. Dr. Evans said that gross alpha in air was no longer documented after 1985 because DOE started conducting more isotope-specific monitoring at these stations. Uranium isotopes in air have been monitored at perimeter and remote stations from 1975–present, and fluorides in air were monitored at stations F1–F6 from 1971–1985. For soil, gross alpha and uranium isotopes were monitored at HP-33 and HP-35. Gross alpha was monitored from 1971–1975 and uranium isotopes were monitored from 1976–1985. Biota (pine needles/grass) was monitored at stations VS1-VS9 for total uranium and fluorides from 1974–1985.

Mark Evans explained the following table that presented the sources, locations, and time frames of K-25/S-50 emissions evaluated in the K-25 PHA. The radionuclides include uranium (234, 235, and 238), technicium 99, and neptunium 237. Dr. Evans noted that he read a report, which stated that no one lived in the Sugar Grove area before 1960. However, he had seen old topographic maps that depicted houses during this time.

Source	Contaminant	Duration	Exposure Area	Time Frame
K-25	Radionuclides Fluorides HF	Acute/chronic Chronic Acute	Union/Lawnville	1945–85 1963 (maximum release year)
	Radionuclides Fluorides HF	Acute/chronic Chronic Acute	Sugar Grove	1960–85 1963 (maximum release year)
	Radionuclides Fluorides HF	Acute	ETTP Workers	Future only
S-50	Radionuclides Fluorides HF	Acute/chronic Chronic Acute	Happy Valley	1944/45 only
	Radionuclides Fluorides HF	Acute/chronic Chronic Acute	Union/Lawnville	1944/45 only

Mark Evans presented a map to show the areas of potential exposures from K-25/S-50 airborne emissions. He evaluated air dispersion from two sources—S-50 and K-25—and used air dispersion process models. The Clean Air Act Assessment Package-1988 (CAP88-PC), a U.S. Environmental Protection Agency (EPA) model for assessing doses, co-locates sources to enable the use of multiple sources. Dr. Evans said that the model provided more conservative estimates because it uses central emission points to derive doses. He used sampling stations HP-33 and HP-35 because about 15 years of monitoring data existed for these stations.

Mark Evans presented a figure to show predicted (DOE and Task 6 report emission estimates) versus measured gross alpha concentrations at HP-35 for 1966–1983. The predominant downwind direction from K-25 was to the northeast from this station. He explained that the line representing measured gross alpha concentrations at this location showed "hard data." He stated that the line representing predicted concentrations based on the Task 6 report's emission estimates peaked in the 1974 time frame. He said that the figure demonstrated that the predicted concentrations are "very good proxy for concentrations measured at that location." Dr. Evans showed the same figure, except for the HP-33 location. He noted that you cannot "do better than" the predicted versus the measured gross alpha concentrations for this station.

Mark Evans said that these figures give him "very good confidence" that the modeling process can predict concentrations that are showing up in measured data. He believed that he could use this process to assess the time periods in the 1940s for which he has no monitoring data. He said that you are normally "pretty happy" if you have a model that is within an order of magnitude; these correlation coefficients are an order of magnitude of 0.6 or 0.7.

Mark Evans presented the following table with the annual doses at HP-33 and HP-35 for the weather years 1999–2003 (excluding 2002).

Year	HP-35 (mrem/year)	HP-33 (mrem/year)
1999	37	6.7
2000	30	4.0
2001	29	7.4
2003	36	2.4

Mark Evans explained that the CAP88-PC model could not use the values for 2002 because there were problems with missing data values in the 2002 meteorological data set. The average was 33 millirem/year (mrem/year) for HP-35 and 5.1 mrem/year for HP-33. Dr. Evans used the 1999 weather years because they had the largest doses.

Mark Evans presented a graph of the annual averages for measured and predicted fluoride in air at selected stations. Predicted concentrations were calculated using linear regression of measured fluoride concentrations with DOE's annual uranium emissions. Fluoride air concentrations were measured from 1971–1985. The highest predicted concentrations were close to 6.0 parts per billion (ppb) in air in 1944.

