Oak Ridge Reservation: Public Health Assessment Work Group
Public Health Assessment Work Group
July 1, 2002 - Meeting Minutes
ORRHES Members attending:
Bob Craig, David Johnson, Susan Kaplan, James Lewis, LC Manley
Public Members attending:
Walter Coin, Bob Peelle, Iulian Apostoaei, Gordon Blaylock, Melissa Fish, Beth Freeman, George Gartsteff, Mike Knapp
ATSDR staff attending:
Jack Hanley, Bill Murray
Approval of previous minutes, if available (10 min) - Bob Craig
Combining iodine-131 (I-131) doses from ORR and NTS
(60 min) - Bob Craig
Radiation screening write up by Paul Charp (60 min) - Bob Craig
PHA Update (5 min) - Jack Hanley
New business (10 min) - Bob Craig
Issue #1: Minutes
Discussed minutes from previous meeting. Group agreed to approve minutes in the next meeting after members have had a chance to review them.
Issue #2: Combining 131I doses from ORR and the Nevada Test Site
Someone had read through Kowetha Davidsons’s presentation and thought it was very well done.
Susan Kaplan reported than Owen Hoffman wanted to make a few comments about Kowetha’s presentation:
- Owen Hoffman encourages the group to develop a rationale. This is
not necessary from a public health communications perspective, but it
is important to the people who synthesize the information.
- Kowetha Davidson had an overhead about CDC/NCI. Global sources add only 10% to excess cases of thyroid. Owen questioned whether there were really data to support this claim.
Someone said that fallout adds very little risk to affected Oak Ridge populations.
If you want to tell people what their local risk is, you should combine the two values. If you want to tell people what happened because of a particular plant, you should.
The group should be looking at the reservation for all the other sources and combining them.
The argument can be made that all these sources had to do with weapons during the Cold War. If you wanted to assess risk from the weapons program, then combine them.
Susan Kaplan thinks it is the group’s responsibility to look at all the different factors.
Bob Craig mentioned the group is charged to look at just the local issues.
Can we do a comprehensive dose reconstruction?
Just because you can “rub two numbers together,” should you? What about the dose and the uncertainty associated with it? When you rub these two numbers together and combine them, and there is so much uncertainty, how important is the uncertainty? When you go from dose to risk, the uncertainty skyrockets.
How does the uncertainty increase when you go from dose to risk?
You add the uncertainty about what the dose actually does.
Dose estimates encompass a range slightly greater than a factor of 10, excess cancer risk ranges from 1 in 100 to one in a 1000.
Jack Hanley: If we put together questions now, Kowetha Davidson can address them later.
Susan Kaplan: Kowetha Davidson’s recommendation hinges on the assumption that we are not going to add risk.
Are we asking what the dose is or what the impact of the Oak Ridge facilities is?
Mike Knapp asked what is meant by a tremendous amount of uncertainty? 60%? 90%?
Let’s move forward.
So thyroid cancer occurs about four years after exposure? Yes, in cases of very high dosages (Chernobyl).
Jack Hanley: Summary of what Kowetha Davidson came up with when she listened to Dr. Miller’s presentation. Susan Kaplan asked Dr. Miller about the significance of the dose. Dr. Miller said that the dose number itself is not important. From NTS, his dose ranged from 0.0 something to 200 something. There was a very large range. What is more important are the factors of exposure. How old you were, where were you at time of exposure? Did you drink backyard milk? There are a range of uncertainties in doses. Once again, what’s more important is: gender, did you drink backyard milk? Unless you are going to assess the probability of causation, exact dose is not so important.
Susan Kaplan: Owen Hoffman mentioned that excess probable risk is a very simple concept, it is not limited to legal contexts.
Jack Hanley: We don’t use probability of causation in public health assessments. In epidemiology, maybe. It’s not in our guidance manual.
We can’t discuss Kowetha Davidson’s recommendations until we discuss her report further.
James Lewis: Owen Hoffman mentioned a local program that was going to combine the doses and look at the entire country on a national basis. Was the National Academy of Science going to do this?
Are we looking at the public at large or individuals?
For people living in Solway or Bradbury, what is more important than dose is whether you were female, drinking backyard milk, or born between 1948 and 1956.
ORHASP looked at combined doses, didn’t they?
Iulian Apostoaei: Without adding the doses, the study will be inconclusive. We need to define background, and then add risks from the facility.
Neither presenter (Hoffman or Miller) specifically recommended combining doses when they presented in June 11.