Mark Evans presented a table with the maximum potential effects from the September 1, 1958, accidental UF₆ release. Dr. Evans explained that the RASCAL3 model, which was used to estimate the doses and concentrations for this table, is a Nuclear Regulatory Commission (NRC) model designed specifically to assess UF₆ releases. The model assumes worst-case meteorological and release conditions. Thus, Dr. Evans looked at the worst-case accidental conditions based on the maximum potential effects from the September 1, 1958, accidental UF₆ release. Dr. Evans explained that concentrations decrease with distance due to air dispersion (except for the HF concentration at 1.0 kilometer [km], which is higher than at 0.5 km). At 0.5 km, the HF concentration is 1,310 ppb; it is 2,680 ppb at 1.0 km. Dr. Evans said that these amounts would be "dangerous." For Sugar Grove (2.57 km distance), the estimated HF concentration was 156 ppb and the estimated uranium dose was 34 mrem. For Union/Lawnville (4.32 km distance), the estimated HF concentration was 27 ppb and the estimated uranium dose was 12 mrem.

Mark Evans showed the work group a table of the estimated annual radiological doses for maximum release years. Sugar Grove and Union/Lawnville were evaluated for K-25 in 1963; Happy Valley and Union/Lawnville were evaluated for S-50 in 1945. Dr. Evans said that the fluoride annual air concentrations were all below 5 ppb. The highest individual effective dose rate (3 mrem/year) in 1963 was estimated for the Sugar Grove community. In 1945, the highest individual effective dose rate (30 mrem/year) was approximated for the Union/Lawnville community. The Happy Valley community had an estimated individual effective dose rate of 14 mrem/year in 1945. Dr. Evans explained that doses considered worst-case (maximum 1999 year) conditions. He said that a slight possibility existed that these could be higher, but that the doses would be close to these estimations and not significantly higher.

Mark Evans read the table below in its entirety, which presented the public health issues, actions, and findings that would be addressed in the K-25 PHA.

Recommendations/Concern	Action	Finding
Additional records research and data evaluation regarding S-50 plant operations and potential releases.	A re-evaluation of S-50 releases was conducted using multiple years of site-specific meteorological data.	Health-protective dose estimates for S-50 releases are below levels of public health concern.
Review of additional data regarding unmonitored K-25 uranium releases.	Long-term analysis of estimated K-25 releases was compared with measured ambient gross alpha concentrations to assess adequacy of estimated emissions.	Measured gross alpha air concentrations are adequately predicted using estimated emissions and the CAP88-PC air dispersion model. Consequently, unmonitored releases are unlikely to represent significant additional source component.
Refinement of the approach used to evaluate surface water and soil-based exposure concentrations. This refined approach could possibly involve shifting to a source- term-based approach and use of additional measurement data.	Measured radionuclide concentrations compared with estimated concentrations predicted from air dispersion models. Surface water addressed in pending PHA.	Measured soil radionuclide concentrations about ten times less than value used for Task 6 calculations. Soil/ingestion concentrations in this PHA are based on CAP88-PC deposition velocity (0.18 centimeter/second), which is the rate that particles are deposited from air onto soil (assumption in model).
Improved atmospheric modeling for K-25/S-50 by using wind data from multiple stations and years. Evaluation of the uncertainty associated with the air concentrations would provide upper and lower bounds of confidence in the estimates.	Improved atmospheric modeling conducted using site-specific stations and multiple years.	Doses/concentrations varied by about 20% over a 5-year period. Estimated doses were predicted using worst-case meteorological conditions.
Improvement of the exposure assessment to include region-specific consumption habits and lifestyles, identification of likely exposure scenarios instead of hypothetical upper bound and typical assessments, and inclusion of uncertainty analysis to provide statistical bounds for the evaluations of risk.	Worst-case exposure factors used in estimating exposure doses at specific locations. Rural default consumption/exposure factors are health-protective.	Predicted, health-protective doses are below levels of public health concern. Consequently, there is no public health basis for further, probability-based analyses.
Refinement of the chemical toxicity evaluation, possibly to include other approaches/models and an uncertainty analysis.	Potential exposures/doses to uranium and fluoride/HF evaluated with respect to chemical toxicity.	Estimated doses/concentrations are below levels of public health concern. There is no public health basis for further, probability-based analyses.
The potential public health hazard posed by K-25/S-50 fluoride and HF emissions.	Health-protective fluoride/HF concentrations estimated for areas of potential off-site exposure.	Health-protective estimates of fluoride/HF concentrations are below levels of public health concern.
Assessment of potential exposures from K-25 and S-50 emissions for the residents of the Happy Valley Labor Camp (circa 1944–1947).	Potential doses to residents of Happy Valley estimated for S-50 releases. There were no significant releases from K-25 while people lived in Happy Valley.	Health-protective estimates of radiological and fluoride/HF doses or concentrations are below levels of public health concern.

Mark Evans said that the current draft form of the document concludes that the cylinders represent a potential hazard of "low likelihood, high consequence." He added that the potential for short-term doses to HF were deemed an indeterminate public health hazard for the Sugar Grove area and possibly for the Union/Lawnville area. Dr. Evans believes that he "grossly overestimated concentrations" because he ignored the ridge altogether. He said that the model indicated that the values might "be in the range that could cause temporary respiratory distress." Dr. Evans does not believe, however, that the concentrations were high enough for any long-term adverse health effects to occur.

Discussion

Danny Sanders asked about the distance between the K-25 site and the Sugar Grove community. Mark Evans said that the community was about 1 to 1.5 miles from the facility. Mr. Sanders asked about this being the closest community to K-25. Dr. Evans said that with the exception of Happy Valley, Sugar Grove would be the closest community to K-25.

Bob Craig noted that there was also a community called Christmas Valley that existed for about 18 or 20 months. Danny Sanders said that there were about three or four different labor camps in existence at that time. Mark Evans asked for the location and direction of Christmas Valley. Dr. Craig indicated the location on a map, and Dr. Evans said that this would have been included in the assessment of Happy Valley. Dr. Evans took the closest points to the potential exposure areas (i.e., Sugar Grove, Happy Valley, and Union/Lawnville) so that he could obtain the most conservative estimates.

Bob Craig believed that there was a rationale for decreasing the isotopes in the Task 6 report, but he agreed with the approach taken by Mark Evans.

Tony Malinauskas asked if K-25 was built in the 1940s. Danny Sanders said that the construction of K-25 began in 1942, and residents lived in Happy Valley beginning in 1943. Dr. Malinauskas asked when processing began at the facility. Mark Evans said that processing began at the S-50 plant in 1944 and at about the same time at K-25. However, Dr. Evans said that no significant releases occurred at K-25 until about 1950 based on emissions estimates.

Bob Craig asked about the processes at K-25 during this time period. Mark Evans said that thermal diffusion processes were occurring, which used uranium. He went through the records to see if any significant accidental releases occurred, but records were incomplete. Dr. Evans was relying on K-25 accidental releases as more significant than S-50 accidental releases. He added that the S-50 facility only operated from 1944 to 1945, for a period of about 11 months.

Bob Craig asked if wind direction was predicted. Mark Evans replied that he used 3-year and 5-year averages. He explained that "slight differences" showed up because one station was down next to the river and in the valley and the other station was higher up. Therefore, he used different data sets for different sources.

James Lewis asked if data were available from monitoring stations prior to the 1960s to 1985 time frame. Mark Evans said that monitoring data were "sketchy" before this time period. He noted that no consistency existed with earlier data, and therefore, he was unable to look at those earlier data in a synoptic manner.

James Lewis asked at what point Mark Evans began to have air sampling data from these stations. Dr. Evans said that he has beta data beginning in 1961 and alpha data beginning in 1966. Mr. Lewis asked if modeling data were used prior to these dates. Dr. Evans explained that he tried to use emissions data and modeling data during periods where he had monitoring data. He said that if he can reach "good agreement" between the monitoring data and emissions data for that period, then this would provide him with a "sense of reliability" that it is appropriate to use these (emissions and modeling) data when he does not have actual monitoring data.

James Lewis asked Mark Evans how comfortable he was with the period of time when he has no monitoring data. Mr. Lewis also asked how confident Dr. Evans was with the monitoring stations placed in the key locations from the 1960s in comparison to what they have now. He noted that they have a lot of data now that people trust.

Judy Fussell asked how they account for not having precautionary measures (e.g., filtering). Mark Evans said that if a contaminant is captured at the source, then it would not be emitted. Bob Craig indicated that a lot of releases occurred prior to 1964. Dr. Evans said that increases in protection occurred after this point in time. Ms. Fussell stated that there had been a rush to accomplish tasks at these facilities in the past.

James Lewis said that one of the purposes of these presentations is to discuss any data gaps that exist. Mr. Lewis noted that data become stronger as they date closer to the present, but that different levels of data gaps exist as they go back in time. Bob Craig explained that they are discussing emissions data as opposed to sampling data. Dr. Craig said that sampling data were missing prior to 1960, but not emissions data. He said that because enriched uranium is extremely expensive, the facility was watched carefully to ensure that it was functioning at an optimum level and thorough records were kept from the 1940s onward.