Kowetha Davidson said that Owen Hoffman noted that a more refined dose reconstruction would not be necessary for a health assessment, but it would be to establish causation.
If you exclude the NTS data, you’re going to understate to the public what their dose is.
What kind of information are people going to want? Just releases from Oak Ridge in a particular time frame or total exposure?
Jack Hanley: If someone lived in the area and were likely exposed, what kind of information would they want? An epidemiologic study? An educational program? A risk screening?
They want medical attention and they want to know all the ways in which they have been affected.
Iulian Apostoaei: We can divide people into two groups: People who don’t have any disease want to know what the risk is of living in a particular area. People who have cancer want to know who or what is responsible.
James Lewis: We may be focusing on small groups when we should be looking at larger groups.
Jack Hanley: Our data are on a county-wide basis, not on an individual level.
Should we contact Steve Simon of the National Cancer Institute (NCI) and see what he says?
Uncertainties in dose reconstruction are on a factor of 2 to 5.
James Lewis: What did Dr. Miller say about the program that was going to look at it?
Jack Hanley: CDC has some money from Congress to study weapon releases. Another study was done by the NCI. Within 12-18 months, the NCI was going to produce educational material based on this study.
Susan Kaplan: If we ignore NTS data, we will put this committee’s credibility’s on the line.
James Lewis: You have to define the public. Some members of the public would agree with ignoring NTS data. Some vocal people will complain.
Jack Hanley: Kowetha Davidson is recommending that we not combine NTS data with Oak Ridge data because of NTS data uncertainty. Give people a dose calculator so they can add NTS and Oak Ridge together if they want.
Iulian Apostoaei: Why is Kowetha Davidson concerned? Uncertainty in the NTS data is only very large with respect to underground testing.
Jack Hanley: Should we add just the NTS data from the above ground tests?
Iulian Apostoaei: Add everything. Take two quantities: a large one with 10% error (say, 50 +- 5) and you add it to a small one with a 100 fold error range (say, 0.01 to 1). When you add the two quantities, the final uncertainty isn’t a problem. It is fine to add the two values together, even when dealing with uncertain data from underground tests.
What about Russian tests?
Iulian Apostoaei: NCI is working on that.
Dr. Miller is a branch chief at CDC.
Would he have become branch chief if he had responded differently?
Jack Hanley: What does it mean to add the data with all the uncertainty? Dr. Miller mentioned that he would use a qualitative approach to evaluate risk, not a dose reconstruction.
Issue #3 Radiation screening write-up by Paul Charp
Paul Charp’s paper is based on approach #1, which is dose. But there is also another approach based on risk. Owen Hoffman supports approach #2, based on risk.
ATSDR has a standard approach. We’re looking at a public health assessment. We’re not looking at individual causation.
EPA and other agencies use approach #2 (risk-based), right?
There are many agencies with many different ways of looking at the issue.
Jack Hanley: EPA has reference doses for chemicals which they know are safe. At that level, it won’t cause problems. ATSDR is interested in the dose that causes an effect, with which they can make health decisions.
It wouldn’t make sense to use a risk level that is lower than background because that would include everything.
Comments on the writeup were collected.
Issue #4 PHA update
Jack Hanley is working with DOE management to obtain iodine data. Paul Charp is working with new data that were received from DOE. One critical year, 1954 weekly monitoring data, is missing, but DOE is still looking for it. There are also some outstanding questions about how to use the data. These data were from monitors that picked up all particulates, regardless of source, RALA or wherever. These data could potentially make some of our discussion in Issue #1 obsolete because everything would already be included in the data.
With regard to uranium, we are working with management to get modeling assistance. Mark Evans might help us. Karl Markiewicz is now working on Oak Ridge again. He will be working with a database of chemicals.
CHEMRISK has a database of documents that were looked at. It includes monitoring reports dating from 1953, from ADDE. The monitoring reports were for stations both inside and outside the fence.
James Lewis: Regarding Owen Hoffman’s report on what remains to be done. It looks like an entirely new project to validate what we’re doing. Apparently we need to archive data about what was actually measured in the 1950s and 1960s. Milk data collected by PHS and EPA cannot be located. Other data sets are disappearing. Will missing data have any impact?
Answer: Yes, they could impact our results.
James Lewis: At what point do you have enough data?
Jack Hanley: At some point you make a decision. The data we are getting are actual measurements, not modeling results.
Everyone is encouraged to turn in their comments to Bill Murray.
The meeting is adjourned. Next meeting in two weeks.