Danny Sanders asked when the soil data were collected. Mark Evans said that most of the data were collected as part of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, also known as Superfund), which includes data in the 1980s and 1990s.

James Lewis wanted to ensure that they understood the approach that Mark Evans was taking in the PHA. He said that if weaknesses exist, then they needed to be expressed. He stated that emissions data were never clearly depicted. To respond to Mr. Lewis, Dr. Evans presented a figure of contours of aerial gamma survey and uranium soil sample concentrations obtained via flyover data. Dr. Evans said that based on gamma, some contours existed (i.e., along White Oak Creek, East Fork Poplar Creek, and some disposal areas). Dr. Evans said that other than these examples, all of the levels were mainly background based on the gamma surveys. He added that the figure showed a "line of evidence" that minimal amounts of contaminants detected on site in elevated readings traveled off site.

James Lewis asked Mark Evans to elaborate on following the plumes. Dr. Evans explained that he was looking at acute releases and trying to find specific data to match up to the dates and times of those accidental releases. He would define the worst-case conditions for short-term releases and assess the atmospheric conditions that produce the highest off-site dispersion and concentrations. He said that all of the acute analyses are based on worst-case conditions.

Judy Fussell did not understand how improved air emissions would be factored into the assessment. Mark Evans replied that he was not concerned about filtration because he was assuming that if a contaminant was listed as emitted, then it was in the atmosphere and was already released. Ms. Fussell questioned whether Dr. Evans evaluated quantity. Dr. Evans said that he considers quantity, but that this is post-filtration; he was not concerned about anything that was retained—only the quantities that were released. Dr. Evans assumed that 100% was released.

Judy Fussell asked how Mark Evans could take data from the 1960s and use it for 1944. Kowetha Davidson responded. She explained that Dr. Evans was validating the modeling he would be using for times when he has the most data. Once he validates the model for times when he has the most data, then he will use the same model for dates when he has no data to determine exposures.

James Lewis asked about the technology during the time periods evaluated for HP-33 and HP-35. Mark Evans said that the gross alpha technology was "pretty good." Dr. Evans noted that these are annual averages, and that for the technology at the time, these were good at detecting background and elevations.

Danny Sanders asked when fluoride was first used in the diffusion process. Mark Evans said that fluoride was used since the beginning. Mr. Sanders had understood that Happy Valley was closed in 1948 because of the dangers related to fluoride; Dr. Evans said that this could have occurred.

Tony Malinauskas asked if the fluoride counted HF. Mark Evans replied that the monitoring process picked up both.

Bob Craig explained that UF₆ is released, enters the air with water in it, and immediately becomes HF. Dr. Craig said that this was a tremendously powerful acid that would rot a person's lungs and could cause death. Kowetha Davidson said that it would be an acute problem because people would know right away if they were exposed, as it is an irritant.

Tony Malinauskas questioned why the HF concentration increases from 0.5 to 1.0 km. Mark Evans explained that the initial release assumes UF₆, but that there is a transformation process. HF is produced as UF₆ is consumed. Dr. Evans continued that there are differences in transport because UF₆ is a heavy gas, and it sticks to the ground. He said that HF goes up into the atmosphere and disperses. Dr. Evans said that this was all factored into the conservative model, which has undergone a great deal of testing and validation. He stated that the model assumes worst-case atmospheric conditions, including stable atmosphere and low-wind speed. Dr. Malinauskas asked about the wind direction used; Dr. Evans said that the model assumes any wind direction.

Bob Craig believed that humidity was a major contributing factor. Mark Evans said that Dr. Craig was correct, and that humidity was factored into the RASCAL3 model. In addition, he said that the model ignores the ridge between K-25 and Sugar Grove.

Bob Craig asked if the concentrations for Sugar Grove were based on the accident. Mark Evans said that this could have caused some temporary problems (i.e., irritation). He has overestimated the doses, however, and personally believes that you would not evaluate where he measured from because of the ridges. Kowetha Davidson said that HF inhalation is scrubbed efficiently in the upper respiratory tract. She said that the only potential for long-term effects would be when the scrubbing has been exceeded and the contaminant reaches the lungs.

Bob Craig wondered why S-50 was torn down so quickly. Tony Malinauskas replied that the plant was "terribly inefficient" because thermal diffusion was a slow process. Mark Evans believed that no significant uranium dispersion occurred from these facilities to off-site residences.

Danny Sanders asked when the S-50 facility was torn down. Mark Evans said that it operated for 11 months and stopped operating in September 1945; he was unsure when it was torn down. Mr. Sanders asked if any dangers would have existed from residues resulting from the plant being torn down. Dr. Evans said that off-site communities would not have significant exposure because there would not be enough transport.

Bill Taylor asked when gaseous diffusion took place at K-25. Mark Evans said that this occurred from around 1944–1985. Dr. Evans added that according to the release estimates, no significant quantitative emissions occurred from K-25 until about the 1950s. Tony Malinauskas asked if the period when K-25 processed reactor fuel was included. Dr. Evans said that this was factored into the estimates. He added that the summation of gross alpha also included neptunium and other radionuclides, which were all factored in as well. In addition, he noted that the Task 6 report did a "good job" of quantifying the years when recycled products contributed to the process.

Danny Sanders said that he submitted a list of questions to ATSDR. Mark Evans said that he looked at individual questions and summarized them by consolidating certain comments into "significant questions." In addition to air, Mr. Sanders said that his concerns involved the water intake used by the Happy Valley community for drinking water. Dr. Evans did not discuss the water intake because this would be covered in another PHA. Tony Malinauskas asked about the status of that PHA. Jack Hanley said that the water intake would be covered in the White Oak Creek PHA.

James Lewis said that questions could always be answered if they had a Gantt chart to see "where they are." Jack Hanley said that they currently do not have a Gantt chart. However, Mr. Hanley said that they have a time line that Bill Cibulas (ATSDR) committed to and they could respond to each item at the next ORRHES meeting.

Bob Craig asked about the status of iodine 131. Jack Hanley said that this PHA was undergoing data validation. Dr. Craig asked if they would be incorporating monitoring data; Mr. Hanley said that this was correct. Dr. Craig suggested discussing this at the next meeting. Mr. Hanley said that he would talk to Paul Charp (ATSDR).

James Lewis thought they needed to ensure that they advertised for these meetings. He believed that if advertising was done properly, then they would notify people who were interested in certain topics, such as Owen Hoffman. Kowetha Davidson said that Dr. Hoffman was on the e-mail distribution list and received meeting announcements.

James Lewis noted that they have not put any meeting minutes onto the Web site for the past 15 months. Therefore, the general public is unaware of work group and ORRHES discussions. Kowetha Davidson said that these are distributed to the entire e-mail list. She added that they were told that ATSDR would not be updating its old site while preparing a new Web site. Mr. Lewis thought that they had developed a process to distribute this information to the public. Dr. Davidson suggested that Mr. Lewis inform ATSDR of people in the public who are interested, but are not being contacted.

Danny Sanders questioned that Mark Evans was putting all of the concerns together in a "nutshell." He wanted his questions answered as they were written. Dr. Evans said that many questions could be answered using the same information and the same process. He explained that he was responding to questions in the terms of defining the problem, generalizing it, and creating public health determinations. He said that the specific questions were not answered separately in this version, but he would respond to them in the final version of the PHA (after the public comment version was released). Mr. Sanders explained that he is a public member. He was hearing that Mark Evans had "pretty much answered questions in the same way." He did not see a document that had each question answered individually. Dr. Evans explained that the document was not released for the public at this time.

James Lewis stated that they had established a program where all questions would be captured and answered individually. He believed that rolling the issues together resulted in a disservice to the people who raised the questions. Mr. Lewis wanted to look at a complete list of questions, and see how Mark Evans summed the issues. Dr. Evans explained that he used the community concerns database to find concerns from community members. He said that 58 of these were specifically related to the K-25 or S-50 facilities. He said that many of these issues were redundant, and he grouped the concerns into nine public health issues. Tony Malinauskas presumed that all of Danny Sanders's questions were included in these concerns.

Bob Craig said that Mark Evans was trying to incorporate the issues and concerns into the actual analysis of the PHA. Dr. Craig added that once the PHA was issued to the public, then each question would be included. If these were not answered in the PHA, he said that ATSDR would answer the questions specifically. Dr. Evans believed that this was the most valuable part of the PHA for the public. He said that these would not be in the document yet, but they would be listed in a later version of the PHA.

James Lewis thought that the program was supposed to capture all of the issues expressed in meetings, papers, and other sources. He said that this never occurred. He believed that ATSDR had an incomplete list of questions and he wanted the agency to make an effort to obtain as many concerns as possible. Mark Evans thought that the database included all of the concerns ATSDR received in letters, phone calls, work group meetings, and other sources.

Danny Sanders read one of his questions directly to Mark Evans, "Has any resident (man, woman, or child) of Happy Valley ever been exposed to any kind of harmful substances, albeit airborne, waterborne, or transported home by worker personnel in their clothing from any K-25 facility, S-50, or others?" Dr. Evans said there were exposures from S-50 and K-25. He noted that he estimated doses, which showed that there were exposures to off-site residents. Kowetha Davidson added that HF would not be transported home on workers' clothes and that the significant exposure would be through air. Mr. Sanders read another part of the question, "And if so, would you ever expect that there would be any kind of adverse long-term chronic health condition experienced by any of these people as a result of these exposures?" Dr. Evans said that the "doses were all so low" that they would "not be capable of producing adverse health effects."

Danny Sanders asked if the railroad burnyard was taken into account. Mark Evans said that he did not take this into account. Mr. Sanders asked who would handle assessing the burnyard. He said that the government put their "parents at risk because they put them in an encampment like that." Dr. Evans recalled that the burnyard was on the west side of the K-25 facility–not to the south where Happy Valley was located. He said that the predominant wind direction would not take "much of anything to Happy Valley."

Bob Craig explained that they had gone through a screening process to identify the nine COCs and did not hear about a burnyard during this process. However, he said that this could always be added if something of potential health concern was identified.

Danny Sanders said that ATSDR would not have included Happy Valley if he had not brought the information to the agency. He wondered why the government had not told ATSDR about the community. Tony Malinauskas said that it is their job to make certain that the document is complete and that every issue has been covered.

Danny Sanders asked about Mark Evans's statement that UF₆ was one of the "big issues of releases." He questioned if any other chemicals were typically being released to the air. Dr. Evans said that there were a few others, including water from cooling towers and some nickel. However, Dr. Evans explained that because these were not part of S-50, Happy Valley would not have been affected. Dr. Evans added that Happy Valley was not in existence when "much of anything" was released from K-25; only releases from S-50 could have been a factor for Happy Valley. He noted that K-25 did not have significant releases until about 1950.

James Lewis noted that Danny Sanders has been "very tenacious about attending these meetings." He said that they cannot make the assumption that people who attend the meetings can make leaps from the questions they asked to the summarized concerns in the PHA. He said that ATSDR needed to answer these questions or they would never reach the public.

Tony Malinauskas said that the questions that have been asked cannot be answered until the work has been completed. James Lewis said that ATSDR does not even have the "questions that were raised captured in an organized format." Danny Sanders asked if his questions were in the PHA. Mark Evans replied that they were not listed individually; he had read all of the questions and summarized them. Dr. Evans believes, however, that each question should be listed and answered individually in the PHA. Judy Fussell noted that when they are dealing with the public who will be reading this document, ATSDR needed to have the questions and responses listed out separately.

Mark Evans said that the PHA in its current state looked at the "bigger picture" (e.g., doses). He explained that he had to define the problem technically and scientifically in order to answer the questions. Judy Fussell asked if Dr. Evans would then answer the questions for the layperson; he said she was correct.

Judy Fussell noted that people living in the encampments were transient. Therefore, to learn about each person, they would have to follow each person's path. Mark Evans replied that this was the reason he looked at the doses. Kowetha Davidson explained that different people have different sensitivities, and that hypersensitive individuals cannot be accounted for. Ms. Fussell said that they do not have people from whom they could obtain assessments. Tony Malinauskas added that it would be "impossible" to obtain information on every individual who lived in that area during the time period of interest.

According to Mark Evans's presentation, Bob Craig said that people would not have been harmed at the average level of concern.

Judy Fussell has wondered about the long-term health effects on herself because she was in utero while living in Happy Valley. She believed that they may not have all of the data for another 10, 15, or 20 years. Kowetha Davidson said they needed to remember that the sum total of what occurs to one person is the sum total of what occurs to that person over his or her lifetime. She explained that this makes it difficult to take exposures that may have occurred over a 3-year period because everything that happens to an individual contributes to his or her exposures over a lifetime. Ms. Fussell wanted them to keep in mind that if eight out of 15 people developed the same disease, then they would start here because it is what they have in common. Dr. Davidson replied that they would need to track their evaluation back to something the person was exposed to at high enough concentrations, but they have not found exposures that would justify this type of further investigation. Ms. Fussell did not "see how they can rule out anything."

Tony Malinauskas said that the next meeting would be held on March 21, 2005. He adjourned the meeting at 7:10 pm.